Don't shoot the philosopher. He's doing his best. Although he's not always very good. — David Mo

I'm not shooting the philosopher. Having studied a lot of philosophy in my day, I've seen what I feel are some ways that it can go wrong, and have expressed my opinion on some practices that can be used to improve it.

What I have suggested is not out of the mainstream of contemporary philosophical thought. In fact, it is how I was admonished to think by Judith Jarvis Thomson in Philosophy 101 when I violated this "best practice". Her advice has stuck with me all of these years.

|>ouglas

Ah I see now! You are smarter than the even the greatest minds of our generation. Forgive me for ever having doubting you.

|>ouglas

So, |>, do they have a table in C++ , in Java, and in all other languages, for ALL imaginable non-reducible fractions of integers? — god must be atheist

No, there are algorithms to determine the greatest common divisor and least common multiple of two Natural numbers.

|>ouglas

Bring them to the same denominator? Like humans? — god must be atheist

Precisely so!

|>ouglas

You remember right, but that wasn't at issue - we've both acknowledged that this is the case. My point is that relativistic time is not identical to physical time (the time that physical clocks measure). — SophistiCat

Personally, I would not refer to time as measured by a clock as "physical time". I would call it "clock time" or some such. Time as measured by a clock is stochastic. It only follows from the second law of thermodynamics, which is not fundamental law. It doesn't even make an assertion that is true in all possible worlds that have the same fundamental law as ours. And that have a Bug Bang.

There is a possible world where my fair coin has always come up heads, even though I have tossed it a quadrillion times. Likewise, there is a possible world in which my pocket watch has always run backwards, without being broken in any way.

In my eyes, "physical time" must not be stochastic. (Unless it turns out that the universe is stochastic all the way down.) Consequently, Relativity provides for two directions of time. This is the only "physical time". There are two directions of physical time that point in opposite directions, and we label one the future and one the past for our convenience. But in perverse situations, and after the heat death of the universe, these labels may not be perfectly appropriate.

Why is this important? To bring this back to the original topic, a common argument for the B-theory and against the A-theory is that the theory of relativity, though it may not rule out the A-theory, does not offer any support for it either. The A-theory requires additional assumptions that are not part of SR or GR. The implicit thesis here is that we ought to base our theory of time on the theory of relativity and nothing else. But this thesis is weakened if the identity between relativistic time and physical time is weakened.

The fact that clocks are not reliable in all possible worlds, or after the heat death of the universe leads me to exactly the opposite conclusion: We should not be making any profound metaphysical conclusions at all based on clock time. We should stick to relativistic time. Labeling one direction of time the future and one the past is just a convenience for discussion, in that we are usually talking about situations that have a readily fathomable entropy gradient.

|>ouglas

Douglas, Where did ZelebG go? You see what you've done? We quibbled, and ZG took the opportunity of the moment that we weren't watching, and he ran away. — god must be atheist

A fringe benefit for sure!

|>ouglas

Perfectly true. But the numbers will be thus represented as long as a program is run written in that particular programming language. If you run a different program, written in a more conventional programming language, that does not have that feature programmed into its structure, then you lose accuracy of rationals with infinite repetitions. — god must be atheist

I don't understand your argument. We should not be making any metaphysical conclusions based on how computers are typically used today.

As for the "conventionality" of programming languages, all of the most popular programming languages in use these days have libraries for doing math with rational numbers (and never having to convert them to floating point). These languages include Python, Java, C++, etc.

|>ouglas

Once you enter into a variable the value of 1/7, and you use that variable's value in calculations, you will immediately lose the perfect accuracy, as the calculations storage go on binary code representation. — god must be atheist

This is not true. A programming language that supports doing mathematical calculations with rational numbers will typically not force you to ever convert the rational number to a floating point number. The program can run from beginning to end using only rational numbers, and can consequently produce results with perfect precision and accuracy. (Assuming that the numbers being represented are accurately represented as rationals.)

|>ouglas

P.S. Here is an example of a library for Python that lets you do just this:

https://www.tutorialspoint.com/python-rational-numbers-fractions

Now this is funny. Don't you see that is exactly what I'm saying? All I have to do is set my arbitrary resolution to planck scale and define the arbitrary given size as that of the universe to match Tegmark. — Zelebg

