removed for privacy reasons

I have the solution to this problem. I'll repost what I posted in another thread in response to Purple Pond.

I realize it is a strange idea that I am asking you to consider. Bear with me a bit and keep an open mind and consider the following. It is long, I know, but I don't know how else to get this across. If you get what I am trying to communicate, I think you'll see that it neatly solves all of the many puzzles of personal identity is a possible solution almost always left unconsidered.

Have you ever wondered why you find yourself being the particular person you happen to find yourself being? Don't look at it from an objective standpoint. Look at it from a subjective standpoint. Ask yourself, "Isn't it a little odd that I happen to find myself being Purple Pond and not someone or something else?"

First, consider that having a subjective perspective and being someone isn't an objective state of affairs. If you were to restrict yourself to third-person language and describe the world, there is one thing you couldn't declare: which of the entities in the world you are. You could say things like "Purple Pond is sitting in a chair looking at a screen" or "Oysteroid is wearing a white sweater" or "Purple pond says that he is Purple Pond". You couldn't say "I am Purple Pond." Finding yourself as a particular person, occupying a particular perspective, is something other than an objective fact, something that reveals itself to be more than a little mysterious if you think about it for a while.

What are the odds that out of all of the 3 pound hunks of matter out there in the vast universe or maybe even infinite multiverse, most of them lacking biology, you just happen to find yourself being a human in this special place and time? Did you win the cosmic lottery a hundred times over or something? Shouldn't you find it a bit surprising that you find yourself occupying such a privileged vantage point on the world? After all, it seems, you might have been a mouse instead, or a bacterium, or a cloud of dust or a rock in outer space.

Suppose we have a big bucket filled with a trillion marbles, one of which is gold, the rest of which are blue. We blindfold you and have you dig around and withdraw a marble. Then we ask you whether or not you should expect to take off the blindfold and find yourself holding a gold marble. Of course, the answer is no. With a random sample, you should expect to have a typical sample. If you do end up finding yourself with the one in a trillion golden marble, shouldn't you find this surprising?

Now consider how rare life is, how rare brains are, as far as hunks of matter go. Even as far as brains go, human brains are extremely rare. Even if the only thing it is possible for a self to find itself as is a human brain, isn't it weird that you are this particular one, and not another? What is it that determines which vantage point on the world you have?

From an objective perspective, of course Purple Pond is Purple Pond! How can it be otherwise! A is A! But that ignores the issue. The issue is your subjective perspective and your being someone.

People say, "I am my brain." What does that really mean? They are connecting something, their 'I', to something else, a particular brain, and saying that A is B. Isn't this a bit odd? What is this 'I'? To be a truly separate individual, it is as if you have your own 'I' and I have another one, as if each brain has a unique 'I' associated with it. But this idea, resembling the old individual soul idea, just adds mystery to mystery. Suppose you are a soul, even if you don't believe in such things. Why are you this soul and not a different one? Same problem. And on you would go with an infinite number of homunculi within homuncili.

Consider further what a strange idea it is that you can be something, some arbitrarily extended, but limited, collection of physical particles. People sometimes ask what it must be like, if it is like anything at all, to be a rock. Notice what they are doing! Is there some magical boundary around a rock other than the one we impose when we see a rock and identify it as such, mentally separating it from its surroundings? If a rock, which is a collection of many smaller things, why stop the collection at that point? Why not a pile of rocks? Why not the mountain? Why not the planet? Why not the whole universe?

But isn't it strange that you could be a collection of things in the first place? Let's simplify this so that the issue becomes more clear. Suppose you were to find yourself being a thing that is composed of exactly two things, perhaps two quarks. How can you be a pair of things? Isn't that a weird idea? How is it that you have this span, that what you are can extend beyond just one thing to include more?

Gilbert Ryle used to talk to his students about the question of whether there are three things in the field, two cows and a pair of cows. This makes me chuckle.

When people claim to be a brain or a whole body or whatever, they are saying that they are a huge collection of things, that their identity has this incredible span. Why not half the brain? Why not a single neuron? Why not two brains? Why not everything?

And then you get into all the usual problems of personal identity. Are you the same person over time? But the atoms in your body are changing. The form is changing. Whether you are the very atoms or the pattern in which they are arranged, this creates problems.

If what you actually are is this particular, arbitrary set of particles that currently composes your brain, then after a while, you become dispersed and might end up being split up over multiple bodies as other creatures eat the matter that once composed your body. And if you are these specific particles, realize that they were once separated and belonged to many different organisms. What are the odds that the collection that is you just happened to come together in one brain, all at the same time?

No, you couldn't simply be identical with this collection of atoms! What about the form, the pattern? If you are a particular pattern, consider that the form is constantly changing! You would only exist momentarily! There would be a succession of many, many separate selves, each living a moment in the course of a life.

That doesn't make sense either, does it? So what are you? Consider that you already accept, if you believe that you are a brain or a body, that what you are spans multiple things. It involves multiple particles, multiple cells, multiple organs, a span of time with many states, and so on. It is just that you think that what you are ends with your skull and your birth and death. But why would it end there? Is that some kind of magical boundary that encapsulates an ego? Does a skull boundary define an 'I'?

I think we tend to find it easy to accept that we are a brain, and to not notice that we are thinking that we are a multitude, because of the fact that, because of how our minds carve up the world into things, we think of the brain as one thing, like Ryle's pair of cows.

And then you can consider all the questions that arise with teleporters and the like. If we read all the information describing your body, destroying your body in the process, and then assemble a copy at a distant location, when the person steps out of the teleporter, is that person you? Do you, the same you that you are now, find yourself then on the other side? What if we make two copies? Which one will you be, if any? Or did you die?

How do you know that your form propagating from moment to moment isn't just like that teleporter? Is the experiencer of your perspective this moment the same one as an hour ago? I would say yes, obviously. Otherwise you couldn't experience the flow of time. Your identity must span time in order for you to experience change. And your identity must span some space and material in order for you to have a unified experience of all that your brain is doing, even to experience an apple as an apple, with its combination of color, shape, meaning, and so on, the processing of which involves many brain regions.

So you already have span, both temporal and spatial. You are already more than one thing and more than one state of those things. So why do you think that what you are is limited to this body and its lifespan?

Consider how the idea that you are simply that which is everything, that it is all one and you are it, would solve all of these problems in one fell swoop.

Why do you find yourself being Purple Pond? Well, being everyone and everything, you'd naturally expect to find yourself being Purple Pond. Consider the marble picking again. If you were allowed to hold all the marbles, should you be surprised to find yourself holding the golden one?

Think about it probabilistically. If you are in one of two scenarios, with you not knowing which, and you had to guess which one you are in, which should you bet on, the one in which your case is far from typical or the one in which your case is typical or even inevitable? For example, suppose we flip a coin and determine which of two prizes you get: A, all the marbles, including the golden one, or B, just one marble selected at random. Now suppose that before we tell you the result of the coin flip, we tell you that you definitely have the golden marble. Which should you expect to be true, that the coin chose A or B? You should guess A. In that case, having the golden marble is something you'd expect. In the other case, it would be a big surprise.

The fact that you find yourself being Purple Pond, being a brain at all, being alive at all, being in an inhabitable universe at all, and so on, is absolutely inevitable if you are everything, and astronomically unlikely if you are just one arbitrary three pound thing on a particular arbitrary planet, in a particular arbitrary galaxy, and so on.

Think about a lottery win. If you describe the situation objectively, it is not very surprising when someone wins. But if you find that you are the winner, that is a different thing, isn't it? That is surprising! But notice that it suddenly ceases to be surprising, even subjectively, if you happen to be everyone.

This idea even clears up all the confusion about the anthropic principle and the fine-tuning of the cosmos and whatnot. Why does the universe seem so fine-tuned? Suppose there is an infinite multiverse containing all possible universes. In one of them at least, these conditions will prevail. And if you are everywhere, naturally, you should expect to find yourself alive in a universe fine-tuned for life! But if you aren't everything, if you are just one arbitrary three pound hunk of matter, inexplicably having both span across a multiplicity of things and a limit to that span, then your situation is indeed unusual and suprising to find yourself in.

But there is a natural objection to all of this. Why don't you feel yourself being me and everyone else? Why don't you know that you are everyone? Why can't you access my memories?

There are some famous cases in which people with severe epilepsy have undergone a procedure in which the corpus callosum in their brain has been severed, effectively isolating the two hemispheres. If you aren't familiar with this, I'd suggest researching and reading about split-brain surgery. What results from this is a situation in which it seems that there are now two selves, one for each hemisphere. Using clever methods, you can ask one hemisphere a question and give it information while avoiding giving any information to the other. You quickly find that if you ask one hemisphere questions about what you have only shown the other hemisphere, the answers contain no information about it. You can show that there is no integration of information between the hemispheres. Further, the two hemispheres seem to have distinct desires, distinct plans for the future, and so on. And sometimes, one hand will try to button up a jacket while the other tries to keep it unbuttoned, and so on. Suddenly, it seems that there are two people in one skull, each controlling half the body.

What has happened here? Can your self, the very you that you are, be divided into two? If you undergo such a procedure, which of the hemispheres will you find yourself being afterwards?

Consider another hypothetical scenario. We take a guy named Bob, who is an amnesiac who cannot remember new information for longer than a few minutes, and we place him in a room with a chalkboard mounted on the wall. We show him things, give him experiences, and he records what he observes on the board. When we ask him what we have told him or what he has experienced, he consults the board. It basically serves as his memory. Now, suppose that we take him to a second room, room B, also with a board. But this board is blank. In this room, he does not have any access to what he wrote on the board in room A. We can replicate all the experiments from the split-brain studies using Bob in these two rooms, and we can show that there is no information integration between the rooms. In room B, Bob cannot give information about what he observed in room A, and vice versa. And he can't connect things observed in the two rooms.

Obviously, we can't conclude from this that there are two separate people here, one in room A and one in room B. Bob is one person regardless of the inability to integrate information between the rooms. The only issue here is that there is no way for information to pass from room A to room B and vice versa. While in room B, Bob knows nothing of his life in room A. He doesn't remember being in room A. He might have written a concerto in room A, but he would know nothing of it while in room B. If we give him a portable notebook, he might then integrate information between the two rooms, but without such a device, there is no reason to expect him to have access to information in the other room. The same goes for the two hemispheres in the split-brain. The corpus callosum is like a notebook allowing information to pass between hemispheres.

What's the point of this Bob business? I'd suggest that the very same situation holds for us as seemingly separate individuals. Our two brains are like the two rooms. There is one experiencer with both perspectives simultaneously, but over there, in your brain, there are obviously no memories from my brain. How would they get there? They'd have to get there by some local physical mechanism. In this brain over here, I lack access to what is stored in that brain over there. In the Oysteroid brain, I find no Purple Pond memories, naturally, and vice versa. And that's all there is to it. That's why we think we are distinct selves. In actuality, I believe, that which we are, that deepest inner witness that looks out from behind these eyes, is everywhere and is everything. And it isn't a separate self inhabiting the multiverse, as if there is one big soul assigned to one big multiverse. No! It is all just one whole. Your very self is the very substance of it all. The scenario with Bob isn't a perfect analogy here, as Bob is separate from the rooms.

There is one substance and it experiences all of its modifications and relations and is everywhere present to itself. And if you want to know what it is like to be it, just ask yourself. You're it. You're everything.

It isn't like reincarnation, where you can look forward to another life. No, you are living them all simultaneously and always. You are already over here, experiencing my life. You are already beyond the life of Purple Pond. You just can't access this information from there. While in that room, you don't know that you are also in this room and all the other rooms.

