You seem to be operating under the impression that the "Boltzmann Brain" is "a brain and just a brain experiencing is space." It isn't. It is just "physical system capable of producing consciousness." It says absolutely nothing about brains floating in vacuum having experiences.

You seem to be operating under the impression that the "Boltzmann Brain" is "a brain and just a brain experiencing is space." It isn't. It is just "physical system capable of producing consciousness." It says absolutely nothing about brains floating in vacuum having experiences. — Count Timothy von Icarus

:up:

I think it would help to look at the nature of necessity. If you want to say that X is necessary to Y, you can't argue that it is because nobody has ever seen the two separately. Just because it's never happened before doesn't mean it won't happen tomorrow.

Stating that X is necessary to Y is a strong assertion that would require showing why they can't exist separately. In the case of consciousness, that would require a working theory of consciousness. That doesn't exist right now. All you can do is say that you doubt this or that about consciousness. Leave necessity to trivial issues.

Sorry, I wasn't trying to be comical or ridiculous. I was just saying that my experience doesn't have to reflect interaction with my environment

I should be the one to apologize, I just meant to add some rhetorical flourish, not impune anything.

I was just saying that my experience doesn't have to reflect interaction with my environment. I have long had a recurring dream about a house that opens up into another house. Though I've experienced being in this weird house multiple times, it doesn't exist. My environment at the time was my bedroom. It appears that experience was generated by my brain.

Funny enough, I've been working on a novel that involves people stuck in an infinite house.

Anyhow, I get what you are saying. I would just frame it differently. Your enviornment isn't irrelevant to your dream. Obviously if we filled the room with anesthetic or poison gas instead of air it would change the experience. Rather I would frame it like this: "our experiences don't always correlate with the enviornment the way we think they do under 'normal' conditions."

It's possible to have convincing dreams, false memories, hallucinations, etc. These still involve the environment, but they don't have the connection to the world that we think obtains when we "see an apple" or "taste a lemon."

Of course, even in such "normal" instances of perception things that don't exist are phenomenologicaly present to us. For instance, we might see smoke on the horizon as a sign of a fire that has already ceased to exist. When we read fiction the signs on the page of our book direct our awareness to things that have never existed. Dyadic mechanistic accounts of nature seem to always have a problem with this sort of thing, hence the divorce of "mental" and "natural" or subject and objective world.

Hm, lion...nino...What is that, little lion boy? — Kizzy

You had to reduplicate the -n- there to make the joke work. But not too far anyway.

The question of whether Boltzmann Brains have ever or will ever exist seems ancillary though. Michael simply misunderstands the concept if he thinks it provides an example of "brains alone producing conciousness in space." The concept isn't even specific to "brains," it's an argument about the minimum that is needed to produce any given interval of experience and how this smaller system is more likely to emerge from random fluctuations than any larger system. It is entirely silent on "what is the minimum physical system required to produce x interval of experience," since this is simply not a question that is addressed by the concept.

However, we can certainly extrapolate from biology and neuroscience that a Boltzmann brain would need to exist in some range of ambient temperature, atmosphere, etc. in order to produce anything like say "5 seconds of human experience."

However, we can certainly extrapolate from biology and neuroscience that a Boltzmann brain would need to exist in some range of ambient temperature, atmosphere, etc. in order to produce anything like say "5 seconds of human experience." — Count Timothy von Icarus

I read the last page but maybe I am still getting half-way through the chat. We had a very long conversation about Boltzmann brains here, but the fluctuations could possibly produce 5 seconds of human experience, and it would produce it infinitely many times, as the probability is non-zero in an infinite period of time. Contrary to that, there would be some upper limit to how much mass a quantum fluctuation can produce by how much time, but no such limit is known by our physics.
And it wouldn't necessarily need to create those 5 seconds of experience, but a consciousness with the memories of those past 5 seconds. Though of course that relies on a view of personal identity that puts a substance moving forward through each infinitesimal point of time, but that is not a weakness in my view. It is a scientific version of Last Thursdayism.