Yes, I have agreed as much. The problem is that Tegmark is making a contentious premise in his argument, and therefore, we cannot be sure of his conclusion. All we can say is that if his premises are right, then his conclusion seems to be right, but if his premises are wrong, then we can have no confidence in his conclusion.

|>ouglas

In triary computers, yes, 1/3 could be digitized, but 1/2 could not. You can't escape this problem with any digital system. — god must be atheist

I certainly don't agree that with Zelebg, but this assertion of yours is wrong. Computers can and do represent rational numbers at times with perfect accuracy. This is done by representing them as a pair of integers, rather than in a "floating point" format.

|>ouglas

So, for some arbitrary given resolution and some arbitrary given size of an object, such that it maximally occupies the whole screen, say 800x600 resolution and passport style photographs of human faces - there exist a finite number of possible human faces for that particular specified size and resolution. Yes? — Zelebg

Sure, but so what? Nothing interesting results from this.

If you want to get to the interesting question, let's take Max Tegmark's argument that in our Hubble Sphere, there are only a finite number of possible states. (Our Hubble Sphere is the area of space that is causally connected to us. I.e., it's radius is defined by the farthest distance from us from which light from the Big Bang has reached us.)

If the universe is flat, then it contains an infinite number of Hubble Spheres, and consequently, if you were to be able to travel at faster than the speed of light, and you went far enough, you would eventually come to a Hubble Sphere that is in the same state as ours. Consequently, this is a way in which there might be parallel "universes" that are identical or very similar to ours.

This argument rests on the premise that all the physical features of the world are quantized, however. And this may or may not be the case. If it is the case, then Tegmark would seem to be correct. If it is not the case, then his argument fails because it is based on a false premise.

|>ouglas

I have an SB in Philosophy. I never studied Philosophy of math. (Though I did take a class on Paradox and Infinity taught by George Boolos.)

In my education, I was always taught that numbers are real, abstract entities. When this was asserted, the professor would typically insert some caveat about how not everyone views numbers in this way, but it was easier to conduct philosophy if you made this assumption. So please let's "bracket" skeptical worries about this, they would say.

I'm sure that when I wrote a paper, I could have adopted either position as a premise without argumentation, and received no red marks, as long as I was consistent wrt to this in my argument.

Personally, I see no good reason to reject numbers as being real, abstract things. In fact, it only seems to make one's life more difficult. There are important questions in Philosophy that I actually lose sleep over, and I don't see how being an anti-realist about numbers is going to help me answers those questions. In fact, it would only seem to make my life more difficult in that regard.

If I'm going to be an anti-realist about numbers, why not also be an anti-realist about chairs, for instance. There are physical things that correspond to our human conception of chairs, but are those things really chairs? Or are they really only just bits of space-time quantum probability wave configurations that we have arbitrarily decided to lump together in a way that does not amount to chairs being "real".

I suppose if I were a "real" philosopher, I might be interested in the intricate minutiae of all the myriad positions and arguments that one can make about exactly it means to be "real". But personally, I guess I'm just a dilettante who is more concerned with the answers to very important questions, like,

(1) "Will that internal Star Trek transporter leave me alive? Or will being transported kill me?" (Wanting to know the answer to this question is actually why I started studying Philosophy, and on the first day of Philosophy 101, Judith Jarvis Thompson pointed at me at the beginning of the class, and asked me why I was here in a Philosophy 101 class. I was too embarrassed by the reason I was there to answer her. Little did I know at the time that this is actually a topic of serious philosophical debate!)

(2) Are p-zombies possible, and if not, what explains the fact that no amount of perfectly good reasoning can convince me that they are not? Well, maybe this really means that interactionism is true and p-zombies can't exist, but interactionism just seems way too problematic.

(3) Why is boiling live babies to death something that I should not do? It seems like an indisputable fact that this is true, but all roads of argumentation that would lead to this conclusion seem to be based on very tenuous premises.

(4) Why is there something rather than nothing? It seems to be incredible that there's all this stuff, rather than nothing at all. (Except for numbers and the like.)