Take this seriously. Think about it. And realize that there is never again cause for envy. When you see someone else enjoying some life that you don't have, know that you have it, that you are that person. Also know that when you hurt another being, you are hurting yourself. It is none other than you that has the experience on the other side of whatever you do to another.

If you have made it to the end, thanks for giving all this your consideration!

I find that hard to believe.

I realize it is a strange idea that I am asking you to consider. Bear with me a bit and keep an open mind and consider the following. It is long, I know, but I don't know how else to get this across. If you get what I am trying to communicate, I think you'll see that it neatly solves all of the many puzzles of personal identity is a possible solution almost always left unconsidered.

Have you ever wondered why you find yourself being the particular person you happen to find yourself being? Don't look at it from an objective standpoint. Look at it from a subjective standpoint. Ask yourself, "Isn't it a little odd that I happen to find myself being Purple Pond and not someone or something else?"

First, consider that having a subjective perspective and being someone isn't an objective state of affairs. If you were to restrict yourself to third-person language and describe the world, there is one thing you couldn't declare: which of the entities in the world you are. You could say things like "Purple Pond is sitting in a chair looking at a screen" or "Oysteroid is wearing a white sweater" or "Purple pond says that he is Purple Pond". You couldn't say "I am Purple Pond." Finding yourself as a particular person, occupying a particular perspective, is something other than an objective fact, something that reveals itself to be more than a little mysterious if you think about it for a while.

What are the odds that out of all of the 3 pound hunks of matter out there in the vast universe or maybe even infinite multiverse, most of them lacking biology, you just happen to find yourself being a human in this special place and time? Did you win the cosmic lottery a hundred times over or something? Shouldn't you find it a bit surprising that you find yourself occupying such a privileged vantage point on the world? After all, it seems, you might have been a mouse instead, or a bacterium, or a cloud of dust or a rock in outer space.

Suppose we have a big bucket filled with a trillion marbles, one of which is gold, the rest of which are blue. We blindfold you and have you dig around and withdraw a marble. Then we ask you whether or not you should expect to take off the blindfold and find yourself holding a gold marble. Of course, the answer is no. With a random sample, you should expect to have a typical sample. If you do end up finding yourself with the one in a trillion golden marble, shouldn't you find this surprising?

Now consider how rare life is, how rare brains are, as far as hunks of matter go. Even as far as brains go, human brains are extremely rare. Even if the only thing it is possible for a self to find itself as is a human brain, isn't it weird that you are this particular one, and not another? What is it that determines which vantage point on the world you have?

From an objective perspective, of course Purple Pond is Purple Pond! How can it be otherwise! A is A! But that ignores the issue. The issue is your subjective perspective and your being someone.

People say, "I am my brain." What does that really mean? They are connecting something, their 'I', to something else, a particular brain, and saying that A is B. Isn't this a bit odd? What is this 'I'? To be a truly separate individual, it is as if you have your own 'I' and I have another one, as if each brain has a unique 'I' associated with it. But this idea, resembling the old individual soul idea, just adds mystery to mystery. Suppose you are a soul, even if you don't believe in such things. Why are you this soul and not a different one? Same problem. And on you would go with an infinite number of homunculi within homuncili.

Consider further what a strange idea it is that you can be something, some arbitrarily extended, but limited, collection of physical particles. People sometimes ask what it must be like, if it is like anything at all, to be a rock. Notice what they are doing! Is there some magical boundary around a rock other than the one we impose when we see a rock and identify it as such, mentally separating it from its surroundings? If a rock, which is a collection of many smaller things, why stop the collection at that point? Why not a pile of rocks? Why not the mountain? Why not the planet? Why not the whole universe?

But isn't it strange that you could be a collection of things in the first place? Let's simplify this so that the issue becomes more clear. Suppose you were to find yourself being a thing that is composed of exactly two things, perhaps two quarks. How can you be a pair of things? Isn't that a weird idea? How is it that you have this span, that what you are can extend beyond just one thing to include more?

Gilbert Ryle used to talk to his students about the question of whether there are three things in the field, two cows and a pair of cows. This makes me chuckle.

When people claim to be a brain or a whole body or whatever, they are saying that they are a huge collection of things, that their identity has this incredible span. Why not half the brain? Why not a single neuron? Why not two brains? Why not everything?

And then you get into all the usual problems of personal identity. Are you the same person over time? But the atoms in your body are changing. The form is changing. Whether you are the very atoms or the pattern in which they are arranged, this creates problems.

If what you actually are is this particular, arbitrary set of particles that currently composes your brain, then after a while, you become dispersed and might end up being split up over multiple bodies as other creatures eat the matter that once composed your body. And if you are these specific particles, realize that they were once separated and belonged to many different organisms. What are the odds that the collection that is you just happened to come together in one brain, all at the same time?

No, you couldn't simply be identical with this collection of atoms! What about the form, the pattern? If you are a particular pattern, consider that the form is constantly changing! You would only exist momentarily! There would be a succession of many, many separate selves, each living a moment in the course of a life.

That doesn't make sense either, does it? So what are you? Consider that you already accept, if you believe that you are a brain or a body, that what you are spans multiple things. It involves multiple particles, multiple cells, multiple organs, a span of time with many states, and so on. It is just that you think that what you are ends with your skull and your birth and death. But why would it end there? Is that some kind of magical boundary that encapsulates an ego? Does a skull boundary define an 'I'?

I think we tend to find it easy to accept that we are a brain, and to not notice that we are thinking that we are a multitude, because of the fact that, because of how our minds carve up the world into things, we think of the brain as one thing, like Ryle's pair of cows.

And then you can consider all the questions that arise with teleporters and the like. If we read all the information describing your body, destroying your body in the process, and then assemble a copy at a distant location, when the person steps out of the teleporter, is that person you? Do you, the same you that you are now, find yourself then on the other side? What if we make two copies? Which one will you be, if any? Or did you die?

How do you know that your form propagating from moment to moment isn't just like that teleporter? Is the experiencer of your perspective this moment the same one as an hour ago? I would say yes, obviously. Otherwise you couldn't experience the flow of time. Your identity must span time in order for you to experience change. And your identity must span some space and material in order for you to have a unified experience of all that your brain is doing, even to experience an apple as an apple, with its combination of color, shape, meaning, and so on, the processing of which involves many brain regions.

So you already have span, both temporal and spatial. You are already more than one thing and more than one state of those things. So why do you think that what you are is limited to this body and its lifespan?

Consider how the idea that you are simply that which is everything, that it is all one and you are it, would solve all of these problems in one fell swoop.

Why do you find yourself being Purple Pond? Well, being everyone and everything, you'd naturally expect to find yourself being Purple Pond. Consider the marble picking again. If you were allowed to hold all the marbles, should you be surprised to find yourself holding the golden one?

Think about it probabilistically. If you are in one of two scenarios, with you not knowing which, and you had to guess which one you are in, which should you bet on, the one in which your case is far from typical or the one in which your case is typical or even inevitable? For example, suppose we flip a coin and determine which of two prizes you get: A, all the marbles, including the golden one, or B, just one marble selected at random. Now suppose that before we tell you the result of the coin flip, we tell you that you definitely have the golden marble. Which should you expect to be true, that the coin chose A or B? You should guess A. In that case, having the golden marble is something you'd expect. In the other case, it would be a big surprise.

The fact that you find yourself being Purple Pond, being a brain at all, being alive at all, being in an inhabitable universe at all, and so on, is absolutely inevitable if you are everything, and astronomically unlikely if you are just one arbitrary three pound thing on a particular arbitrary planet, in a particular arbitrary galaxy, and so on.

Think about a lottery win. If you describe the situation objectively, it is not very surprising when someone wins. But if you find that you are the winner, that is a different thing, isn't it? That is surprising! But notice that it suddenly ceases to be surprising, even subjectively, if you happen to be everyone.

This idea even clears up all the confusion about the anthropic principle and the fine-tuning of the cosmos and whatnot. Why does the universe seem so fine-tuned? Suppose there is an infinite multiverse containing all possible universes. In one of them at least, these conditions will prevail. And if you are everywhere, naturally, you should expect to find yourself alive in a universe fine-tuned for life! But if you aren't everything, if you are just one arbitrary three pound hunk of matter, inexplicably having both span across a multiplicity of things and a limit to that span, then your situation is indeed unusual and suprising to find yourself in.

But there is a natural objection to all of this. Why don't you feel yourself being me and everyone else? Why don't you know that you are everyone? Why can't you access my memories?

There are some famous cases in which people with severe epilepsy have undergone a procedure in which the corpus callosum in their brain has been severed, effectively isolating the two hemispheres. If you aren't familiar with this, I'd suggest researching and reading about split-brain surgery. What results from this is a situation in which it seems that there are now two selves, one for each hemisphere. Using clever methods, you can ask one hemisphere a question and give it information while avoiding giving any information to the other. You quickly find that if you ask one hemisphere questions about what you have only shown the other hemisphere, the answers contain no information about it. You can show that there is no integration of information between the hemispheres. Further, the two hemispheres seem to have distinct desires, distinct plans for the future, and so on. And sometimes, one hand will try to button up a jacket while the other tries to keep it unbuttoned, and so on. Suddenly, it seems that there are two people in one skull, each controlling half the body.

What has happened here? Can your self, the very you that you are, be divided into two? If you undergo such a procedure, which of the hemispheres will you find yourself being afterwards?

Consider another hypothetical scenario. We take a guy named Bob, who is an amnesiac who cannot remember new information for longer than a few minutes, and we place him in a room with a chalkboard mounted on the wall. We show him things, give him experiences, and he records what he observes on the board. When we ask him what we have told him or what he has experienced, he consults the board. It basically serves as his memory. Now, suppose that we take him to a second room, room B, also with a board. But this board is blank. In this room, he does not have any access to what he wrote on the board in room A. We can replicate all the experiments from the split-brain studies using Bob in these two rooms, and we can show that there is no information integration between the rooms. In room B, Bob cannot give information about what he observed in room A, and vice versa. And he can't connect things observed in the two rooms.

Obviously, we can't conclude from this that there are two separate people here, one in room A and one in room B. Bob is one person regardless of the inability to integrate information between the rooms. The only issue here is that there is no way for information to pass from room A to room B and vice versa. While in room B, Bob knows nothing of his life in room A. He doesn't remember being in room A. He might have written a concerto in room A, but he would know nothing of it while in room B. If we give him a portable notebook, he might then integrate information between the two rooms, but without such a device, there is no reason to expect him to have access to information in the other room. The same goes for the two hemispheres in the split-brain. The corpus callosum is like a notebook allowing information to pass between hemispheres.

What's the point of this Bob business? I'd suggest that the very same situation holds for us as seemingly separate individuals. Our two brains are like the two rooms. There is one experiencer with both perspectives simultaneously, but over there, in your brain, there are obviously no memories from my brain. How would they get there? They'd have to get there by some local physical mechanism. In this brain over here, I lack access to what is stored in that brain over there. In the Oysteroid brain, I find no Purple Pond memories, naturally, and vice versa. And that's all there is to it. That's why we think we are distinct selves. In actuality, I believe, that which we are, that deepest inner witness that looks out from behind these eyes, is everywhere and is everything. And it isn't a separate self inhabiting the multiverse, as if there is one big soul assigned to one big multiverse. No! It is all just one whole. Your very self is the very substance of it all. The scenario with Bob isn't a perfect analogy here, as Bob is separate from the rooms.

There is one substance and it experiences all of its modifications and relations and is everywhere present to itself. And if you want to know what it is like to be it, just ask yourself. You're it. You're everything.

