And again, again, it remains that there are no tight grounds for accepting the calculations involved. It is "cognitively unstable" - or if folk prefer simple language, there are no observations that settle the issue, and hence it remains mere speculation. — Banno

Exactly.

You think a quantum fluctuation universe is more likely than quantum fluctuation brains with false memories? — Michael

As an explanation for our observations, yes.

Adding to the above, there's also Is the Universe a Vacuum Fluctuation?: — Michael

That is not nearly as self defeating as a scientific hypothesis.

What is clear is that the physics is incomplete. Hence there remains good reason for Boltzmann scepticism. — Banno

:up:

"The consensus amongst cosmologists is that some yet to be revealed error is hinted at by the surprising calculation that Boltzmann brains should vastly outnumber normal human brains."

They accept that the science entails that we are most likely Boltzmann brains. They consider this proof that something is wrong with the science. — Michael

What you put in quotes there was something that someone wrote on Wikipedia. Can you quote a physicist making such a claim?

Several are mentioned in the Wikipedia article, e.g. Boltzmann, Eddington, Feynman, Sean Carroll, and Brian Greene. — Michael

Those are people who have considered the possibility that we are Boltzmann brains. Not people who claim what you attribute to them. I already quoted Sean Carroll on the topic and it seemed pretty clear to me that Carroll doesn't make the claim that you are attributing to him. Do you agree?

Which is why I asked the question: given that we have scientific evidence that entails that we are most likely Boltzmann brains, what justifies our claim that we are not most likely Boltzmann brains? — Michael

What scientist makes the claim that we have scientific evidence that we are most likely Boltzmann brains?

So it's back to what I said here. Either we are most likely Boltzmann brains or we cannot trust our scientific knowledge. — Michael

That's a false dichotomy, and things aren't nearly that black or white.

There are areas in which I can and do trust my scientific knowledge with my life (and the lives of other people) depending on it. There are other areas of scientific knowledge in which I can't trust my knowledge to nearly the same extent.

Perhaps the most relevant question in this discussion is the extent to which you can trust your scientific knowledge?

FWIW:

ChatGPT 3.5

User
are there any physicists who believe we are boltzmann brains

ChatGPT
The concept of Boltzmann brains is a speculative idea in physics proposed by Ludwig Boltzmann and later expanded upon by physicists like Sean Carroll and others. It suggests that it's statistically more likely for a conscious observer, like a human brain, to spontaneously fluctuate into existence in a high-entropy state rather than to arise through the natural process of evolution. While some physicists entertain this idea as a thought experiment to explore the implications of cosmology and the second law of thermodynamics, it's not widely accepted as a serious hypothesis. Instead, it raises questions about the nature of reality and our understanding of the universe.

User
do any physists claim to be a boltzmann brain

ChatGPT
It's unlikely that any physicist would claim to be a Boltzmann brain in a literal sense. The concept of Boltzmann brains is primarily a thought experiment rather than a literal assertion about the nature of consciousness or existence. Physicists who discuss the idea typically use it to explore the implications of certain cosmological theories and the second law of thermodynamics, rather than as a statement about their own existence.

Why? They're entailed by our best scientific theories. — Michael

They are entailed by extrapolation of some scientific theories to a future universe we don't find ourselves in a position to observe. There are lots of theories outside of physics that have a lot of evidentiary support as well.

To quote Sean Carroll from The Big Picture:

Is it possible that you and your surrounding environment, including all of your purported knowledge of the past and the outside world, randomly fluctuated into existence out of a chaotic soup of particles? Sure, it’s possible. But you should never attach very high credence to the possibility. Such a scenario is cognitively unstable, in the words of David Albert. You use your hard-won scientific knowledge to put together a picture of the world, and you realize that in that picture, it is overwhelmingly likely that you have just randomly fluctuated into existence. But in that case, your hard-won scientific knowledge just randomly fluctuated into existence as well; you have no reason to actually think that it represents an accurate view of reality. It is impossible for a scenario like this to be true and at the same time for us to have good reasons to believe in it. The best response is to assign it a very low credence and move on with our lives.

The general gist seems to be:

1. our scientific theories suggest that we are most likely Boltzmann brains
2. we are not most likely Boltzmann brains
3. therefore, our scientific theories are mistaken

The point I am making is that, by this very argument, (2) is not supported by the scientific evidence. Rather it's something like "common sense" or "intuition" or "faith". — Michael

I've been pointing out that there is science outside of physics, and on the basis of sufficient knowledge of the diversity of scientific findings we have reasons to reject 1.