So, all in all, how would rejecting the reality of numbers help me in answering what is really important?

|>ouglas

That is not the answer, just refusal to accept the premise of the question — Zelebg

You made an argument with a false premise. Consequently, you have not proven your conclusion. This is Logic 101.

and is beside the point since the bottom resolution can be fixed to arbitrary size and precision. Say, human faces. My monitor can show every possible human face at least down to a scale and precision of an electron microscope. Therefore, there is only a finite number of unique human faces. Yes?

No. Faces can differ in details that are smaller than the resolution that can be captured with an electron microscope. Also, different faces, even if they look the same in a particular pair of photographs, can move very differently from each other, which can completely alter our perceptions of what those faces look like.

|>ouglas

Let's just say you implied that time has a direction, or that there is an arrow of time, if you will. How is this consistent with your agreement that "time doesn't flow at all"? No flow should entail no direction. — Luke

Does space flow towards the north pole? And yet there is a spacial "arrow" that points towards the north pole.

And the state of things that are "here" is different for every point in space that lies between me and the north pole.

In eternalism, "now" is like "here", only for time, rather than for space, and the "past" (the direction towards the Big Bang) is like "south" and the "future" (the direction away from the Big Bang) is like "north".

Now why would any of this commit me to whatever your concept of "flow" is? I have my own notion of "flow", but it only entails that for adjacent points in time, we have some power of calculation about how the physical state of the universe will differ between those two points in time. These powers of calculation come from our understandimg of physical law. And what we will calculate, and what the actual states will be, is unaffected by eternalism vs presentism.

|>ouglas

On every page there is a description of a single particle, where it is, what is doing at the given time. — Zelebg

You can't fit all the required information about even a single particle on any finite-sized pixelated page because some of the values associated with the particles would be represented by Real numbers not Integers or Rationals, and a Real number contain an infinite amount of information in it. I.e., you cannot encode an infinite amount of information on a page that can only hold a finite amount of information.

|>ouglas

Ugh, why do I even waste my time on this... — SophistiCat

You are clearly a glutton for punishment!

You can bring a horticulture, but you can't make him think.

|>ouglas

You implied that time has a naturally preferred directionality when you stated that we remember the past and not the future, which "follows plainly from thermodynamics and information theory." I don't see how you can consistently argue both that time doesn't flow and that time has a preferred directionality. — Luke

I have not said that time has a "preferred directionality". I have said that you can remember the past and not the future. Which direction is "preferred"? The directions just have different properties due to the laws of thermodynamics. Laws which are not affected in the slightest by eternalism or presentism.

Repeat after me: FOR EVERY POINT IN TIME, THE PHYSICAL STATE OF THE UNIVERSE AT THAT POINT IN TIME IS IDENTICAL UNDER ETERNALISM AND PRESENTISM.

Until you can acknowledge and comprehend this irrefutable fact, you will be forever lost.

If nothing moves or flows, then how do we get from one brain state to the next? — Luke

Who says that we "get" from one brain state to the next? At time T1, you are in brain state A. At time T2, you are in brain state B. For any given time Tn, physical law tells us what brain state you will be in. And that brain state will be the same brain state whether eternalism is true or presentism is true.

Are there any theories of how our brains work (e.g. to produce our minds and represent things) which do not require motion? — Luke

Repeat after me: FOR EVERY POINT IN TIME, THE PHYSICAL STATE OF THE UNIVERSE (INCLUDING YOUR BRAIN) AT THAT POINT IN TIME IS IDENTICAL UNDER ETERNALISM AND PRESENTISM.

|>ouglas

The thinkers of the past often said things that were clearer and more profound than today stars of philosophy. — David Mo

That may very well be true, But that doesn't mean

(1) That I have the time or interest to pursue their particular theories. I already spent enough of my life trying to figure out how it is true that Santa Claus wears a red suit when Santa Claus doesn't exist.

(2) That the jargon they used is the one true jargon of philosophy.

Ordinary language is specially confuse when using the word "facts". For example: "mathematical facts" and "a matter of fact". Therefore a more analytic "jargon" is needed. — David Mo

All I am asserting is that when you answer the type of philosophical conundrum that is of interest to a layperson, your answer better have actually answered the intended question and not a different one. I think that it is common for philosophers to do so by becoming so entrenched in their own jargon that they no longer even understand lay usage of words.