It isn't like reincarnation, where you can look forward to another life. No, you are living them all simultaneously and always. You are already over here, experiencing my life. You are already beyond the life of Purple Pond. You just can't access this information from there. While in that room, you don't know that you are also in this room and all the other rooms.

Take this seriously. Think about it. And realize that there is never again cause for envy. When you see someone else enjoying some life that you don't have, know that you have it, that you are that person. Also know that when you hurt another being, you are hurting yourself. It is none other than you that has the experience on the other side of whatever you do to another.

If you have made it to the end, thanks for giving all this your consideration!

...am I the same person?

What do you mean by "person"? Are you asking if the two bodies are the same body, if they are in fact not distinct after all, being one body? A is A? Or are you asking something more along the lines of whether there are two different subjects, two different experiencers?

If you are talking about the bodies, if they are defined as distinct and if there is some way to finally distinguish them, some way to show the two universes to be distinct, then I guess they are distinct, in which case they can't be the same body. If A is not B, then A cannot be B. If A is A, A cannot be other than A.

But if they are truly indistinguishable, by the identity of indiscernibles, it would seem that it makes no sense to say that there are two separate things. If two universes are perfectly identical in every possible way and there is no way to tell the difference, how can they be said to be different? Are they separated somehow, say spatially? I'm not sure what a spatial separation between universes would mean, but in that case, they wouldn't be identical. There would be at least one difference, namely, that of location.

If you are getting more at the subjective experience and perspective, then I'd say definitely yes. That which fundamentally has the experiences finds itself being both people. You, the real you, inhabit both universes. But there is nothing particularly special here about the fact that the two bodies are identical and yet distinct. You, the real you, also find yourself being everyone and everything else. You are me as well. You find yourself occupying every perspective.

There is only one real self. There are no truly separate individuals. The illusion of separate selves is the result of incomplete information integration between different parts of the world.

I haven't read every comment in the thread, so I hope I'm not repeating anything. After reading quite a few, a number of considerations come to mind.

First, regarding the idea that in order for two things to interact, that they must occupy the same space, consider a "space" in a computer simulation or game and the computer, the code, and the world outside of the sim and how they can interact. You could have a virtual space in the simulation in which there are "local", "physical" interactions according to laws given by the code. A body in that world could be an avatar for some entity that isn't an occupant of that virtual space. And some means of interaction could be provided for in the code that would not be detectable in the game world. We do such things all the time in MMORPGs. It is clearly not the case that the things in the game world cannot interact with things outside of it. A player interacts with that world through input devices, but that input is not detectable from within the game world.

Sure, you might then argue that there really is no game world, that everything involved actually resides in the higher, truly physical world, that all "interaction" inside the virtual world is illusory. But such a situation could also be the case in our physical world. Even body-to-body interactions as we imagine them might not be truly mediated via physical mechanisms through space and time. Their true background and what gives rise to correlations between them might go deeper and might be inaccessible to us, belonging to a deeper world that we can't know directly through this one. I'd say that the whole concept of the physical is rather muddy anyway. We don't really understand "physicality" or even substantiality as well as we tend to think we do. Nor do we understand consciousness. Reducing everything to one or the other and then declaring the problems and mysteries eliminated is foolishness.

How do thing-to-thing interactions in the physical world actually occur? Do they occur? Doesn't such an idea assume that there are multiple truly distinct things interacting? In order for there to be interaction in the strict sense of the word, doesn't this require that multiple things are involved? And doesn't this actually run afoul of what Spinoza argued about the problem with multiple substances? If you conceive of particles as truly separate, independent things, one from another, things each standing on their own, so to speak, having self-existence, you are talking about multiple substances, substance here being used in the traditional metaphysics sense. And multiple substances interacting is usually considered problematic. For one thing, if they are truly independent, why are they the same in so many ways? Why are all electrons basically identical? And why do they occupy the same space? How would truly independent substances have anything in common? And if things are not actually separate, then how can they be said to interact?

It could be that the concept of interaction itself is problematic, as it relies on there being a true multiplicity. Instead, all of reality might involve wholeness.


What are we really talking about anyway with causality? Do we even know?


Also, consider that space at least, if not time also, is possibly emergent and not necessarily fundamental. It seems to me a rather old-fashioned way of seeing things to think of atoms and the void as ultimate fundamentals, and yet most people seem to think in this fashion when thinking about the physical, even though modern physics has given us plenty of reason to raise questions here. For one thing, such a view leaves space, time, and atoms unexplained, as well as the laws that govern them. What is space? Is it just an emptiness or absence of things, or is it substantial? Is it a something itself? Is there a "fabric" of space? What is time? What are atoms? How do they interact? How is it that they have substantiality? How is it that there are multiple things? Why are there many identical things? Why do they have the particular properties they do?

In Einstein's theories, space gains its own degrees of freedom and seems to cease to be the empty void of Democritus that people still seem to imagine. What is it then? If spatial geometry can change, what is it that is changing? And what is it exactly that determines that a certain thing is in a certain place in space? How does that thing "know" where it is? How does the universe "know" where it is and whether it will interact with another thing?

There are all sorts of interesting things to think about. If the only thing in the universe is a single astronaut floating in space, where is he? How fast is he moving? Suppose there is another astronaut in view. Who is moving? There is relative motion. Without the other, velocity is undefined. With two astronauts, information about each is available to the other by way of things like light (maybe the astronauts have flashlights), gravity, and so on. But drop down to the level of a single sub-atomic particle. Until an interaction occurs, aren't its position and momentum undefined? At that level, unlike at the level of a large astronaut, where many, many interactions are involved in seeing another astronaut, interactions are comparatively rare. As a single tiny particle, you can't "see" the world around you. You aren't big enough be struck by enough photons or whatever in order to gain information about your surroundings. Prior to an interaction, it would seem, you are effectively isolated, and so your position, momentum, and so on, are undefined. Only upon interaction does any of this become defined. And since things are quantized and discrete, interactions are seemingly on and off. If light were continuous, particles could maybe be thought to receive tiny quantities of light from all around, from many, many objects, and thus not be so blind. The discreteness and quantization gives a different picture. But if you need interaction to gain definite position and momentum, how is it determined whether the interaction happens or not? If it isn't "known" where the particles are, how is it "known" if they collide? Seemingly, interaction is needed to generate information about relative states, but information about relative states is needed to decide if interaction occurs. What is it that keeps track of their respective positions and momenta, if anything? A real position in a real space? What does that mean? Is that compatible with the uncertainties of QM? In a computer simulation of particles, we keep track in the computer's memory. The computer "knows" and compares the positions. What about in the physical world?

How is any of this relevant to the discussion? I think there are questions that few ask about how any sort of interaction occurs. An interaction between two particles in space might require a third unknown factor, one transcending space. And if such other factors could be involved, why couldn't they possibly mediate mind-matter interactions? We just don't know enough to rule such things out. We don't know what mind really is. We don't know what matter/energy really is. We don't know what space is. We don't know what interaction really is. We don't understand causation. So deciding what is possible by means of arguments such as the one presented in the OP is more than a little misguided, it seems to me.


Recently, there has been some stir in the physics world over ER=EPR, and some are beginning to think, in possible glimmers of a theory of quantum gravity, that space itself is emergent and is "stitched together" by entanglement, and represents a sort of network of particles (not particles in the intuitive "tiny rock" sense). But if space is emergent in this sense, where do the particles that, by their entanglement structure, give rise to it, themselves reside? Another space? Why is that needed?

Where, for that matter, is the universe located? Does it have location?

Consider a computer program in which you define a bunch of nodes with "links". Create rules such that information can be moved from node to node, but only across links. Information can be passed at a rate of only one link per time step. Suppose you have nodes linked in a series such as A-B-C-D-E.... Information can go from A to B to C, but never A directly to C, since no such link exists. What happens here is that a sort of space emerges, a one-dimensional space. But in reality, A, B, C, D, E, and so on, are not actually spatially located. They are distinguished logically or informationally only. Spatial "proximity" here takes on a new meaning, having to do with the arbitrary structure of the network. The nodes themselves actually have no location in any true space.

Our space could be analogous to this in that there might not be any true, ultimate space in which particles reside. Reality might be more fundamentally logical/informational.

In our computer program, we could create more emergent spatial dimensions by linking nodes in more ways. We could have A1 linked to both B1 and to A2, for example, giving something like rows and columns. You could then have a 2D "space" "inside" the network, in which such games as Conway's Game of Life could happen. If you are an inhabitant of such a world, it might appear that all causal interaction is truly happening at the level of the things inside that space, between things locally acting on one another, one cell literally touching and thereby influencing its neighbor. In reality, what is responsible for that apparent interaction is something altogether inaccessible to the contents of the game world. It has more to do with the computer running the program and storing information in variables, executing conditionals, comparing variables, and so on. Similarly, in our world, many things might be completely hidden from us. Many of the conditions for the possibility of what we see happening might be based in something happening in a realm transcending the one we have access to.

Remember that correlation doesn't demonstrate causation. What might at first appear to be A causing B might in fact be C causing both A and B. Every time the mercury in the thermometer rises beyond a certain point, I also start sweating, but it would be a mistake to conclude that the rising mercury is causing me to sweat. And realize that when we think we observe physical causation, all we are really seeing is correlation. Every time X occurs, Y occurs. We are seeing patterns in our experience. We don't have any deep justification for our belief that one billiard ball striking another is fundamentally and finally what causes it to move.


Consider being stuck in a dream you can't wake from and trying, from that vantage point, to address certain factors that affect the dream world, such as your physical body. You cannot find that which governs the contents of the dream inside the dream. You can't find, strictly within the dream world, the brain that dreams it. You could not, for example, excise your brain tumor through the dream world. Similarly, in an MMORPG, you cannot find the player of the game inside the game world. You cannot find the computer on which the game is running inside the game world. You cannot find the code inside the game world.

Suppose we create a simulation in which we have a physics that works at the particle level and we evolve a complex world there built of these virtual particles. Now imagine that a scientist composed of such particles studies that world experimentally and adheres to the idea that reality consists only in what can be experimentally verified. Could that scientist, by means of his experiments, ever gain access to the computer on which his world is running? Could he discover the programmers? He might manage to discover laws, and thus, to some small extent, something of the code behind the simulation, but that's about all. So if he were to define reality as being limited to that which is composed of the particles in his world and their interactions, and that which is verifiable by experiments performed on these particles, he would be making a mistake, wouldn't he? He'd be rather short-sighted, but understandably so.


Also, what relevance might Kant have in this discussion? In his view, aren't space and time categories of the understanding? How does this affect the question of interaction between mind and body?


I think it even possible that the physical world is something that happens emergently inside mind, or is in some sense the content of mind, or represents the structure, seen at a certain level, of a kind of mental activity. After all, physics seems to reduce to math and information and maybe ultimately logic, which are themselves decidedly not very "stuff-like", seemingly rather more like cognition. We still, because of physics history, call the small constituents of reality "particles", but when you really examine the concept, the particles of modern physics are not at all what we intuit when using that word. A picture often presented in physics is that of a photon, a discreet packet of energy, being absorbed by an electron and thereby converted into a higher energy state of that electron. What is really happening here? Do we really understand matter-energy equivalence? Consider that a particle itself can be converted into momentum. What is this "stuff" then?

And from the perspective of the photon, because of length contraction, there is no distance or time interval in the crossing. The source and destination electrons are, for the photon, co-located or touching. Perhaps photons aren't real particles moving through space. Maybe space itself isn't what we imagine it to be. A seeming travel of a photon, which has never been observed by the way, might be one electron directly exchanging information with another by a sort of "local" action, transferring energy from one to another.