I'm then asking if it's reasonable to favour common sense, intuition, or faith over scientific evidence. — Michael

I'd say it is human nature for us to favor intuition regardless of whether it is reasonable to do so. Regardless, I've pointed out that there are multiple lines of scientific evidence to consider, and one speculative extrapolation in physics doesn't provide a basis for dismissing the larger scientific picture that allows for the existence of this forum.

Of course, if you admit that we can sometimes be justified in believing that the scientific evidence is mistaken then you open yourself up to arguments for idealism or theism, as it would certainly be hypocritical, or special pleading, to argue that we must believe in an external material world because there is scientific evidence for it but that we must not believe that we are Boltzmann brains even though there is scientific evidence for it. — Michael

I'm a fallibilist and I haven't argued that "we must believe" anything.

:up:

This isn't just an assumption. Rather:
— Michael

The preponderance of evidence to date, based on measurements of the rate of expansion and the mass density, favors a universe that will continue to expand indefinitely, resulting in the "Big Freeze" scenario below...

BB speculations are scientifically self defeating.

We only take such evidence seriously on the assumption that humans actually make empirical observations rather than experience phantasms occuring in a BB. Given the bigger picture, resulting from empirical observations considered more broadly, the evidence points towards us being the result of biological evolution. Do you think the majority of physicists would disagree?

You're right that it's not a matter of observation (and perhaps that my binary distinction is unfair), but it's wrong to suggest that it's as simple as speculation. Rather it's a consequence of our best understandings of quantum mechanics and thermodynamics. — Michael

I'm not suggesting it is simple speculation, but it does depend on assumptions such as that the universe is eternal. Furthermore, science is hardly exhaustively covered by quantum mechanics and thermodynamics, and the best scientific case is for us being the result of biological evolution.

There are, broadly speaking, four possibilities:

1. We are Boltzmann brains and our scientific theories are mostly correct
2. We are Boltzmann brains and our scientific theories are mostly incorrect
3. We are not Boltzmann brains and our scientific theories are mostly correct
4. We are not Boltzmann brains and our scientific theories are mostly incorrect

If our scientific theories are mostly correct then either (1) or (3) is the case, with (1) being most likely (as per those very scientific theories).

So one of these is true:

a. We are most likely Boltzmann brains (1 or 3)
b. Our scientific theories are mostly incorrect (2 or 4) — Michael

This ignores the fact that some aspects of science are far more speculative than others, and that a binary distinction between mostly correct and mostly incorrect doesn't address the fact that Boltzmann brains are a matter of speculation and not observation.

It doesn't follow that I am most likely not a Boltzmann brain. It only follows that the probability that I am a Boltzmann brain gets smaller as the time increases. But due to the sheer number of Boltzmann brains, it is always the case that the probability that I am a Boltzmann brain is greater than the probability that I am not a Boltzmann brain. — Michael

It seems to me there is a problem with you being a Boltzmann brain and yet so predictable. Should we expect that if you are a BB? Where's the batty?

:100: :up:

In the context of Neuroscience this seems very poor curriculum. A historical perspective maybe? — Mark Nyquist

It's a philosophy course. Why think it is "in the context of neuroscience"?

How far along is your daughter in her study of neuroscience?

When we believe any thing of external existence, or suppose an object to exist a moment after it is no longer perceived, this belief is nothing but a sentiment
— David Hume

That quotation is from the “Abstract”, which is a summary of the Treatise. The argument itself is around 1.4.2 (that’s Book.Part.Section).

But there must be secondary sources that could make it more manageable. — Jamal

Bringing up the Hume quote is good, but can your daughter then make a case for it not being nothing but sentiment, but rather a matter of pattern recognition occurring in neural networks?

Perhaps the latter is the result of unreasonable expectations about the former. As if by asking a question there must then be an answer. The natural sense of awe and wonder is lost. Replaced by artifactual realms beyond and a desire for escape and transcendence. — Fooloso4

So it seems to me.

My experience off this forum has me tending toward thinking the poison is quite well contained here — AmadeusD

And yet here you argue that you don't know anything about the world around you. So I don't know why we should take you seriously when you talk about experience off the forum.

What is the light reflected/refracted by?
— wonderer1

No idea. My part in the process(and as such, the point at whcih I could say anything about it) comes after that, as best I can tell. I could say "the objects" but then im stuck with literally nothing else to say about it. — AmadeusD

Hopefully your philosophy poisoning isn't so deep that you can't recover.