For an example of someone who is very careful not to make this mistake, I highly recommend Parfit's book "Reasons and Persons". In it, he answers the age-old question, "If I get into that infernal Star Trek transporter, when I am transported down to the planet, will it still be me? Or will I have died, and the person on the planet will just be some poor sap who is deluded that they are me?"

Parfit answers this question deftly, while being careful to preserve the meaning of the question asked, and not answer a different question by sloppy substitution of jargon for lay usage.

|>ouglas

This begs the question. Why assume that 'time flows' from ordered to disordered states? Because that accords with our perceptions? It remains unexplained why there should be a preferred directionality to our perceptions of temporal flow if nothing really moves. — Luke

I don't assume that time flows from ordered to disordered states. In fact, since I have stated that eternalism is true, I have stated that time doesn't flow at all. This doesn't mean that our brains can't represent time as flowing.

You seem to constantly willfully ignore a fact that I have repeatedly stated: SInce physical law is the same under both eternalism and presentism, our brains are going to be in the same states either way for any given point in time. And because they are going to be in the same states either way, our minds are going to represent things the same way regardless of whether it is eternalism that is true or presentism that is true.

The question that needs to be answered it not why does time flow in a certain direction. The question that needs to be answered is why does time seem to flow in a certain direction. The answer to that question is because our brains represent time as flowing in a certain direction whether or not there is actually any flow.

All I have to do is explain why our brains represent things in a certain manner, and then I have answered why things seem to be a certain way. The only way that things can seem to be, is the way in which our minds represent them.

Why does the world seem to be three dimensional, rather than nine dimensional, for instance? The world may be nine dimensional. That is what is predicted by string theory. The short answer is because our minds represent the world as three dimensional. Because our minds represent the world as three dimensional, the world seems to be three dimensional.

Is it your assertion that our brains can represent things as being one way, and yet it could seem to us that things are different from how our brains are representing things? If that's your assertion, I'd certainly like an account of how this is possible and how it would work!

|>ouglas

But the two do not mean the same thing. — tim wood

I'v presented more than a bit of evidence that they do to the intelligent layperson. I've also proven that they are also used this way by at least enough philosophers to have this usage documented in the SEoP.

You: "Oh, sorry! You didn't go to college, or at least my college, so I thought you were stupid, or at least ignorant. Let me correct myself. What I really meant was...". — tim wood

You are being complete disingenuous. It's you who started with the name calling.

|>ouglas

I consider Miller's article to be an even-handed presentation of the issues, and you might recall that it was introduced in the OP, not by me. Call it "argument from authority" if you like, but I am simply attempting to have it recognised that Eternalism entails a motionless world. — Luke

I think the issue here is that the terms like "motionless" and "static" are ambiguous and emotionally laden when talking about something like eternalism. Let's consider a film reel of the best car chase ever filmed. It's so perfect that no decent aficionado of films could disagree with this.

Now consider that in one sense, this film reel is static. It never changes. In another sense, it's full of change and motion. One can imagine that the film editor working on it, if they were really good, they might not even ever have to watch the scene to edit it. Their sense of film editing might be so refined, that they can just fathom all this motion in their heads from individual frames, while they cut and paste bits of film around.

Now imagine that there might be aliens who love human films. Imagine that they don't need to see the movie projected in real time in order to enjoy our films. They just ask for our films as mp4's and their brains are sophisticated enough to decode the mp4's and model what is going on in a film. And boy do they love this car chase! Even though they have never watched it frame by frame. They just absorbed it all at once. But their brains can model all the exciting motion that is going on the film without having to have actually viewed anything moving.

Or you might imagine the same thing about our greatest novels. All sorts of things might be happening in them, right? But no. Nothing happens in a novel. They are static. They don't change. Well, it depends on what sense of the word "happens" and "change" you are using when use these words to describe the novel.

Again we can imagine aliens, or some super-smart person, who doesn't have to read a novel in order in order to appreciate it. You can give them the pages in any order, and in their heads they can reconstruct the proper order for the pages, and appreciate the entire novel in an instant.

Is a great novel static? Or is it dynamic and full of exciting and interesting events?

You tell me!

Now consider that a human life has some similarities to a novel. If eternalism is true, one can view it as either static, or as very dynamic, depending on what sense of the words you are choosing to use when you describe it.