As little as we currently understand about the deep nature of things, I'd say it is extremely premature to claim that we know that things located in space and things not located in space cannot be related. Also, the idea that there can be nothing real that isn't located in space is absurd, space itself being the perfect example. Is space located in space? No? Is it therefore unreal? The laws of physics, mathematics, and logic are all real and not spatially located.

If space is emergent, as it seems it might well be, then even the things seemingly in space aren't truly located in space. And this would cause trouble for the idea of a problem with interaction between spatially located things and things not spatially located. Instead, we'd be talking about relationships where none of the things involved have true spatial location.

And what if space emerges in mind? What if matter and space are contents of mind? Mind is then clearly not in space and yet it is easy to see that mind could be said to have some bearing on its contents. If you have trouble with this in the big, real world, consider how the argument in the OP would play in a dream. The "dream-physical", or the content of the dream world, lives in the dream world, while the mind transcends it, and yet they clearly are related. But of course, this is not truly a dualistic picture. But a kind of dualism could certainly be apparent or emergent at a certain level.

Surprised that this thread died down, oysteroid seems to have abandoned it as well.

I've been meaning to respond, but have been rather busy with some family matters. And there is so much that I feel needs to be examined/said in response to what has been said that I feel a bit overwhelmed with the prospect of responding adequately. I'll see if I can manage a decent response. Or maybe not. We'll see. Just thinking about it makes me feel tired! ;)

One thing I will say now is that since you expressed such disdain for Jordan Peterson, I've watched some more of his videos to see what he has to say. I have mixed feelings about his work. What is it about what he says that you have such a problem with? Just curious.

Agustino, I'll deal with you later... ;) I need to go for a run and do some things other than staring at this screen!

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Well, the simplest and most elegant example I can provide to you is of the Cynics. They disregarded almost off of the things you have mentioned in your post. — Posty McPostface

Regarding the Cynics, the Stoics, Socrates, Buddha, Jesus, Pythagoras, Krishna, and most other personalities that appear in very old texts, reports of their lives, actions, and words are not very reliable and tend to be full of exaggeration, fabrication, and downright deification. It was common back then for later writers to present their words as those of a dead sage. In the case of Socrates/Plato, half of what Socrates supposedly said was Plato putting words in his mouth. We don't know what these people were really like or how their ideas worked for them in actual practice. Hell, Pythagoras was said to have a golden thigh and to bilocate! Do you believe that? I'd say that reports of people completely free of the concerns I am talking about are likely equally unreliable.

Besides, didn't most of these people have a social life? And didn't they enjoy some esteem? A sense of importance? And so on? We don't hear from those who truly abandoned society and can only guess at their mental state.

Was Diogenes perfectly content in the lifestyle he chose? How do you know? I don't get the impression of a man at peace when I read about him.

Show me a real, live, happy person free of such concern due to the adoption of such ideas.

Also, these people felt they were breaking ground and found meaning in what they were doing, no? And they were engaged, trying to affect the world. They didn't withdraw and hide in their rooms!

Let's consider the actions of Diogenes, the public masturbation and pissing on people, for instance. What was that all about? Freedom from opinion? Really? He was obviously making a show of his rebellion against their norms! A rebel isn't free of what he rebels against. A conformist's behavior, thought, and appearance are a direct function of the norms of society, or of public opinion. An anti-conformist's (not a nonconformist's), or a rebel's, is still a function of public opinion, only the inverse, and so such a person is still a slave to what others think. A true nonconformist's ways would be independent of society and probably not terribly remarkable or shocking, maybe even agreeing with society in most ways, as such a person might see the sense in some of the things normal in society, language conventions for example, or stopping at red lights, or pooping in toilets. Such a person would be indifferent to what people think, not rebelling against it, not violating taboos for the sake of violating taboos. Do you think a punk rocker in the 80s in public with a pink mohawk was free of concern for the opinions of those who sneered at his appearance? Hardly. Really, such behavior is kind of juvenile, if you ask me.

I would suggest that Diogenes was probably an attention-hound! He obviously got a lot of it! He was like the shock-rocker of his day. He was a celebrity! He probably reveled in it! He even got the attention of Alexander the Great! He was about as free from opinion as Marilyn Manson!

There's a lot to address here. I've been a bit overwhelmed with things to do today. I'll try to answer adequately soon.

Agustino, it seems to me that you've misunderstood some things and made some assumptions. I guess I need to make my position more clear. And no, I am not big Jordan Peterson devotee. I am not even familiar with most of what he has said. I just ran into that video on depression the other day by chance and agreed with some of what he happened to say in that one. Aside from that, all I know of him is his panic over SJWs that I've encountered in a podcast or two. Not my thing, really.

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VagabondSpectre, you are wasting your precious time. Hachem isn't interested in the truth, as it is apparently incompatible with what he wants to believe. He has an agenda that he is going to pursue no matter what. Beating your head against this wall is only going to give you a headache. I've encountered this type of person before. You will not make any progress with him. Walk away.

This matter of that child support law seems rather simple to me. If you cause something to happen, you bear at least partial responsibility for it. Sex tends to cause births. If you have sex, you had better be ready to take responsibility for whatever might result from your action.

How does your lack of knowledge of something diminish your responsibility? Is it that you shouldn't have to pay if you aren't getting anything out of it, if you aren't allowed to participate in the child's life? Is it an exchange? Is your obligation to your children strictly a function of what you get out of your children?

If you don't want to potentially end up supporting a child, keep your sperm far away from any eggs. If you put your sperm near an egg, you have accepted the risk and should be made to bear the responsibility that truly belongs to you.

Suppose you start shooting large rocks with a powerful slingshot over buildings in random directions, not knowing where the rocks land. Now suppose that someone gets hit with one of those rocks and loses an eye and you know nothing about it. If some evidence surfaces later that connects you to this injury, should your previous ignorance of the damage you caused get you off the hook? I think not. You should be punished and made at the very least to pay as much as possible for any damages you caused.

Why is sex any different in this respect?

Too many men refuse to take responsibility for what results from their sexual activities. It reflects badly on all of us men.

If I were to be told to pay child support for a child proven to be mine, one that I had been previously unaware of, I would embrace that responsibility and more. And while I would be frustrated with the woman for not telling me sooner, I would think it right that I be made to pay.

Inauthenticity, in large part, it seems to me, comes from caring too much about what other people think of us, whereupon we internalize and behave according to values that are not really our own, or which, perhaps, we even disagree with. It is a failure of courage, self-respect, and wholeness, even a kind of weak neediness. We don't act for the sake of the good, as we see it, but rather for the sake of the approval of others. Even the fear of homelessness or being a free-loader might well be rooted in the same fear of disapproval. A truly authentic person might not care that he is seen as a loser or whatever. He isn't playing that game. Here, the practical and physical problems of survival and comfort present the real difficulties. But he might not want to be homeless or a free-loader for other reasons, perhaps seeing it as wrong to become a burden to others, for one thing. Such a person might need to work hard to become self-employed somehow, earning money in way that is in accord with his values and doesn't damage his dignity.

Maybe the world makes it impossible for someone to thrive while really attempting to live their real, examined values. Such a person, in refusing to compromise what is good, and maybe dying in the process, lives a noble life, it seems to me. Such a person is a warrior and hero in the best possible sense!

Ultimately, I think that acting with real authenticity amounts to truly acting according to your conscience, regardless of the social or even physical consequences for yourself. If you really believe it isn't right to eat animals, but you have internalized all the judgments you see in the culture around you that ridicule vegetarians, and you eat meat accordingly, you are behaving inauthentically, and you'll be unhappy in this condition. You'll be disappointed in yourself. But that's not the reason you ought to live according to your conscience. You are especially inauthentic if you have gone so far as to convince yourself that you believe and feel as they do, when you really don't.

Inauthenticity is a matter of pushing your real voice down, probably so far that you don't even know that you have one. The real you is unconscious. You live, think, believe, value, and perhaps even feel as one does, as one is expected to in your culture, in ways that your parents, your spouse, your friends, the people on TV, or whatever, would approve of. It is not that it is impossible to be authentic while also gaining the approval of others. Quite the contrary, authentic people tend to be more interesting and are often charismatic and attract admiration. It is just that the approval of others shouldn't be what determines your behavior.

This idea that there is a "real you", deep down, prior to all conditioning and approval-seeking is troublesome and possibly wrong. It seems to me that it might be the case that everything that makes you a particular individual is conditioned by an environment, be it the environment in which your ancestors evolved, or the social environment in which you develop. But I suspect that this misses something.

I tend to think that ultimately, what we are at the deepest possible level is universal, and our highest will desires the best interests of all, and is pure love. To act from the place of the True, the Good, and the Beautiful is the highest and deepest authenticity. When speaking, speak the truth! When acting, do what is right! If it is ugly to you, don't engage in it! Create real value as you best see it with honest examination. It sounds trite, but make the world a better place.

All of this requires deep and constant examination of oneself and one's motivations. Some people might think that they are saying what they really believe to be true and might be mistaken about their own real beliefs. Half-unconsciously, they might be trying to look cool or something like that, or might still be trying to find the approval of someone in their life who saw things in that way, and so on. Do I really believe what I am thinking or saying, deep down?

What could be more authentic than the simple truth?

Inauthenticity can also be of a rebellious sort, where your actions are still a function of the opinions of others, even if it is an inverse function. An anti-conformist is just as inauthentic as a conformist. Your actions should be completely independent of the opinions of others and guided by something else, perhaps the dictates of reason or higher love.

As Socrates urged, don't worry yourself about what others might think or do to you. Just concern yourself with doing what is good as you best understand it. If it gets you killed, so be it. Few things involve more authenticity than acting courageously for the sake of the highest and most beautiful things in the face of threats to your life. These things, however, must not be those things that others have pressured you to value, but those things that you truly value, that lift your heart, the sorts of things that inspire you and give you some hope for humanity and the world when you see others do them, the things that make you suspect that there might be some good in this world after all.

In other words, as Gandhi said, "be the change that you wish to see in the world."

Really, it is just another way of talking about strength of character or integrity.

But perhaps all you really want is beer and pizza, or to rape and murder small children. If you examine it deeply though, what doing nothing but eating pizza and drinking beer, or raping and murdering children, really amounts to, is this what you really want for your life and the world? Does this lift your heart? Is this what you want your existence to mean? Aren't you going to be disappointed with yourself? Listen to that deep inner voice! Act to gain its approval! But take care to be sure that this isn't just a voice you've internalized from others! Search for your real voice!

Even searching for your authenticity is to practice authenticity.

Most of all, don't lie to yourself!

What I am talking about is not being brutally honest in a way that hurts others either. Part of acting authentically, I think you'll find, involves consideration of the well-being of others. Do I really think and feel that it would be a good thing to indulge myself and say this hurtful thing? You can withhold your views while remaining authentic when it wouldn't do any good to spout them. You just need to hold on to what is true and good and not be swayed by social pressure. Keep your own voice alive, at the very least, inside your own heart and mind. Share it when the situation calls for it and it would be of general benefit, serving the good and the true and the beautiful. Telling someone you think is ugly that they are ugly is definitely not what I am talking about. That involves a very crass idea of what it means to be devoted to truth and authenticity. It may be true, but doesn't saying it conflict with the higher demands of your conscience? Is it true that I think I ought to tell this person that I find them ugly? There are different levels in such an act. There is truth on some superficial level. But at a deeper level, to say that thing is also to act according to the belief that you ought to do this action. Behind that statement is another statement: "I believe that I ought to tell this person that they are ugly." Do you really believe that you ought to, or are you lying to yourself because you want to indulge some appetite for cruelty and power over others?