It is just "physical system capable of producing consciousness." — Count Timothy von Icarus

Such as a brain:

The scenario initially involved only a single brain with false memories, but physicist Sean M. Carroll pointed out that, in a fluctuating universe, the scenario works just as well with entire bodies, even entire galaxies.

…

… human brains are vastly more likely to arise from random fluctuation …

…

Boltzmann-style thought experiments generally focus on structures like human brains that are presumably self-aware observers.

Although this seems to be moving beyond the relevant point, which is that colour percepts are the product of neural activity in the visual cortex. This neural activity can be caused by optical stimulation by light, e.g. when awake, or by other things, e.g. when hallucinating or dreaming. We don’t need to posit some additional mind-independent colour; we already have a parsimonious account of colour perception consistent with the scientific evidence.

Or, are they just allowing us to see the colors the fruit had all the time.
— Richard B

This makes no sense. Colours aren't mind-independent properties. — Michael

It makes sense: a colour is the disposition of a pigment or light to systematically cause the experience of the colour.

The experience exists in the mind, but the colour that you experience exists regardless of being experienced.

Hence the world is coloured even when no-one is there to experience it.

I haven't said that mental phenomena aren't just particular brain states. I'm not necessarily arguing for any kind of dualism. I'm leaving that open. Maybe pain just is the firing of C-fibers, as Churchland argues. Maybe colours just are the firing of V4 neurons.

Regardless of what mental phenomena are, pain and colours are mental phenomena; they are not mind-independent properties of fire. — Michael

I believe sense can be given to saying colors are brain-independent and brain-dependent. For example, I am looking at a multi-color object in front a me and report out the different colors. Next, I put on some glasses and now the object appears black. I call this part of the process of seeing colors, brain-independent. Another example, I have an operation on my brain where the doctor removes the neurons associate with color perception. I look at that multi-color object again and it is black. I call this part of the process of seeing colors, brain-dependent. I think you would agree to this.

That said, this brings up the interesting idea of whether black is a color or, from a scientific point of view, the absence of color. If it is an absence of color, like science says, are you compelled to admit that black is a mind independent property of an object? But how could you, can't I dream of black objects which is mental phenomena? Alternately, can't I order a can of paint with the color black contra science?

Language, it can be so messy.

the colour that you experience exists regardless of being experienced — jkop

The surface layer of atoms with a configuration of electrons that absorbs certain wavelengths of light and re-emits others exists regardless of being experienced.

But this isn’t colour. Colour is the mental percept created by neural activity in the visual cortex. That is how coloured dreams, coloured hallucinations, synesthesia, and variations in colour perception are possible.

Referring to mind-independent objects as having colours is a relic of naive colour realism, the mistaken view that either confuses colour percepts for being mind-independent properties or falsely believes that, in the veridical case, colour percepts resemble mind-independent properties. Our modern scientific understanding of the world and perception has corrected us of this misunderstanding.

Things are black when they absorb all (visible) frequencies of light, and so do not re-emit any (visible) frequency of light.

As such there is no (visible) light to stimulate the rods and cones in our eyes, and so the V4 neurons are not fired, and so no colour percepts are produced.

It’s certainly not the case that black is some mind-independent property of objects that is seen by the absence of (visible) light. That just makes no sense at all.

But this isn’t colour. — Michael

I didn't say that. I said that the pigment and the light have the disposition to systematically cause the experience of colour. This means that the colour experience arises when an animal that has the ability sees the pigment or light, while the colour is a property of the pigment or light in the form of a disposition.

See the SEP-article on color, in particular on color-dispostionalism.

If you don't distinguish between experience (i.e. event in your brain) and colour (i.e. object of the experience), then you can't distinguish between veridical experiences and hallucinations. How could any animal have survived on this planet if they were only hallucinating and never saw objects and states of affairs? Arguments from illusion or hallucination suck.

The existence of its atoms and their propensity to reflect light at certain wavelengths. — Michael

How do we perceive this propensity? Do we just assume our perceptions are externally caused?

Since all perceptions are subjective responses, you can't claim any property to exist objectively, except to just say the perceptions must be being elicited by something.

That is, an atom has no particular shape, size or color. It just makes me see what I think to be a chair.