In any case, even if you just consider the above to be a bunch of incorrent blathering, my account has addressed all of Miller's stated worries about eternalism. I can't go over each sentence at the moment, but let's take just one:

why do we have such a different relationship with the future than with the past

One hugely important reason for this is that we can remember the past and not the future. This is true in eternalism just as much as it is true in presentism. It follows plainly from thermodynamics and information theory.

|>ouglas

Except that there is actually no motion according to Eternalism. I would imagine that it's much easier to explain why we perceive motion if there actually is motion than if there actually isn't. My point, again, is better expressed by Kristie Miller: — Luke

I don't think you understand how philosophy works. You pointed me at something that putatively needs to be explained, and I provided my putative explanation. It is now your job, should you chose to accept it, to provide your putative explanation for why what I argued is wrong.

Instead of doing this, you just repeat the same thing, as if I have said nothing.

Also, you seem to be arguing from authority that Miller is right and consequently I am wrong. This is bad philosophy for several reasons. I'm not going to get into all of the reasons for that, but I will point out that you seem to think that Miller is on your side. At least from this article, she is not. The book from which this chapter was selected seems to be a textbook that a Philosophy professor would assign their students to read. Such treatises are often specifically designed leave certain questions unanswered, in order to allow for debate in the classroom and for students to write papers where they have the leeway to chose which position they want to argue for.

I will point out that Miller also describes plenty of problems for presentists, and you are cherry-picking your argument from authority by ignoring the fact that Miller has more objections against presentism than she has against eternalism. This probably just follows from the fact that the orthodoxy these days is that eternalism is the true account. (I don't know this for sure, but that's the impression that I got from attending some Philosophy conferences at MIT where everybody but me was actually a professional philosopher.)

|>ouglas

P.S. It's likely the case that your actual worry is about phenomenal consciousness. If that's the case, I am quite sympathetic. I am not a physicalist with respect to phenomenal consciousness myself, and I'm sure that feelings similar to mine are one of the reasons for the spotlight theory being prevalent to whatever degree it is, but despite many years pondering and studying the issue of phenomenal consciousness, I feel no closer to an answer today than when I started.

Right. You mentioned your boss. I understood it was a reference to his master in the degree. I could have used your boss's opinion that you quoted. But it doesn't matter. — David Mo

My boss has a PhD in linquistics. I was just using him as another piece of evidence in how the word "fact" is used by a layperson. In general, linguists are only concerned with how language is used by laypersons, and not how grammarians, etc., think they should be using language. (Though I'm sure that there are also linguists who study the jargon of subcultures, etc.)

Here's a classic: Carnap, Rudolf: "Formal and Factual Science" (1935): — David Mo

Well, that's pretty old. Almost all of my Philosophy education (other than Philosophy 101) was oriented around engaging in current debates. (Or rather in debates that were current at the time.) The purpose for this, I suppose, is that you couldn't write papers by simple regurgitation. You had to think for yourself and present your own unique arguments.

Consequently, I may have lost some historical perspective. On the other hand, in the little Philosophy of Science that I did study, these distinctions from 1935 were no longer being made.

but leaves engineers or biologists indifferent. — David Mo

This would also leave me indifferent, even though I have a deep interest in Philosophy. But mostly only how it relates to Philosophy of Mind. And maybe to ethics. But I didn't study ethics deeply.

This said, I do have something of an interest in Kuhn's revelation that science doesn't work nearly as cleanly as one was taught in high school. But I haven't done any deep studies in this area of philosophy.

If the use of jargon bothers you, you're lost in philosophy — David Mo

The use of jargon doesn't not bother me in the slightest. As long as the users of it are clear that they are using jargon, why they are using jargon, use it clearly, and don't slily substitute it for lay usage when answering a philosophical conundrum that has been expressed in lay language.

|>ouglas

The problem that I see here is that there is no inherent connection between the direction of time given by the time coordinate of the relativistic spacetime — SophistiCat

It's been a long time since I studied special relativity (we spent several weeks on it in Physics 101), but IIRC, relativity doesn't provide a forward and reverse direction of time. It just provides two directions of time, and they are symmetric.