But if there is something you believe is true that you also truly believe that you ought to declare as true, then say it!

Deeply authentic acts are those that you'll never regret, that'll never bring a pang of conscience. Instead, they'll make your heart sing. And you'll be forever glad that you found the courage to do these things.

Ultimately, you are the judge of yourself. Nobody else can die in your place for you. Those people whose approval you act for will never take your burden of moral responsibility upon themselves. Act according to your real, examined values and you will find your own deep self-approval.

Few of us, if any, have the courage or strength of character to do this all the time. It is an ideal that we should aim for, however.

The trouble is discovering what it is that you truly value. This requires some honest and courageous examination.

I think all of this has something to do with why Socrates said that the unexamined life isn't worth living. Consider it. If you act all your life according to values that you don't really believe in, or according to no values at all, or actually against your values, of what value is your life to you, or to anyone else for that matter? And a little examination goes a long way. It is easy to see how empty the values of your culture often are. If you live according to them, you'll only find that same emptiness.

Yes, I think technology does interfere with a proper appreciation of the natural world. It is sad that so many these days spend so much of their time texting rather than engaging with the world around them.

It is good that you explore the arts! There is much value to be found there.

As for Bergson, I haven't read more than just a tiny bit here and there. He has long been on my to-do list, but I have always felt a bit intimidated, as I have difficulty understanding what he is talking about when I do sample his work. I started to read one of his books several years ago and didn't get very far before something else grabbed my interest. But I will have to put more effort into his work one of these days! I would like, in particular, to understand his view of time.

As for Stephen Robbins, I watched the first video a week or so ago, which I saw mentioned on these forums somewhere, maybe by you. It seems interesting, but I am not sure I quite understand what he is trying to convey yet. I mean to watch more to see where his line of thought leads. I also have read part of his book, Time and Memory, and mean to finish it one of these days. Right now though, I am trying to finally tackle Kant's first critique, starting with some secondary introductory material and the Prolegomena. That reading project might take me a little while at my slow pace!

One of many baffling things about time involves the question of how quickly time passes and the idea that time cannot be its own evolution parameter. Let me explain.

Velocity is distance over time:

V=d/t

This means that as an interval of distance is covered, a certain amount of time passes. Let's say that the velocity is 10 miles per hour.

V= 10mi/1hr

Relating distance to time in this way works fine. But how quickly does time pass? If we try to express the rate of change of time this way, we seem to be trying to put time over time.

V=t/t

Time passes at 1 second per second or 1 hour per hour. This tells us nothing! And 10 hours over 10 hours equals 1 with no units, since the units cancel. No matter what time interval you plug in, you get this result. As you can see, time cannot be its own evolution parameter. It is as pointless as saying that there is one inch of distance in one inch of distance. But time does seem to pass at a finite rate! Notice that you don't experience your entire lifetime zipping by in a snap. You also don't experience it passing so slowly that it is almost stopped or actually stopped. You experience it passing at a certain rate. This rate might seem to vary a little as with time flying when you are having fun. That apparent variation isn't particularly interesting to me. What I am interested in is the strong experience that we have of time passing at a rate, even though this seems absurd when you think about it.

It might seem that the rate of time passage lies in something like the rate at which you are passing through a series of states. Instead of 1 second per second, you have 24 frames per second. But this solves nothing. Why does a second, which contains the experience of 24 frames, seem to pass at the particular rate it does? We are back to the problem we started with. This time that is passing outside the film strip that allows us to move with respect to it seems to pass at a certain rate.

Consider the following. With a film strip, we could have an animation of a moving dot and could mark our film frames with frame numbers standing for a kind of time unit. So the dot will change position from frame to frame at a certain rate with respect to the frame numbers. It might move at a rate of 1 millimeter per frame. But here, we still have no motion, real or apparent. It is just a static collection of frames. In order for you to move with respect to the film strip to see apparent motion in it, you need real time outside of the film strip. So now, as you move, you are passing through so many frames per second. You can keep doing this, removing yourself once, twice, three times, and so on, each time spatializing the time dimension. You could make another filmstrip depicting your dolly motion with respect to the first filmstrip, each frame containing an image of your dolly at a certain position along the strip. But in order to have change, you need to introduce another time dimension orthogonal to the previous one, this time real. And then you need to really move with respect to the strip. But how is this possible? Baffling and fascinating!

Thanks!

If one stares at space, maybe as an artist, space appears to take on a new experience. Artists, such as the impressionists, or maybe Da Vinci saw in space what most cannot, because the skills have not been developed.

I am an artist of a somewhat traditional sort, doing mostly painting, drawing, and a little sculpture, and I have long been very interested in space. I like to look at arrangements in space that draw attention to the spaces between things, which make the space part of the composition. Unfortunately, painting can't really do this. I also love to hike, climb, and generally spend time in nature, especially up around and on top of big mountain peaks. And what often interests me most is just the sense of space and the arrangement of things in it. The big spaces around and between rocky peaks is impressive, but so is the space in a forest or crag or in and around a plant. Architecture often exhibits space nicely as well.

It is hard to explain just what it is that I find most interesting about space.

It seems that without any objects or landscape, if you were to inhabit a completely featureless, empty space, you wouldn't notice the space. You need intervals between things and to have depth perception and the ability to move around the scene to appreciate or to even have the experience of spatial depth.

I have no idea if I notice anything about space that others don't, but I usually get blank stares when I talk about how much I like to pay attention to the spaces between and around things, so perhaps you are right.

Even in two-dimensional arrangements, I find a great deal of interest and aesthetic feeling in even a single drawn line. The gestural quality, the relative intervals between prominent features, the dynamics of the curves, the texture, the varying intensity of the line, and so on, are all very worthy of contemplation and appreciation! I quite like looking at signatures!

I love time too, and am deeply fascinated by it. Arrangements in time are wonderful. Few things I have found give me bliss like playing a good hand drum, even though I am not terribly good at it! The better I get though, the more satisfying the experience becomes.

I find movement to be incredibly blissful. I live to engage with interesting, usually rocky, terrain and to bring my attention to what I am doing, to the spaces I am moving through, to the sense of change, and to make every action as deliberate, conscious, efficient, graceful, skillful, and quiet as possible. I tend to treat it like a Japanese tea ceremony. It isn't just the space and time that I appreciate in such activity, but also how energy behaves. I like to become conscious of gravity, momentum, friction, and so on, often visualizing changing force vectors, trying to fully appreciate how it is that I manage to find purchase on small footholds by utilizing oppositional pressure, by controlling the directions in which force vectors point by using momentum, and so on. The world and my body and perceptual apparatus become a thoroughly engaging toy!

Rock climbing is one of the most aesthetically pleasing things I have found in all my years. It brings together many of the things I most appreciate: space, time, movement, interesting physics, finesse, strength, the need for courage and mental fortitude, mindfulness, the symbolism of ascent, skill, puzzle-solving, effort, breathing, a Heideggerian sort of engagement with the environment and tools, interesting knots, sun and weather, all the many aesthetic qualities of natural stone, danger, pain, and so on. Yes, pain and strain! It's part of it! Pure bliss! By far the most beautiful sport there is, in my opinion! Underappreciated! And it's not merely a sport, but also an art and a form of spiritual practice! For some, it is religion!

The point of all this is that I am indeed a great lover of experienced space, time, and qualitative physics and I am also an artist and athlete. But, is this appreciation really rare? I am not so sure. I think that mechanics and mechanical engineers have a similar appreciation of how interacting machine parts relate in space and time, how forces operate, the qualitative aspects of the functioning of a well-functioning machine, the properties and interactions of the materials, and so on, all in space and time, even if they aren't conscious of it. Athletes of many sorts, I think, are sensitive to these things. Anyone who appreciates music, nature, or art probably has it. Dancers clearly do. Skilled drivers too. I suspect that it is a fairly universal feature of human experience. I have known a few though who seem to primarily have an intelligence and appreciation for all things related to language, and who seem to have deep deficits when it comes to space, time, and intuitive physics.

Even though science comes into play in much of this, science is blind to most of what I am gesturing at. Perhaps this is the space and time, not of scientists or philosophers, but of world-engaged aesthetes! And perhaps it is these who are most in touch with what space and time really are! It is like the difference between a scholar of love who doesn't love and one who loves deeply without a great deal of intellectual analysis. Who has the greater insight into the thing in question? I guess the different approaches to these things simply offer different kinds of insight.

I get so carried away!

It seems to me that the conflict between what is being claimed in this thread to be time as conceived by scientists and time as conceived by philosophers relates to the whole problem of the objective versus the subjective. What is objective is scientifically verifiable. What is subjective is not. And the flow of time as we experience it is not objectively verifiable. Since science operationally only has access to the objective features of reality, it doesn't say anything about what we experience subjectively. Science ignores subjective time for the same reasons it is unable to adequately address the question of consciousness or subjective experience. But we all know that regardless of the fact that subjectivity cannot be objectively verified, it is nevertheless real. We know this directly. And we know exactly what it is, qualitatively, even though we can't explain it. I'd say that the same goes for time as qualitatively different from space and as something that passes, that gives us the experience of change.

The essential feature of experienced time is simply change. One thing gives way to another. There is a flow. Raise your hand and move it across your visual field. Right there, in that experience, is a mystery that science will never address.

The scientific view of time gives us a picture that doesn't give us any reason to expect an experience of change. The scientific view of time simply spatializes it. Imagine, for instance, a movie reel unrolled, the film stretched out flat on the floor. We tend to model time like this, events being spread across a spatial interval. But here, the events are simply adjacent. There is no real before or after. There is no causal dependency. There is no causality at all. Most importantly, there is no change. There is just a static set of events arranged in a sequence.

But isn't this spatialization of time just a convenient way for us to represent it in order for us to "picture" it? It allows us to draw graphs. But as usual, we should be careful that we aren't confusing the map for the territory. Real things have qualitative aspects that are not captured by simple quantity, that can't be carried by a variable in an equation. And we tend to forget that even a spatial interval as we experience it is more than a simple quantity. It isn't just a number. Like time, it has its own quality. And when we spatialize time, we are simply mapping the quantitative aspect of one qualitative feature of our experience onto another. It is essentially a lie. We are taking what is not simultaneous, what is temporally sequential, and what is not necessarily visible or visual at all, and rearranging it in our experience so that we can see it visually, and so that we can see it all at once (ignoring that we must take time to take it all in with a bunch of eye saccades). It is no wonder that our representations tend to lead us into confusions about time.

Consider how you can represent any quantity spatially, or with sound, or with color, or whatever else might come to mind. I can represent population, or luminance, or heat, or profit with a number. I can also represent any of these with a changing pitch of a musical tone. Or, to make it all available to my mind sort of simultaneously, I can draw a graph with a green line. But what is being represented is not fully captured by these representations. And heat certainly isn't green, even though profit might be!

Sound can be represented as a visible waveform. But in doing that, you've lost what most distinctively makes sound what it is. You can't experience music by scanning a waveform representation of it with your eyes. To take our spatial and mathematical models of time as directly conveying the true nature of time is a huge mistake. Our maps are useful for making predictions and for helping us to visualize and understand things in a certain way, but they are just maps.

With our scientific models, all we have are maps that show how certain things are related quantitatively. But I suspect that we discover the true nature of time in our subjective experience of it. We know it directly. We know exactly what it is when we talk about it by referring to the direct experience. And there is no way we are going to know its deep nature any better by any objective means. The objective study and modeling gives us a different kind of understanding, very much useful, but not adequate for fully capturing the thing in question.