Virtual particles pop out of a vacuum attached to a QM universe. Moreover, they have physical causes.
— ucarr

Have any of these mathematical conveniences ever been detected? — jgill

Casimir effect:

The typical example is of two uncharged conductive plates in a vacuum, placed a few nanometers apart. In a classical description, the lack of an external field means that there is no field between the plates, and no force would be measured between them.[13] When this field is instead studied using the quantum electrodynamic vacuum, it is seen that the plates do affect the virtual photons which constitute the field, and generate a net force[14] – either an attraction or a repulsion depending on the specific arrangement of the two plates. Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. This force has been measured and is a striking example of an effect captured formally by second quantization.[15][16]

Every explanation attempting to do so just ignores entirely that we literally do not see objects, but reflected/refracted light which in turn causes us to 'see' a visual construct. — AmadeusD

What is the light reflected/refracted by?

I thought that too, except "Sherlock Holmes" refers to something that seems to go beyond something that's just "instantiated in a brain". — RogueAI

Well, there are lots of ideas of ideas of Sherlock Holmes instantiated in lots of people's brains. But what seems to go beyond something instantiated in a brain?

I mean, when you're reading Arthur Conan Doyle or Mary Shelly or Stephen King, are you thinking of brains? — RogueAI

No. Things can be represented with other things, such as ideas with written words. Typically we are thinking of things represented in our brains. Representations in our brains no more need to to resemble what is represented, than a string of letters on a page needs to resemble the landscape it describes.

You're talking about fictional things: ghosts, Dracula, Sherlock Holmes, God, etc. Fictional things exist as ideas, otherwise, we wouldn't be able to intelligently talk about them. — RogueAI

From ny physicalist perspective you are equivocating between an idea as instantiated in a brain, and what the idea refers to.

I can always count on you to go for the ad hominem. A lot of materialists here do. It's like they're emotionally invested in it or something. — RogueAI

And it is like you don't recognize that your ignorance makes your opinion on the matter uninteresting, and tedious to respond to.

I'm a scientific ignoramus. — RogueAI

At least we can agree on that.

What theory of consciousness do you like? — RogueAI

It is too soon for anyone to be justified in calling something a scientific theory of consciousness.

However, speculation plays an important part in how scientific understanding develops.

So while in my opinion the IIT crew is being pretentious in calling IIT a theory, I wouldn't call it pseuoscience, so much as speculative hypothesizing that serves a useful role in science.

But you haven't responded to the issue of you making arguments from ignorance. Why do you consider yourself competent to judge what the state of science should be at present? Surely it is not a matter of you considering yourself scientifically well informed. Right?

If there was progress to be made explaining consciousness, science would have made it by now. — RogueAI

This just shows your ignorance of the technological challenges in the way of gaining detailed information about neurological processes. So it doesn't do anything to dispel my impression, that all you have is an argument from ignorance.

The one data point that I think defeats physicalism (or makes it very unlikely), is the fact that I'm conscious. Physicalism cannot explain that and probably never will. — RogueAI

Can you provide any reason to think that you aren't making an argument from ignorance?

Argument from ignorance (from Latin: argumentum ad ignorantiam), also known as appeal to ignorance (in which ignorance represents "a lack of contrary evidence"), is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false or a proposition is false because it has not yet been proven true. This represents a type of false dichotomy in that it excludes the possibility that there may have been an insufficient investigation to prove that the proposition is either true or false.[1] It also does not allow for the possibility that the answer is unknowable, only knowable in the future, or neither completely true nor completely false.[2] In debates, appealing to ignorance is sometimes an attempt to shift the burden of proof.

My pee pee is big enough to fit inside two women at the same time. — Brendan Golledge

But I don't bother about more refinement of definitions about physics versus chemistry — Ypan1944

Seems important to bother with, in serious consideration of emergence.

Yes, you are right, but the chemical features of "heavy water" are exactly the same as "normal" water. The features you mentioned are just physical, not chemical. These physical aspects are not emergent (they are the direct result of the fact that it is a heavier atomic nucleus). The chemical features are indeed emergent, depending on the specific electron configuration. — Ypan1944

No the chemical properties are not exactly the same. For example, the pH of heavy water is 7.44 instead of 7.0.

https://en.m.wikipedia.org/wiki/Heavy_water

For reactions between atoms or molecules, only the "outside" of an atom (i.e. the outermost electrons of the atom) plays a role. — Ypan1944

It seems that you were taught a simplistic version of chemistry.

Deuterium oxide, also known as “heavy water” or “deuterium water”, is the compound of oxygen and the heavy isotope of hydrogen, namely deuterium. It is called heavy water because its density is greater than H₂O and its chemical formula is D₂O. Deuterium contains a neutron and proton in its nucleus, which makes it twice as heavy as protium (hydrogen), which contains only one proton. Deuterium oxide is colorless and odorless liquid in normal temperature and pressure. Compared to ordinary water, its chemical characteristic is relatively inactive with specific gravity of 1.10775 (25 ℃), melting/freezing point of 3.82 ℃, and boiling point of 101.42 ℃. The hydrogen bond strength and degree of association between heavy water molecules are both stronger than that of ordinary water molecules...

https://www.isowater.com/what-is-deuterium-oxide-heavy-water/

The supposed "heat death" is an interesting issue. The heat death is the result of entropy which is the natural effect of the passage of time. "Entropy" refers to energy which is unavailable to the system, but cannot be shown to have escaped the system. So by the rules of the conservation law, that energy must still be within the system somehow, only not available to the system.