Sure, there's talk about the "future" direction and the "past" direction, but it seems to me that that is just so that you can do thought experiments and the like about causality. Those two directions, for the purpose of thought experiments, are specifically chosen to match with thermodynamics. But other than for the purposes of thought experiments involving causality, which presupposes well-behaved thermodynamics, special relativity IIRC is completely agnostic on which direction is the future and which is the past.

|>ouglas

I consider the moving spotlight view to be a hybrid of Presentism and Eternalism, since it contains all times/events (Eternalism) plus motion (Presentism). If you remove the spotlight, you remove the motion, and then you need to account for the appearance of motion. This is exactly the problem for eternalists. — Luke

The appearance of motion is something that is represented in your brain. Where else would there be an appearance of motion? Since physics is the same under presentism and eternalism, your brain is going to represent the same things under either presentism and eternalism. Consequently, if your brain represents the appearance of motion under presentism, it will do so under eternalism, and vice versa.

As for aging, this is yet again a physical process that works exactly the same under presentism and under eternalism. Under eternalism, you can think of your life as a film roll, and at one end of the film roll you are a newborn baby, and at the other end of the film roll you have hopefully died happily at the age of 107 of natural causes in your sleep. In each frame between your birth and death, there will be evident an incremental bit of aging.

|>ouglas

I find it very strange that at MIT no one has explained to you the difference between factual and formal sciences — David Mo

I've never heard of such a distinction. Are you talking about the difference between theoretical and experimental science? I am quite familiar with that distinction. I didn't study much philosophy of science, however, other than Kuhn.

And pure and applied mathematics, of course. — David Mo

At MIT, it was never my experience that there was some sharp dividing line between the two. At least at the undergraduate level. Applied mathematics was just pure mathematics that you might need in the course of being an engineer, and other pure mathematics might have no applications yet. Or none that would be of interest to a typical engineer.

Engineering departments also had their own highly developed math, such as Laplace transforms and Z-transforms, that the math department did not seem at all interested in. Though when I talked to mathematicians about this sort of math, when I described it, I was told at times that I should feel privileged to have learned such interesting math, even though it was not the sort of the math that they themselves had ever studied.

I keep wondering what your teacher has to say on the subject. What a pity. — David Mo

Which teacher? I got my degree a long time ago. I.e., 1988. Though I continued to take some classes at MIT into the late 90s. Some of my professors are now, sadly, dead. E.g., Judith Jarvis Thomson and George Boolos. And Ned Block moved to NYU.

Regarding reading a paper that uses some particular jargon use of the word "fact", I have no problem with jargon as long as it is explained, used consistently, and understood as jargon and not lay usage. I have never claimed that the way that I have been using the word "fact" is the one true usage of it. Only that it is the typical lay usage of it, and the way that it was generally used in my education. It is also supported, as I have pointed out numerous times, in the Stanford Encyclopedia of Philosophy, as a common usage in Philosophy.

So, I have no clue why anyone would disagree with anything I have said. Everything I have asserted is completely innocuous. I have never said that anyone else is using the term "fact" incorrectly. I have only asserted that I am not using the term incorrectly. Since the SEoP backs me up on this, please take any further objections to them.

|>ouglas

GR doesn't know anything about entropy - it's not part of the theory. — SophistiCat

I understand this. The second law of thermodynamics is not even fundamental law. It is stochastic.

They have to limit themselves to GR's coordinate time, which increases monotonically (in simply connected topologies), but in an arbitrarily chosen direction. — SophistiCat

For an eternalist, I should not think that this is a problem. Time is symmetric with respect to fundamental law. (Modulo Cronin and Fitch. It's a bit hard to know what to make of this at my level of understanding, but I'm going to put it down as "annoying detail" until someone informs me otherwise.)

Since time in fundamental law is symmetric, it has no forwards or backwards. It just has two different directions that are equivalent, except for the fact that they point in opposite directions. Only thermodynamic tells us which direction is foward and which is backwards. Were one to travel through a strange region of space in which the entropy gradient changed directions, this would no doubt be problematic in terms of how we normally conceive of causality, etc., but fundamental law, including GR, should have no problem at all with it. In GR, time still has two directions, and there is no difference between the two directions, other than which one is heading toward increased entropy. GR and the rest of fundamental law doesn't care about this, however.