I may be channeling Wittgenstein (I can hear the collective groans out there), but doesn’t the fact that we can have this discussion at all mean that we are all participating in the same form of life – a form of life called, “perception” – and, along with it, a certain inherited background of mutually agreed-upon “rules” (for want of a better term)?

Specifically, there is something we all have as organisms – including sensory organs, nervous systems and brains – that allow us to interact with the world. And then, of course, there is the world (and everything in it) that we interact with – e.g., red pens and berries. This is a given, because without this commonality, we would be unable to have any kind of meaningful discourse – whether we are in agreement or not.

At the very least, this inherited background (or foundation) gives us the ability to enter into a discussion about how perception happens, whether it is veridical or not, how to distinguish “real” perception from hallucinogenic ones, what we experience in dreams, etc. And importantly, we agree on the terms we use in our discourse – otherwise, we wouldn’t be able to discuss this topic intelligibly. Again, such unquestioned, inherited foundations are part of everything we talk (and argue) about.

Consider an experiment involving a beaker of liquid. The beaker is the means by which we have access to the liquid so that we may gain knowledge about it – i.e., the liquid’s chemical composition, volume, weight, and so on. The beaker makes the liquid accessible and measurable. Otherwise, the liquid would just be random spillage on the floor, making it impossible to accurately access it for observation. However…

…the beaker itself is not part of the discussion. Where the beaker was manufactured, what packaging materials came with it when it was shipped, whose fingerprints are on it, etc. – none of this comes into chemists’ discussions about the experiment. In short, the beaker’s existence and reliability are not drawn into question. In fact, they can’t be. Otherwise, we would be plunged into an infinite regress of epistemological skepticism, where even the skeptic’s arguments become absurd.

Damn… where was I going with all this?!

As such there is no (visible) light to stimulate the rods and cones in our eyes, and so the V4 neurons are not fired, and so no colour percepts are produced.

It’s certainly not the case that black is some mind-independent property of objects that is seen by the absence of (visible) light. That just makes no sense at all. — Michael

Yet, I can see black objects. I can pick out an object that is black from other objects that are colored. Why can't we say it lacks the property of color? What makes less sense is to say I pick out a black object because it has no mental percepts. I pick it out because it was black.

If you don't distinguish between experience (i.e. event in your brain) and colour (i.e. object of the experience), then you can't distinguish between veridical experiences and hallucinations. How could any animal have survived on this planet if they were only hallucinating and never saw objects and states of affairs? Arguments from illusion or hallucination suck. — jkop

In the case of colour there is no such thing as veridical. It’s not “correct” that light with a wavelength of 700nm causes red colour percepts, such that if a different organism with different eyes and brain sees a different colour in response to 700nm light then they are seeing the “wrong” colour.

I didn't say that. I said that the pigment and the light have the disposition to systematically cause the experience of colour. This means that the colour experience arises when an animal that has the ability sees the pigment or light, while the colour is a property of the pigment or light in the form of a disposition. — jkop

We can use colour terms however we like, but when we ordinarily use them we are referring to colour percepts, not an object’s disposition to reflect a certain wavelength of light.

When I look at the photo of the dress and describe its colours as white and gold, the words “white” and “gold” are referring to colour percepts, not the pixels on the screen emitting certain wavelengths of light, and when someone else looks at that same photo and describes its colours as black and blue, the words “black” and “blue” are referring to colour percepts, not the pixels on the screen emitting certain wavelengths of light.

If the words “white”, “gold”, “black”, and “blue” were referring to the pixels on the screen then the very claim that some see white and gold and others see black and blue (when looking at the same screen) would make no sense at all. Yet it is both coherent and factual.

Yet, I can see black objects. I can pick out an object that is black from other objects that are colored. Why can't we say it lacks the property of color? What makes less sense is to say I pick out a black object because it has no mental percepts. I pick it out because it was black. — Richard B

I have repeatedly drawn a distinction between the adjective “red” and the noun “red”.

We can use the adjective “red” to describe a mind-independent pen that has properties that are the cause of red colour percepts. But the noun “red” refers to that colour percept, not a mind-independent property of the pen.