We can see why the time of the scientists is what it is. Perhaps the time of the philosophers is what it is (it varies widely) simply because of the puzzles that subjective time poses, especially since there are such glaring differences between our subjective experience of time and the time found in our equations and graphs.

Whatever the case, even with all our modern theories, time remains incredibly mysterious. But space is no less mysterious. We only tend to fail to see it as mysterious perhaps because it is that aspect of our experience onto which quantities can be mapped by which we can most readily and immediately comprehend relationships. It is that in terms of which we seem to like to understand everything else. But do we understand it itself? Maybe, in our direct experience of it, we do. And maybe that's all there is to it. And maybe time and consciousness are like that too.

Probably, what space actually is objectively isn't even captured by our experience of it. We have our subjectively experienced spatial field, in which our other experiences are situated, and it has a certain quality of, well, what else, spatiousness! And we imagine that beyond our minds, the universe is another big spatiousness just like it, only endless. But maybe not! Perhaps what exists objectively is only quantitative. Or maybe it's something else altogether, something unknown to us. Consider the numbers that represent spatial relations in a computer game. They have no spatial quality at all in themselves. It is only when we map them onto a monitor, which maps them onto our visual field and thus maps them onto our subjective space, that we experience anything resembling space. The same goes for color, sound, and so on. There is no qualitative difference between the bits in a sound file and the bits in an image file. They only gain their differences when we map them to different sensory modalities.

The world as our minds construct it might be qualitatively and substantially (assuming the world has any substance as we tend to conceive it) very, very different from the world itself, even if there is a mapping, a kind of correspondence, between the structural features of the two.

Consider that pain is part of our experience of the world. The world as experienced has features that have the quality of pain. And pain has a quantitative aspect too, an intensity, that can be mapped and represented in other ways while losing the painfulness. But it is hard to imagine that there is anything like pain out in the world itself, existing objectively. Why should any other feature of our subjective experience be any different? Why should there be color in the world? Maybe, there is nothing like time as we understand it subjectively in the objective world.

Your idea is ambient light coming from all directions, and rays reflected by the objects, also coming from all directions, contribute to the sharpness of the picture.

That is not my idea. You've misunderstood me. Read what I wrote again and think about it carefully, visualizing what's going on geometrically.

Also, in my last post, the images near the end didn't work for some reason, so I just changed them to links. If you didn't follow those URLs earlier, click those links and see the diagrams that show why distant objects appear smaller.

This is becoming too time-consuming. And I anticipate little possibility of progress given the agenda that you are clearly pursuing.

I assure you, none of these things you are seeing here as problems are real problems. This stuff is well-understood and highly simulable.

I'm sorry, but I'll not be contributing to this thread any further.

Light that "happens to miss the rods and cones" is reused, enhancing the sensibility of the eye cells. You will agree with me that where they get reused is, from our point of view, quite random. The point is, light that is not directly reflected by an object can be used to brighten the image of this object.

I am not sure how you are picturing this exactly. Let's follow a photon into a cat eye, one that misses a photoreceptor and reaches the tapetum lucidum. When it reflects, it has a good chance of striking a rod, basically from behind, very near where it would have been recorded had it collided with a rod on the first pass. But since there is a little distance, though it is very small, between the tapetum lucidum and the photoreceptor cells, the photon might strike a photoreceptor at a very slightly different location on the retina than it would have if it had been recorded on the first pass. So, I would say that it is a tiny bit random, hence the slight loss of sharpness, not "quite random". I am wondering if you are imagining the photon reflecting from the back of the eye out further into the eye and then reflecting back again to the retina where it has another chance of being recorded. In fact, some photons will do that! But they don't offer any advantage in useful image formation. On the contrary, they just fog the image a bit. It is like the fogging of an image that you get with a camera when the sun is shining directly into the aperture of your lens. The light bounces between surfaces of your lens elements and maybe your digital sensor too and fogs your image, reducing contrast.

I don't see that there is any particular mystery here. It is just a question of where photons are going.

There is an old technique in analogue photography called pre-flashing. It consists in exposing very briefly the film to unfocused white light, and this has as a consequence that the emulsion as it were awakens and stands to attention. The real story concerns the number of ions and electrons that are activated by this pre-flash, and which get added to those activated by the subsequent shot, but details are unimportant.

On pre-flashing, or pre-exposure, from The Negative, by Ansel Adams, page 119:

"When photographing a subject of high contrast, the normal procedure is to use contracted development to help control the negative scale, but in some cases the reduced contrast, especially in the lower values, is not acceptable. It is helpful in such cases to raise the exposure of the dark (low luminance) subject values. This effect can be achieved using pre-exposure of the negative, a simple method of reinforcing low values.

Pre-exposure involves giving the negative a first exposure to a uniform illumination placed on a chosen low zone, after which the normal exposure of the subject is given. The pre-exposure serves to bring the entire negative up to the threshold, or moderately above, so that it is sensitized to very small additional levels of exposure. It will then retain detail in deep shadow values that would otherwise fall on or below the threshold and therefore not record."

Later, on page 122, Adams says:

"Pre-exposure is entirely satisfactory for supporting small areas of deep shadow, but it should be used carefully if the deep-shadow areas are large. Under these conditions it can appear as a false tonality, and large shadow areas of uniform value can take on the appearance of fog."

From a forum on the web (https://www.photrio.com/forum/index.php?threads/film-pre-exposure-post-exposure.41367/):

"...there's a certain amount of exposure that accumulates before you actually get an image. I'll use "units" of light as simple example. You expose film or paper to 10 units of light. You develop and you get Nothing. It's as if you didn't expose it at all. But if you expose the film or paper to 11 units of light, you get an image. Ten units is the threshold you have to pass to get something you can see.

So with pre-flashing, what you're doing is exposing the film (or paper) to that 10 units of light that's just under the threshold, so that any additional amount, no matter how little you add, will register. That's how you get a usable image in the low-density areas, because you've already built up that base that otherwise doesn't register.

It seems to me (in theory anyway) that post-flashing would have the same effect. But I've never tried it and I've never read a study where someone tried one vs. the other. It would be an interesting project to try. "

What about this do you find particularly mysterious?

What is important is the fact that light that does not come from or is not reflected off an object contributes to its brightness and visibility.

Imagine that you have film covered with little cells that fill with photons. These cells are black. But if they fill up with photons to a certain point, they start to lighten in increments. Lets say that 110 photons will turn them completely white. But just one photon won't start the brightening process. They can hold ten photons before starting to change color. One more will push them over the threshold. So there is a 100 photon range between white and black. There is no visible difference between a cell with 0 photons and a cell with 9, while there is a visible difference between 10 and 11 photons. If we expose this paper to light from a scene, the bright areas will easily push many cells in the corresponding region of the film over that threshold and we will see their relative differences in brightness. But darker areas that emit few photons might not. One little area might get 2 photons per cell. Another will get 9. But since both of these are still below the threshold, when we look at the exposed paper, we will see no difference between these areas, even though they had different luminances in the real scene. However, if we start by putting ten photons into all the cells right away, the situation changes. They are all already right at the threshold, so even one photon will cause a visible change. Now, those two regions will have cells with 12 photons and 19 photons, respectively, and we will be able to discern a difference between them. So we have shadow detail where we otherwise might not have.

There is a cost, however. The problem is noise. The ten units below the threshold would normally have cut off the bottom of the scale such that much random, low-level noise from various sources would not be visible on the film. With this pre-exposure, that same noise will be visible. Suppose some area of the film, even with the pre-exposure, still receives no photons from the scene because that area is pitch dark. Without noise, all the cells in that region would have ten photons and no differences would be seen between them. But the noise, which is equivalent to random extra photons here and there, will result in some of those cells holding 11 photons, some 13, some 10, and so on. This will result in visible brightness variations at small scales that are false, or do not represent actual differences in the scene. Seen from a distance, since the noise is fairly evenly distributed at larger scales, it will appear as fog.

That is also the main point I am trying to make when I argue that when we are looking at an object through a telescope, we are seeing the object there where it is, at the moment it is there. That is impossible according to Optics which says that the light reflected or emanating from the object must reach our eyes first. I beg to differ. Telescopes would be of no use whatsoever.

I am afraid I don't follow your thinking on instant light propagation at all and I don't see how it relates to cat eyes and pre-exposure of film. There is a mountain of evidence for the fact that it takes time for light to travel and that when we see distant objects, we are seeing how they were in the past. We can actually see this. Distant galaxies are younger the more distant they are. We can also measure the speed of light with various kinds of experiments. We also have delays in the signals sent using EM radiation, or photons, to and from our space probes and whatnot. There is much consilience here, which is a strong indicator that we are on the right track.

Why would telescopes have no use if they don't allow us to see things as they presently are? It is much better to see Pluto as it was hours ago than to not see it at all! Surely it is good to be able hear someone from across the room even though it takes time for the waves in the air to reach my ear!


I didn't address this earlier:

One of the most obvious but still unexplained phenomenon is that objects appear smaller with distance.

This is easy to explain. Once again, just consider the geometry. This says all that needs to be said on the matter:

link


Another:

link



Why complicate things, trying to find mystery where there isn't any? There are plenty of deep and real mysteries, consciousness for example, existence itself for another.

Hi Hachem,

I think it might be helpful if we make more clear how a pinhole camera works and how a lens works. Let's model this with simple rays first, without thinking about waves.

First, the ideal pinhole. Why is an image formed on a plane behind the pinhole? Imagine that you are inside a dark room looking through a small hole out onto a street scene. The hole is very small. The wall in which the hole resides is very thin, infinitely thin, in fact, so that this is an ideal hole, not a tube, so that rays can pass through at angles approaching parallel with the wall. Now, just move your head around while looking through the hole. If the hole is small enough, you only see a small point of color. Suppose your head is in such a position that you see a point of red on the door of a parked car. Move your head much lower and you might see a point of blue from the sky, since you'll be looking up through the hole. The important thing here is to see that any given point in space is only receiving light from one point in the scene, found by tracing a line from that point in the room to that point in the scene.

The image that is formed on a screen inside the dark room behind the pinhole is simply a consequence of the above. Each point on the screen is receiving light only from one point in the scene. And the reason for this is nothing other than that the pinhole is restricting the light arriving at each point to light from a particular point in the scene. If you enlarge the hole, the image becomes brighter but less sharp. If you enlarge the hole all the way, or remove the front wall altogether, the screen will be broadly illuminated by the scene. Why? It is because the light arriving at a given point on the screen is coming from multiple points in the scene, all over the scene in fact. There is light from the sky, light from the car, light from the fruit stand, and so on, all adding up at that point on the screen. And light from a particular part of the car, if the surface is a diffuse reflector, is scattering to multiple points on the screen. The larger the aperture, the less the light on any given point on the screen is restricted to just one part of the scene. So, being less restricted, there is more light, but less sharpness.

Consider what happens if you move the pinhole up or down or left or right in the front wall. The image on the screen will change. The perspective changes. The point where your head needs to be to see the door on the car outside will change. Now imagine what would happen if you poked a second hole in the wall. You'd have two overlapping images. Poke a third hole. Poke a fourth. More light is reaching the screen, but you have multiple overlapping images, and so you are losing clarity. Light from bright parts of one image are getting to dark parts of another. Keep poking holes all over the wall. Pretty soon, you can't make out a clear image at all. Keep poking until the wall is totally gone.

When you have just one pinhole, it is like you are simply excluding all the other possible pinhole images. When you have no wall, it is like you have all the possible pinhole images at once.