Or at least that's how I understand things.

Therefore, if it is possible for the entropy gradient to reverse itself along the length of one worldline, then a relativity fundamentalist faces a problem, because her theory of time is not sensitive to this change. — SophistiCat

I don't see the problem. There are two directions of time. Neither of these directions of time ever changes. The only thing that might change is which direction of time is pointing towards greater entropy could change. But the direction is not changing. Only what is in that direction might change.

Now I certainly agree that having the entropy gradient reverse directions on you has all sorts of potentially unsavory and weird consequences, which, I suppose is one reason that some people think that this will go away when GR and QM are unified.

Others just think that universes where things get too weird in this regard, are just very improbable universes, so we're not likely to find ourselves in one. E.g., typical time travel paradoxes that are not logically impossible. E.g., a being from the future brings you back via a wormhole the solution to clean fusion energy production. In the future, the only reason that clean fusion energy exists is because you published a paper on how to achieve it. The invention of clean nuclear energy production came into existence without any inventor. (Well, I'm sure I'm now belaboring a point that you already fully understand.)

There's nothing in GR that precludes this. But amongst the solutions to the equations of GR, the solutions that include such strange occurrences are much less prevalent than the number of solutions that don't include such strange occurrences. (Yes, I know blah, blah measures on such infinities don't exist, blah, blah. Understanding any of that or how to resolve these objections is beyond my pay grade, but I assume that there is some answer that is something along these lines. I.e., my friend who is a UPenn professor with a PhD in number theory doesn't seem worried about this kind worry, despite the fact that I don't think he can answer the worry about measures in infinite spaces. In fact, he's fully signed onto Tegmark's MUH.)

|>ouglas

Another possible response from eternalists is the "spotlight theory". It's in Miller's article, so you can read more about it there.

Under the spotlight theory, such an eternalist will say that time is like a movie reel. It's all there all at once: past, future, and present. Only there's a spotlight that runs down the movie reel illuminating one frame at a time, in chronological order.

Most eternalists will say, "Exactly! Only there's no need for the stupid spotlight."

If you want a version of eternalism that works for you, start with the spotlight theory. And then convince yourself that you don't need a spotlight. Or remain committed to the spotlight if you wish. It's no skin off of my teeth either way.

|>ouglas

"the eternalist owes us an account of why it should seem that there are such features [of change, temporal flow] in the world when there are not." — Luke

Eternalists have such accounts: Time is real. It is locally ordered. (I word it this way just to account for Special Relativity.) For every point in local time there is an immediately past point in local time and an immediately future point in local time. People, and other representationalist systems, such as fancy computers, can represent the past and the future relative to the point in time where the person or computer is located. They can understand the laws of nature well enough to make certain predictions about the future points in time from the past points in time. They can record information about the past in their memories, etc.

It's no big mystery. The only reason that Miller even says this is because she seems to be trying to write a balanced exposition of the two positions without forcing anyone's point of view. (I assume that this article is for a textbook for students who might then write papers where they argue for one of the two positions.) But if you read her article, you will have noticed that she has many more critiques about presentism. Would you like me to throw them all at you and force you to answer them?

|>ouglas

You asked how things like bodily functions can work under eternalism. They work under eternalism for the same reason they work under presentism. I.e., physical law (and hence biological law) is the same with either!

|>ouglas

You appear to be claiming both that things can change and evolve over time, but also that nothing changes? — Luke

You just don't understand these metaphysical distinctions. As I mentioned physical law is identical under both of them. If you don't believe me, write to Miller and ask her yourself. She'll tell you just what I have.

PHYSICAL LAW IS IDENTICAL UNDER BOTH ETERNALISM AND PRESENTISM.

Repeat that to yourself 1,000 times until you understand it. There's no point in having a discussion when you don't understand the basics of the distinctions that are being made.

|>ouglas

Then I take it you agree with all of the following: — Luke

Yes, I do.

|>ouglas

My apologies for the lack of clarity. I guess what I'm getting at is that we have dynamic accounts for how memory and other bodily functions work (neurons fire, light enters the eye, blood circulates, etc), but I don't see how this could work in a static world. — Luke

You need to read Miller again. Presentism and eternalism are metaphysical theses. They do not affect physical law. Physical law is exactly the same with either metaphysical thesis. If you understand how physical law works under eternalism, you understand how it works with presentism and vice versa.