How do we perceive this propensity? — Hanover

How do we perceive a fire’s propensity to cause pain? By putting our hand in the fire and being hurt. In the case of colour, we look at the pen and see red.

Do we just assume our perceptions are externally caused? — Hanover

I think it’s a little more than an assumption. Perhaps it’s the most rationally justified explanation.

Since all perceptions are subjective responses, you can't claim any property to exist objectively, except to just say the perceptions must be being elicited by something. — Hanover

We can claim anything we like. Some are true, some are false, and some may be more justified than others.

I think it’s justified to claim that mind-independent chairs exist but that mind-independent pain doesn’t, and most would agree. Clearly there’s just less of a consensus regarding whether or not colours are more like chairs or more like pain. I think modern physics and the neuroscience of perception shows them to be more like pain.

That is, an atom has no particular shape, size or color. It just makes me see what I think to be a chair. — Hanover

That would certainly be the Kantian view, and I’m sympathetic. But I’m not arguing for anything that extreme. I’m only arguing that colours, like pain, are a mental percept.

We can use the adjective “red” to describe a mind-independent pen that has properties that are the cause of red colour percepts. But the noun “red” refers to that colour percept, not a mind-independent property of the pen. — Michael

So "black" is an adjective and a noun because not only does it describe the property of the object (absorbs all colors of light) but it picks out the object from other objects of color (There is no color percepts to refer to). But if "black" is adequately described in this way, it is hard to see why we could not extend this to "red", "blue", etc... as well. There is no practical reason to refer to "mental percepts" at all, or for that matter, it seems more parsimonious not to.

There is no practical reason to refer to "mental percepts" at all, or for that matter — Richard B

Yes there is; to make sense of dreams, hallucinations, synesthesia, variations in colour perception (e.g. the colours of the dress are white and gold to some and black and blue for others), and visual cortical prostheses.

And these mental percepts exist in ordinary waking experiences to. They are what we ordinarily refer to when we use colour nouns, knowingly or not. An object reflecting various wavelengths of light is just the ordinary cause, nothing more.

But we do not teach what the meaning of "hallucinations" and "dreams" are by pointing out "mental percepts", but by teaching these words to someone who reports events that are not the case in particular circumstances.

Yet another reason to not to posit them.

I should be the one to apologize, I just meant to add some rhetorical flourish, not impune anything. — Count Timothy von Icarus

:smile: :up:

Funny enough, I've been working on a novel that involves people stuck in an infinite house. — Count Timothy von Icarus

Does the infinite house symbolize something? I never see all of the second house in my dreams.

Rather I would frame it like this: "our experiences don't always correlate with the enviornment the way we think they do under 'normal' conditions." — Count Timothy von Icarus

I agree with that.

However, we can certainly extrapolate from biology and neuroscience that a Boltzmann brain would need to exist in some range of ambient temperature, atmosphere, etc. in order to produce anything like say "5 seconds of human experience." — Count Timothy von Icarus

You're saying it seems reasonable to us that it would need the kind of environment we have. We can't really go further than that. We don't know exactly what's required for the existence of experience because we don't understand how it happens in the first place.

So you're denying the existence of dreams, hallucinations, synaesthesia, variations in colour perception, and basically the entire neuroscience of perception.

Well, you're welcome to, but you're wrong.

Well, I would say that the stick that looks bent is not, just pull it out of the water. And the same with dreams/hallucinations, what appears to have happen has not. Additionally, when a colorimeter instrument gets a color wrong, I don't posit that it is hallucinating the wrong mental percepts, I would fix it to ensure it detects the right colors.

At room temperature, a black body absorbs all frequencies of incident light, and a white body none, reflecting all of it if it is opaque.
Around 1000 and 9000 Kelvin, that same previously black body emits all frequencies of light, looking white — the Sun is a non-ideal black body. I am not sure what would happen to the previously white body; if it is an ideal white body, it shouldn't emit radiation at higher temperatures, like it doesn't at room temperature, so it should look white like before, but if the higher temperature affects reflectivity sufficiently, it could change colour.
https://e-learning.gunt.de/WL420/html/en_Basic%20knowledge%20on%20heat%20transfer/0000000042.htm

Since all perceptions are subjective responses, you can't claim any property to exist objectively, except to just say the perceptions must be being elicited by something. — Hanover

Isn't it just that there are objects of knowledge and there are the means by which we know these objects? The chair is an object of knowledge, and vision (and color) are the means by which we know this object. A mosquito is an object of knowledge, and pain is a means by which we know this object. The object impresses itself upon us via some faculty we possess.