Why is the image from a pinhole upside down? Imagine moving your head to look through the hole to see different parts of the scene again. You must put your head low to see the sky through the hole. You must put your head high to see the ground near the front wall outside. So the image projected onto the screen, the image plane, will be upside down. Light from the sky strikes it low. Light from the street strikes it high. Light from the right side of the scene (as you look out) strikes the screen on the left, behind you. So all is flipped over, as we would expect from our observations.

"Did you know that the size of the diaphragm has no influence whatsoever on the field of view?"

The reason for this can be seen by considering the above thought experiment. Making the hole larger or smaller does not change the fact that you can see through it from any angle behind the wall. The field of view captured in an image on the screen is given, as we would expect from the geometry, by the distance between the screen and the hole, not the size of the aperture.

"instead of thinking of rays that somehow know whether they will be dealing with mirrors or pinholes/lenses, "

There is no need to even consider the possibility that rays know anything about what they are dealing with. All we have here is simple geometry and selection. What I mean by selection is how a camera, whether a simple pinhole camera or one with complex lens, restricts the light arriving at a point on the screen to light coming from a point in the scene. The setup is selecting for certain rays. The problem with many optical path diagrams is that they don't show the rays that are excluded or not of interest and so they sort of wrongly imply that light is choosing to go through a pinhole or lens. Consider our pinhole room again. If light bounces off of the red car door towards the wall with the hole in it, it doesn't aim for the hole. It isn't specially directed at all. Where the light goes is simple geometry. There is much light in the scene that isn't going through the hole. The hole simply restricts the light arriving at the screen to that light that is passing through the hole. All the other light is blocked by the front wall around the hole. That's why the outside of the front wall is illuminated by the scene. Imagine it like a rain gauge catching only certain water drops. No drops are aiming for the rain gauge. The drops that end up in it are there only because the rain gauge was placed in the path on which they would have travelled anyway.

One important thing to notice about the pinhole is that if we move the screen, the image plane, nearer to or farther from the hole, the image is always in focus. It just changes size on the image plane, getting smaller as the image plane gets nearer the hole. This is because the rays describing, say, the car, are spreading outward from the hole. The further away the image plane, the more the rays have spread apart. This is just geometry.


Next, let's consider the lens. How does it focus light? Once again, let's leave waves out of our model for now. Let's just allow that a lens bends light paths according to certain rules. If light passes from one medium into another, its angle changes by a certain amount that is a function of the angle of incidence. We don't need to get into the math or Snell's law. This diagram will suffice:



Rays perpendicular to the surface of the lens are not bent. Rays entering a denser medium at an angle are bent, and are bent more the nearer that angle is to parallel to the surface of the lens. Rays entering a less dense medium are bent the other way.

The production of an image with a lens is a little more complicated. Let's image that we have the same setup, except that instead of a pinhole, we have a larger lens at the same location. But realize that regardless, we already and unavoidably have a pinhole camera at work here. Its aperture is the outside edge of the lens. If we remove the front wall and have only a lens, we will not do a good job forming a clear, contrasty image. This is because we would not be excluding the light that is not passing through the lens. We want to exclude that light first of all. So once again, we have this selection going on, this reduction of the light that is arriving at the screen.

The advantage of a lens over a tiny pinhole is that it allows us to get a focused image with a larger aperture. How does it accomplish this? Imagine the door of our red car. In a very small area of that door, there will be light reflecting out from the imperfections in its surface at a wide variety of angles, not all of which would pass through our tiny pinhole. Since the rays spread out from that small region with distance, the larger our aperture, the more rays pass through, hence more brightness on our screen. However, as we saw earlier, with just a pinhole, as the hole gets larger, the image becomes less focused, because each point on the back screen is receiving light from a larger variety of points in the scene, those seen through the hole from that point. So the light coming from a certain point in scene is not restricted to arrival at only one point on the screen. And light arriving at any one point on the screen is not restricted to light from only one point in the scene.

The lens serves to focus that unfocused light. Imagine the many rays emanating from one tiny region of the door of the car spreading out in all directions. The larger our lens, the more of them arrive at the surface of the lens. The lens then bends those rays such that they all arrive at a single point in space inside our large camera. But this focus point is not necessarily on the screen! It depends on the angles of the surface of the lens, its curvature, how close it is to the screen, and so on. If we move the car farther away from the lens, the angles of the light rays arriving at the lens surface change so that the focal point is further behind the front wall.

What we want, ideally, is to capture as much of the light as possible coming from one point in the scene and direct it to exactly one point on the screen. This is the purpose of the lens. Whether it is a pinhole or a lens, the purpose is to make sure that only light from one point in the scene is arriving at only one point on the screen. But because a pinhole is so small, only a small portion of the light emanating from a point in the scene goes through it.

The problem with the lens is that the focal point, as we pointed out earlier, moves deeper into the room if our car moves further away. So with any given placement of the back screen, only parts of the scene at a certain distance are in focus, only those whose focal points happen to coincide with the screen.

What is depth-of-field? Why does it happen?

Remember that with our pinhole, the smaller the hole, the sharper the image is, with the cost of reduced brightness. And also remember that the image is always in focus no matter the distance of the objects in the scene or the back screen. The lens, on the other hand, produces an image that is only focused at a certain distance. Suppose we have the screen, lens, and car arranged such that the car door is in focus on the screen. If we move the screen back a little bit, the image becomes slightly unfocused. The more we move it back, the more unfocused. This is because the light rays are spreading out from the focal point.

To understand this, it helps to play with a simple simulation. Please try this if it will work on your setup:

link

Or this image might help:



If we move the pencil in the above image away from the lens a bit, the sharp image projected to the right of the lens will move closer to the lens. So you'd need to move your projection screen, film, or sensor closer to the lens to get a sharp image. The closer the pencil is to the lens, the further from the lens the screen needs to be.

Now consider that with a lens combined with a changeable aperture, we are combining the principles of the lens with the pinhole camera. The aperture is just a large pinhole. A large pinhole by itself won't produce a sharp image. The larger the hole, the softer the image. Consider the geometry of many light rays spreading out from a point in the scene and arriving at the opening of a large aperture behind a lens. The rays come to a focal point as usual with a lens, but if restricted by a smaller aperture, the circle of out-of-focus light arriving at the screen when the screen is further away than the focal point will be smaller, meaning the image will be sharper. And the angles at which the light from the focal point to the screen spread out, being restricted, will spread out less at a given distance. So the smaller the aperture, the sharper the image, though the image won't be pin-sharp except when the screen and focal point coincide. But that circle-of-confusion might well be small enough that you can't tell the difference.

Using a nice simulator (link), I made these four images (click image below to enlarge if it shows up small) to show wide and narrow aperture with the screen beyond the focal point at two distances to show how, with a larger aperture, the circle of confusion grows more rapidly as the screen is moved away from the lens. The lens here is an ideal lens represented unfortunately as that vertical line segment with arrows on the ends. The point from which all the light rays emanate can be though to be any point in the scene from which light is being emitted, say a point on the car door.



Because of the wave-like properties of light, other factors come into play like diffraction, which limits sharpness with small apertures, but that is another topic altogether.

"Another problem with aperture is that the extra light that gets through the lens does not necessarily come from the objects depicted in the image. Think of the tapetum lucidum, the shining layer at the back of a cat's eyes that makes them shine in the dark. It reflects light back onto the retina and makes it possible for the cat to see better in the dark. It is apparently the same principle as a larger iris, a way of letting more light through. But is this extra light reflected off the objects we are seeing, or simply ambient light with no specific target?"

What extra light that gets through the lens doesn't come from objects depicted in the image? With a less than ideal lens, like a real lens, you get lens flare and whatnot. But the phenomenon in a cat's eye you are talking about is just light, focused as usual by lens and iris, that happens to miss the rods and cones striking material slightly beyond the rods and cones and reflecting back toward the rods and cones, where it has a second chance of being detected. This increases the sensitivity of their eyes. But some of that light misses the rods and cones even on the rebound and manages to exit their eye, where you see it. Not all the light entering their eye is absorbed by the rods and cones. In our case, the material beyond the rods and cones, instead of reflecting the light back for a second chance, absorbs many of the photons that miss the rods and cones. There is probably an advantage in visual acuity here. Cat eyes probably sacrifice sharpness for light efficiency. Those reflecting photons may reflect at such an angle that they hit rods or cones slightly off the proper location, thus reducing sharpness.

"If that light came from the objects themselves we would be confronted with the previous problem: larger objects would be more hindered by smaller apertures than smaller objects, and should therefore appear relatively darker. "

I don't understand your thinking here at all.

"Here is the problem: the image shown by the projector does not come from the light, even if we assume that once the light goes through the slide it gets colored just like the slide before it finally hits the screen. "

What happens with a projector is as follows. Light comes from a lamp and is sent through a condenser lens and then passes through the film. Let's stop here for a moment. What is happening at the film is once again nothing but restriction of the light. The film is basically casting a shadow. The light coming through the slide does not "get colored". The light before the slide is already composed of photons of many different wavelengths. The slide filters that light. A portion of the slide that allows red light to pass but not blue or green is simply absorbing the blue and green photons at that point while allowing the red ones to pass on through. The slide is clear in some places, allowing all colors of photons, which results in white light being perceived on the screen. After the light passes through the slide, it is focused by a lens onto the screen, which is white to reflect all colors and has a diffuse texture so that it will scatter light in all directions. So the photons that make it through the filter (the slide), are directed by the lens to specific locations on the screen, from which they then are reflected, whereupon your eyes receive some of that light and you see the image.

"In the case of a camera or our eye, we would have to accept the idea that the image is somewhere on or in the lens, and that light from the outside shines through it and projects it on our retina or the sensor area. But how did the image get in the lens if not carried by the light rays?
Okay, maybe it was carried by the light rays reflected off the objects, and once it was in the lens extra light shone through it?"

Why this extra image that gets "in the lens", through which light then shines? No such thing is needed or happens. What we have is just photons passing through air and lenses and being recorded somewhere. The image that results is quite simply a consequence of pure geometry, as we've been describing.

Of course, waves, diffraction, interference, quantum mechanics, and imperfect lenses and so on complicate all this. What does it mean, for example, for a photon to "pass through" a lens from a QM standpoint? That gets more involved. But the essential geometric ideas expressed here should go a long way toward clarifying matters.

The issue of mirrors is simpler still. Just picture light emanating from a point in a scene, reflecting from the mirror according to the law that angle of incidence equals angle of reflectance, and you are all set.

Why is the image from a mirror right-side-up? Just think about it. You are standing in front of a mirror, very close to it. Light from your forehead is going to bounce from the mirror up near your forehead, not down near your feet. In order for the mirror image to be upside down, the photons would have to be teleported to the other end of the mirror. A photon would leave your forehead, strike the mirror up near your forehead, and then jump down low inside the mirror, and then come out by your feet. Obviously, this doesn't happen! And why is the mirror image, while right-side-up, reversed left-to-right? Same reason. The light from your right hand is hitting the mirror near your right hand and reflecting back out from the same location. The image is directly reversed in a sense, but not by any flipping. Rather, it is reversed in depth because of reflection.

The reason pinhole and lens images are upside down I addressed above. It is all simple geometry and all makes sense if you draw out the light paths.

Phew! That was long! I really hope it helps!

"“[The Native Americans] didn’t have any rights to the land and there was no reason for anyone to grant them rights which they had not conceived and were not using… "

What an odd line of thought! Did she think that rights only belong to those who properly conceive them? If we were to make that into general policy, imagine the consequences! No rights for the unintelligent. No rights for children. No rights for the elderly who have lost their faculties. Of course no rights for animals. And so on. Only people with the right philosophy would have rights. And how would that be justified?