Physics itself is completely agnostic about whether eternalism or presentism is true. Though I'd hazard a guess that most physicists would side with eternalism.

(Actually, what I said above is not quite right about Physics being agnostic, since certain aspects of Special and General relativity present serious issues for presentism. Though a presentist can fudge answers that I find completely unsatisfying and ad-hoc. Also the fact that physics is almost completely symmetric with respect to time is another problem for presentism. At least in my opinion. If presentism were true, I think it would be very surprising for the laws of nature to be time-symmetric.)

|>ouglas

I'd be happy to read any articles by these other professors that provide an alternate definition of Eternalism, if you can direct me to them? — Luke

There is no need. I have read the article by Katie Miller and she has done a perfectly good job of explaining all the issues. I agree with everything she says, except for one paragraph:

For the eternalist, the key challenge lies in explaining temporal phenomenology and
in explaining the apparent directionality of time. There has been significant work in
this area, but questions still remain: why do we have such a different relationship
with the future than with the past: why is it that effects typically precede their causes
when the laws of nature are symmetric: why do we remember the past, but not the
future

I don't believe that anyone on the planet has offered a satisfying explanation for phenomenal consciousness, so eternalists are in no worse shape here than anyone else.

As for why we remember the past and not the future, this follows plainly from thermodynamics. When a computer program runs, it follows the laws of thermodynamics. Computers, like people, remember the past and not the future. This fact is true in either eternalism or presentism because these different metaphysical theses do not at all affect physical law.

|>ouglas

No offence, but I think I'll take the word of the associate professor over yours. — Luke

No offense, but I think that you have taken what has been written at a superficial level and haven't done the work to actually understand it.

If you do understand it correctly, you should probably make yourself aware that this is a philosophical debate that has raged on for decades at least, and there are many full, tenured professors who agree with me. And in fact, some of those full tenured professors taught me what I know about the subject. Which was at MIT, which is considered, last I checked, to have the fourth best Philosophy department in the world.

So if you don't want to take my word for it, take the word of some tenured MIT full professors.

|>ouglas

I don't have time to read Miller right now. I have actual work to do, which is towards trying to cure cancer. So please forgive me if I'm erring on the side of brevity at the moment.

I did quickly read that staticism is the thesis that the present doesn't move. I find this to be a bit misleading with respect to eternalism. In eternalism, all times are the present in the sense that all places are "here", if that's where you happen to be.

There's nothing in eternalism that precludes things from evolving over time, since in eternalism there is definitely time, and at any given point in time, there are future times and a past times. And things will be different in those future and past times. Hence things change as time changes.

|>ouglas

My apologies for the lack of clarity. I guess what I'm getting at is that we have dynamic accounts for how memory and other bodily functions work (neurons fire, light enters the eye, blood circulates, etc), but I don't see how this could work in a static world. — Luke

I don't really know what to say. It works exactly the same. The only difference is whether you consider the past and future to not exist, which is presentism, or whether you consider that everything that ever happened to still exist and everything that has yet to happen to already exist. If you believe this, then you are an eternalist.

Other than these differing metaphysical theses, which may not be at all provable either way, everything remains the same.

|>ouglas

You’re defeating your own argument Douglas. I can certainly sense some accuracy in that last sentence though! — Alcyone7

How am I doing that?

|>ouglas

Okay then, how are events 'made present' for a cognitive entity, such that they have a relative past to remember? I'm finding it odd for an eternalist to be using such presentist terms. — Luke

I don't understand your question. In an eternalist world, I exist right now, as I am typing this, and I can remember events that happened before right now and I can't remember events that are going to happen in an hour.

There is also a version of me existing who resides at a point in time 15 minutes ago. That version of me can't remember what I am typing right now, because that is in his future, but he can remember my previous response to you.

|>ouglas

What is the eternalist account? — Luke

The eternalist account is that at every point in time, a cognitive entity can remember events from the past and cannot remember events from the future, relative to that point in time. (Modulo certain time-travel scenarios, which are very unlikely in reality.)

|>ouglas