Then in knowing the means we can also objectify it. Thus we can have knowledge of vision, or color, or pain, and this knowledge is obtained by some subtler means.

Elaborating, we can understand that a red chair exists via our visual perception of the color red, but then when we go further and consider "red" in itself we arrive at ambiguities. Does 'red' mean an experience, or a wavelength, or something else? If we consider redness as a wavelength then it is an object of knowledge that will have causal effects on even those substances which are not conscious. If we consider redness as the experience of a conscious subject then obviously it will not. Of course it is in fact both, and at each successive stage of inflection upon the means of knowing this duality will emerge. QM shows that even our knowledge is not merely "mental."

I haven't really been following this thread, but presumably at the bottom of Michael's claims is the idea that there are some objects of knowledge that are only accessible to certain types of knowers (e.g. knowers that possess taste and a certain type of taste bud can know that lemons are sour). Drawing a hard mental/non-mental line is almost certainly not possible or productive.

So, yes, apparently brains can generate experiences in the vacuum of space. All that is required is the appropriate neural activity, regardless of what causes and maintains it. — Michael

When one has an experience, it is an experience of something. When there is no "something", it's an hallucination.

But also, that "brains can generate experiences in the vacuum of space" is a presumption, not a conclusion, of the Boltzmann brain fancy.

And finally,

Supose you are a quantum fluctuation, having just popped into existence last Tuesday. The chances of you persisting into the next few seconds are vanishingly small. Chances are the world around you is ephemeral, and will disappear, or at the least not continue in a coherent fashion.

And yet for us, the world continues on in a regular and predictable fashion.

...that the world persists shows that it is very unlikely that you are a Boltzmann brain. — Banno

Six months later, Michale is still here to argue that he is most probably a Boltzmann brain, making it vanishingly unlikely that he is correct.

As a rule of thumb, if you are using physics to explain what red is, you've missed the point.

Children learn how to use the word long before they learn about atoms and frequencies.

And they use the word consistently and coherently to talk about things in the world around them. Again, how could we have agreement as to which things are red and which are not if being red were nothing more than an artifice of one's mind. That we overwhelmingly agree as to which things are red is shown by the continued use of the word. That we agree is explained by there being things in the world that we agree are red.

So red is not purely in one's mind, but also in our shared world.

Claiming red is like pain is a blunder. One does not see pain in boxes and cars and sunsets. The grammar of pain differs from that of colour

Nor does it make sense to claim red is an illusion. Colour persists and is shared.

None of which is to deny the physics of colour. The scientistic view that "there is no colour in the world" is inept, failing to recognise that humans create and maintain a shared world of language and belief.

The physics is irrelevant so long as when you ask for a red pen, that is what you are given.

n the case of colour there is no such thing as veridical. — Michael

That's plainly false. Red paint really reflects wavelengths of 700 nm, and to experience it as red is to have a veridical experience of it (unlike experiencing 700 nm as gray (if colorblind) or as any colour, sound, smell etc. (if hallucinating).

We can use colour terms however we like, but when we ordinarily use them we are referring to colour percepts, not an object’s disposition to reflect a certain wavelength of light. — Michael

That's also false, because the use of language is conventional, and evidently we refer to different things: you to an alleged "percept" inside the head, and I to the disposition of pigments and light. Most speakers use colour terms pragmatically or ostensively without commitment to philosophical subjectivism or dispositionalism etc.

..I look at the photo of the dress and describe its colours as white and gold.... ..someone else looks at that same photo and describes its colours as black and blue... — Michael

The colours in the photograph are susceptible to blend and interfere with changing light conditions on different screens and environments where the photo is displayed. Basically we don't just see the colours of the dress, but a blend of its colours with the colours from different environments or screens, and that's why different observers tend to see different colours.