Or what about the "which they ... were not using" part? If you have a guitar but never use it and I am a musician without a guitar and would make better use of it, does that give me a right to take it from you? You weren't using it, after all! I don't think this idea is consistent with some of her other thinking. Basic property rights seem pretty important to her.

It seems to me that, if we were to accept the imperative she seems to assert here, some sort of argument based on it could be made for socialism's redistribution of property. It could be argued that the wealthy aren't making proper use of their resources and that better use of them might be made if the community takes them and spreads them around. After all, a wealthy person might be hoarding the best musical instruments in a vault while many talented musicians might lack instruments altogether! Maybe "civilization" in some way depends on musicians having access to the means of realizing their potential! If civilization itself is the purpose here, it might be that redistributing wealth would best serve that end.

How are we to determine what proper use amounts to?

Suppose a wealthy man is using his money simply to stack bricks as high as possible as a symbol of the importance he ascribes to himself, so that all can take notice of his superiority and accomplishment, in a display of his high status and superior abilities. And suppose human beings all around this man are starving to death. Surely, they could make better use of his resources! But that depends on the values. One set of values might say that human life has intrinsic worth and that many human lives are far more valuable than an obscene monument to this guy's ego, something with no function for society other than to serve his sense of superiority and make others feel small, or perhaps to inspire them.

Another set of values might consider these people worthless, or even to have negative value, by virtue of their very inability to feed themselves. Such people are perhaps an offense to the sacred potential of humankind! Some might see a kind of nobility in such architectural gestures, in the greatness of spirit displayed by the man who can master the world around him and build such noble monuments, which announce the presence of a superior human type, some great end-in-himself who justifies all the means that support and stand beneath his exalted existence. Such a man and his grand gestures might justify all the universe! Some might see this as having greater value than the scum moochers who would unjustly take a piece of what he has amassed through the application of his intelligence, strength of character, and sheer will! It all depends on where we put the value.

Personally, I find such disregard of wider human life, this selfishness, to be quite ugly, not a beautiful or high gesture at all.

And is something like this not basically what many wealthy people do with their resources? Don't they build monuments to their egos? Don't they display big status symbols? And don't they do this in the face of much human suffering that could be alleviated with even a portion of the resources they command? I understand that many do in fact invest their money in, and seek further profit from, projects that ultimately benefit everyone--the building of a network of railroads, for example--but if the end to which all this is a means, if what justifies it, is universal benefit, this certainly wouldn't be compatible with Rand's values. And if universal benefit is taken as the prime directive, systems other than capitalism might be argued for, and property rights might even be sacrificed if it would serve the greater good.

It seems that Randians are doing something problematic if they justify what she advocates by saying that it benefits everyone. They are justifying her system under the values of those her system openly opposes, and whose values she rejects. They are, it seems, measuring the worth of the system under a set of values incompatible with those involved in that system.

So what is it that justifies her way of doing things? Some idea of the value of greatness and power? It isn't exactly clear to me.

But who is to judge how a person chooses to use their property?

Conquest is a form of theft, plain and simple, as is all predation, even in the animal world. One agent, be it a nation or an organism, eating another is stealing what that other agent has labored to build. It is stealing what most belongs to that agent, its very self, its very existence, its very substance. But such theft might be justified under certain systems of value. We might, for example, consider human beings to be such a superior way of arranging matter that this justifies the killing of lower animals. Perhaps humans have more value than pigs. Thusly, we justify our theft of what a pig has labored to build in its very body. We might similarly justify a mighty civilization conquering weaker and less sophisticated peoples and taking their resources in order to raise the status of more material, to increase value. Regardless, I don't think theft is compatible with other regions of Rand's thinking, though I am no expert on her thought.

My guess is that she basically considered the Native Americans to be something less than human, and that's really what made it okay in her mind.

And did the Native Americans really not conceive of any rights? They may not have put their feelings into exactly the words of European enlightenment thinkers, but I'm pretty sure they had a sense of rights of some sort, and some basic sense of justice. I think all people feel that something unjust is happening when people with weapons invade their homes, kill them, take what they hold, and so on. Isn't some sense of rights intrinsic to this feeling of being wronged? Does it need to be written out in a formal declaration?

Hey Wayfarer! Thanks. I don't know if I'll be too active, but I might pop in now and then.

I’ve always been rather curious myself as to whether the blatant incongruity of both the attitudes of Left and Right towards 'Abortion and Capital punishment'

I've long thought that the positions held by each end of the political spectrum have less to do with reason and principle than with gender instincts. If you realize that the right wing is driven by primitive masculine values and the left by primitive feminine values, all becomes more clear. Most of the standard political positions of the two wings make more sense in this light. Thinking about evolved primitive gender roles and the instincts associated with those roles is a taboo subject in this politically correct age, but it can yield some insights.

Why limit identity to either a single moment or a single worm? And if it is a single moment, why the extent of one brain state, spanning a brain? Does it have any temporal span? Do we have a measure of one Planck time? If no temporal span, why allow spatial span?

The way you are restricting identity seems awfully arbitrary. It would seem less arbitrary to expand it to the universal or atomize it all the way to something like a single bit of information or a smallest possible particle of matter for Planck time. Any notion of identity having some finite span, be it temporal, spatial, or something else, is problematically arbitrary. Why so much? Why so little? Is there some kind of magical boundary around what you consider yourself to be? Can it grow or shrink?

And then you have the mystery of why you happen to find yourself being this part of things and not another. And if it is possible for you to not be most of the stuff in the world, why is that non-identity so incomplete? Why not slip off the world altogether, being completely non-identical with all of it, such that the world is entirely other and you don't exist at all? If it is possible for you to fail to be most of the world, how did you manage not to fail to be part of it at all?

I think it far simpler to think that there is exactly one single experiencer for which everything is immediately present. Identities only seem restricted because the information isn't fully integrated between all the parts of the world. For example, even though that which experiences everything going on in your brain is also that which experiences everything going on in my brain, no memories from your brain are found in mine, and so over here, I don't "remember" having been over there.

Imagine that there is an amnesiac named Joe who has only a small bit of functional short term memory and no long term memory. We put him in a room with a chalk board and have him record what he observes in that room on that board. If we ask him what he has experienced, he reads back what he has written on the board. If we move him to a second room with another board, he will record different experiences there and have no access to the memories on the board in the previous room. So despite the fact that it is the same guy in each room, he has no idea about his other life in the other room. He can't integrate information between the rooms. But this doesn't mean that we are dealing with two separate selves.

While I don't think that we are some detachable perspective thing that moves between brains, our situation is somewhat analogous. The true experiencer is everywhere at once and possibly at all times. But information integration comes in clusters inside this experiential field that are fragmented to varying degrees.

Memory constitutes a sort of information integration across time, between brain states. The present contains information about the past. Perhaps just as experiencing visual redness is what it is like to integrate information in a certain way, experiencing the flow of time is what it is like to integrate temporal information in a certain way.

One interesting thing to note is that there is an asymmetry in apparent identity across time that results from limitations in the availability of information. I feel myself to be the same person as my past self, but I don't feel myself to be identical with my unknown future self in the same way. It is a little like my failure to realize that I am also you. I have almost zero information about myself as an old man. The uncertainty is huge. But I have lots of information about my past self earlier today. And the story I tell myself about myself, from which I construct my falsely limited identity, comes from precisely this limited information that I have access to. Culture also plays a part in telling us how we ought to think of ourselves as distinct individuals. The idea of a soul has particularly strong influence on this self-conception even if we've abandoned traditional religious views.

And perhaps the reason we feel time to be flowing "forwards" is just a result of this information asymmetry. I remember the past, but not the future. The present brain state contains something of an echo of a previous one, but not of the next one.

If we could somehow integrate all the information, we would realize that we are everything. I strongly suspect that if we were to link up our brains in a highly integrated way, similar to the level of integration in a single brain, we wouldn't feel ourselves to be two separate selves in close contact, each with access to the other's brain. Rather, we would feel ourselves to be a single bound mind in the same way as we feel as a network of 100 billion highly integrated neurons spanning a single brain. There are no homunculi sitting in each of our brains that would find themselves as co-pilots in the newly joined larger brain..

The thing is, we know that we have experience that is bound and has at least some span across part of the universe, including many parts. Otherwise our experience would be atomized into tiny experiential fragments, something like the mind dust that William James described. These fragments couldn't have any particular experiential character due to their lack of integration. Seeing red, for example, requires not just detecting red light, but also at the same time registering that neither green nor blue are detected and integrating all this. A red sensing cone alone cannot distinguish between pure red light and white light. And when we see white light, we don't see red. The very visualness requires further integration as well. So you coudn't have an atom of red visual experience. You need span and integration in order to have red visual experience.

And I think we can be sure that we span multiple moments in time. Otherwise, I don't see how we would have any sense of change. So I think we can rule out the atomized end of the identity spectrum. And anything else besides universal identity is hopelessly arbitrary and fraught with problems.

All puzzles of identity are solved in one fell swoop when you realize that you are everything. You just have to accept that you have many windows through which to look out on yourself, each with a limited view. And you may never tie it all together such that you realize you are looking through them all at once.

And you are nothing like a worm. As far as life on this planet goes, you are the whole tree of life, branching, branching, branching. Remember that in block time, this body of yours is literally physically sprouting from that of your mother, and hers from her mother, and hers from hers, all the way back. Why draw some imaginary line between yourself and your mother? And of course, you aren't just the biology and you aren't limited to this planet. Further, you might even inhabit all of the branches of Everett's Many Worlds in all of the many universes produced by eternal inflation!

I'm late to the discussion and haven't read the entire thread. Forgive me if I am raising a point already made.

"If you could press a button that would turn everyone into brains in vats living the best possible lives imaginable would you do it?"

Would each person be isolated or would they inhabit, via an avatar of some sort, every other person's virtual world? In other words, will they be networked? Will the other people be real or "non-player characters" driven by an AI and lacking subjectivity? If each person would be isolated in a virtual world of their own, then to press the button would be to condemn them to a largely meaningless existence devoid of the possibility of true encounter and morally significant action. And such a life cannot possibly be the "best possible life imaginable".

I'll put aside my small quibble that any virtual world must be far less rich than its host world, which would nullify any possibility of it offering the best life imaginable. If everyone would inhabit a common world and interact directly and share experience and affect one another, then I don't see much problem pressing the button. I don't see how it would be existentially much different than the world we inhabit now. The other people in the world would be real. There would be someone else, an end-in-himself/herself, on the other side of each encounter, someone who must experience what is done to them. The world would have depths. Of course, this challenges the notion of "best possible life imaginable" that most probably have in mind because it would be possible for people to treat each other in unloving ways and to obstruct their will.

Also, I suspect that most people, in dreaming of some scenario that would constitute "the best possible life imaginable", are envisioning a life without suffering, death, struggle, poverty, limitation, and so on. It seems to me implicit in the question that such a life would be one in which each person has limitless power, resources, access to aesthetic experiences, fine surroundings and possessions, and so on. In my view, such a life would be pure fluff, like living in a kitsch painting, empty of real and substantial life, completely hollow and superficial. It would be strictly masturbatory. Despite all appearances, a deep desolation would permeate everything. By far the greatest impoverishment in such a life would be the absence of other subjects with whom one might enter into the Ich-Du. This "life" would be always strictly in the mode of Ich-Es.

It would seem that to make life in a virtual world substantial and deep, you'd have to bring into it the very sorts of conditions that we find ourselves confronted with in this world that we would presumably be trying to escape by creating such a virtual world. So what would be the point in leaving the real world?