This leaves us with the question of, "what form could this energy have?". It is not "energy" as we know "energy", because "energy" is defined as the capacity to do work, and this energy is denied of that capacity. It is only "energy" because the law of conservation dictates that it must be conserved as "energy". — Metaphysician Undercover

Typically the form of energy, which shows up as entropic losses of a system, is in the form of heat. There is nothing all that mysterious about such heat energy. It simply becomes difficult to make any use of heat energy when all parts of a system are at nearly the same temperature.

Because you're not getting the distinction between an empirical theory and a metaphysical stance. — Wayfarer

I'm afraid that a lot of time spent in these sorts of dicussions has taught me to interpret statements like that as you sticking your fingers in your ears and saying, "La, la, la, I can't hear you!"

Isn't that enough? The fact that thought can have similar effects to practical physical enaction is meaningful to me. — Pantagruel

You had said there were "unique" features, so I was curious as to support for this uniqueness.

Brain scans of Buddhist monks exhibit a variety of unique features, including enhanced neuroplasticity. — Pantagruel

Can you provide a reference?

The article Buddha's Brain: Neuroplasticity and Meditation says, "When the framework of neuroplasticity is applied to meditation, we suggest that the mental training of meditation is fundamentally no different than other forms of skill acquisition that can induce plastic changes in the brain."

If someone claims to have mathematical knowledge it can be demonstrated. Can the same be said of someone who claims to have mystical knowledge? — Fooloso4

This touches on my interest in intuition, understood as deep learning in neural networks. It seems to me that there are two seperate issues involved.

1. Having demonstrable knowledge.
2. Having an explanation for that knowledge.

Though I haven't done any meaningful degree of study of the history of explanations for intuition, my impression is that intuition has been mysterious and subject to being explained in supernatural or mystical terms until the 1980s, when the beginnings of a neuroscientific basis for understanding intuition were developed.*

Given that intuition has been (and probably still is for most) such a mystery, it seems understandable to me that people often have practically demonstrable knowledge while often being mistaken in their beliefs as to the basis of that knowledge.

* The second wave blossomed in the late 1980s, following the 1987 book about Parallel Distributed Processing by James L. McClelland, David E. Rumelhart et al., which introduced a couple of improvements to the simple perceptron idea, such as intermediate processors (known as "hidden layers" now) alongside input and output units and used sigmoid activation function instead of the old 'all-or-nothing' function. Their work has, in turn, built upon that of John Hopfield, who was a key figure investigating the mathematical characteristics of sigmoid activation functions.[2] From the late 1980s to the mid-1990s, connectionism took on an almost revolutionary tone when Schneider,[4] Terence Horgan and Tienson posed the question of whether connectionism represented a fundamental shift in psychology and GOFAI.[2] Some advantages of the second wave connectionist approach included its applicability to a broad array of functions, structural approximation to biological neurons, low requirements for innate structure, and capacity for graceful degradation.[5] Some disadvantages of the second wave connectionist approach included the difficulty in deciphering how ANNs process information, or account for the compositionality of mental representations, and a resultant difficulty explaining phenomena at a higher level.[6]

The current (third) wave has been marked by advances in Deep Learning allowing for Large language models.[2] The success of deep learning networks in the past decade has greatly increased the popularity of this approach, but the complexity and scale of such networks has brought with them increased interpretability problems.[7]

https://en.m.wikipedia.org/wiki/Connectionism

Go there! It's more interesting than most stuff on here currently. — creativesoul

I was hoping you would start the thread. :wink:

I'm better at riffing off things others have said. It's not clear to me how I would start such an OP without it becoming much too long and meandering.

I'm moving this discussion back to this thread where it is more appropriate.

...But they insist nevertheless that at the end of the day such items are physical, or at least bear an important relation to (or supervene on) the physical.
-SEP

That is what I'm disputing. But it doesn't mean that I believe that evolution or the Big Bang didn't occur, or that the Universe is not as science describes it, or other empirical facts. There's no need for me to do that. — Wayfarer

Again, I brought up young earth creationism as an example of science denialism, not to say that you have the same view as a YEC. There are all sorts of science denialism, such as AGW denialism.

It seems that you are avoiding looking at, whether the following statement of yours is indicative of science denialism.

There is no scientific evidence for physicalism. — Wayfarer