For, "cats are a type of sailboat" could no doubt be defined as an "analytical truth," by fiat and entered into a database, but this would not make it true that cats are a type of sailboat. — Count Timothy von Icarus

Cats are my favorite kind of sailboat, because they are fast.

Perhaps Kant can help us? Or phenomenology? What methodology do you think you have access to that can answer the above and determine what direction this enquiry should take? Or do you think straightforward empiricism can resolve this matter? — Tom Storm

I don't think our science is so incomplete that we can't determine that there are regularities in nature independent of our cognitive faculties. For example, I routinely capture highly regular sequences of events using an oscilloscope, where the time intervals between events are measured in microseconds or nanoseconds. I have no reason to think that my cognitive faculties are capable of distinguishing events at such temporal resolutions, let alone impose such regularity on the events.

I don't see any sensible of interpreting such high speed events as products of my mind.

However, if we're going to amend these accounts of words to incorporate useful delineations, then we 'perceive' directly the representations which we are 'seeing' indirectly, — AmadeusD

I would think the representation is some collection of neurons in our brains firing with some relationship to a brainwave phase. However, I don't think it makes sense to say that "I see such a representation." At best I only vaguely imagine such a representation.

If the Direct Realist suggests that the dot "is" Mars, this reintroduces the problem of identity, in that how can a 1mm diameter dot in a person's visual field "be" a 6,794km diameter planet? — RussellA

Saying "I see Mars" is in effect saying that the photons which cause me to recognize that I am seeing Mars were reflected by Mars.

I'm afraid that it is rather mystifying to me, that someone capable of using the Internet, doesn't understand why an object the size of Mars at the distance of Mars would have the visual appearance that it does.

But should laws not refer to something? Law itself being nature sounds, for me at least, a bit inconceivable. — Pez

Is it inconceivable that there are naturally occurring negatively charged particles called electrons and positively charged particles caller protons that are naturally attracted to each other? Or is it more conceivable that electrons and protons don't actually have such properties, and are just following laws?

Quantum physicist Karen Barad has produced a model
of interaffecting matter that was inspired by the double
slit experiments.

Phenomena are ontologically primitive relations—relations without pre-existing relata... — Joshs

Does Barad claim a scientific justification for the claim?

Under your criterial demand the only "direct link" would be if the object was the experience. If the object is separate from the experience of it, then you would presumably say there is a gulf between them, and that this gulf justifies saying we do not experience objects directly. As others point out it all comes down to what is meant by "direct". I have long thought that experience can be thought about as direct or indirect, depending on the definitions and framing. So, the whole argument is undecidable in any absolute sense and is thus really a non-starter, another confusing artefact of thinking dualistically. — Janus

Very well said.

Non-Magical Intuition :
Intuition is a form of knowledge that appears in consciousness without obvious deliberation. It is not magical but rather a faculty in which hunches are generated by the unconscious mind rapidly sifting through past experience and cumulative knowledge.
https://www.psychologytoday.com/us/basics/intuition — Gnomon

Did you read the last paragraph?

It is possible to hone your powers of intuition. To some degree, intuition stems from expertise, which relies on tacit knowledge. Strengthening intuition requires making use of feedback, comparing the real-life outcomes of situations with the intuitive decisions you made. Even so, being highly intuitive in one domain of experience doesn’t guarantee reliability in every area.

:up:

:up:

Can there be a notion of progress in ethical or scientific understanding that doesnt need to rely on a true-false binary? — Joshs

In the case of scientific understanding, a spectrum from naive to well informed to me seems more relevant than a true false binary.

Can we make progress in understanding and navigating the world by continually revising this scheme, without having to declare the earlier versions ‘false’? — Joshs

Along the same lines, declaring the earlier versions naive seems more descriptive of the situation than false.

Yup. From what we have seen of quantum fluctuations, we know that's a possibility, given enough time? — Patterner

I'm not sure how we could say we know that.

I'm then questioning his suggestion that we can dismiss the conclusion that we are most likely Boltzmann brains a priori, as that then entails that we can dismiss some empirically well-supported scientific model a priori. For example, as per RogueAI's comment above, one supposed solution is to dismiss (4) a priori. Is that really rational? — Michael

First off, I don't know what you might be referring to with "really rational". As members of a social primate species go, (a social primate species which only began to develop literacy ~5500 years ago) I'd say Carroll is one of the more rational ones.

You see, there is empirical evidence we can intersubjectively consider, for a wide variety of scientific matters outside of physics. Carroll is certainly not ignorant of sciences outside of physics. It seems likely Carroll is inclined to consider The Big Picture.

It looks like you two are talking about the same thing. How many virtual particles have been observed in the same place at the same time? Because quantum fluctuations need to account for something like 1.4 x 10^26 atoms (I don't know how many particles that is) coming into existence all at the same time in the space that takes up a brain in order to make a Boltzman Brain. Not just that number, of course, but also the variety. — Patterner

:up:

And not just the number and variety but also the complexity of the arrangement.

As in, "wouldn't it be nice if we could avoid that circularity?" — Count Timothy von Icarus

Consider the degree to which people interact with the the world, including each other, avoiding circularity seems rather unrealistic. Just try to comprehend the feedback loops involved in the interactions of two good friends over a period of years, and perhaps the naivete of avoiding circularity will be obvious.

For me, as an electrical engineer, dealing with loopy causality is routine. So I can understand this not being so obvious to others. However to me the OP issues seem more a matter of trying to fit the complexity of the situation into an overly simplistic box.

Perhaps that's why I don't see the problems that you see. The problems you point out are where supervenience fails to explain something, or fails to rule out things that would be *bad* explanations. I don't see that as a problem, because I have much smaller ambitions for what supervenience is supposed to be. — flannel jesus

:up:

It’s tantamount to sorcery. — NOS4A2

I personally think, that in your specific case, it may be best to leave you thinking so.

This also seems to rely on disembodied cognition as a logical possibility. Logical possibility alone does not warrant belief/assent. — creativesoul

Boltzmann brains don't involve disembodied cognition. Cognition embodied much differently than ours for the most part, but not disembodied.

So, it seems to be exactly what I said above. The best evidence supports (1)-(4), and (7) follows. And his argument is that because (7) is just silly, we must reject (1), (2), (3), and/or (4) despite the evidence in their favour. It's a conceded dogma. — Michael

Did you read the full paper? If so, do you think that you followed Carroll's reasoning well?

I'm asking if that's rational. — Michael

It would be a straw man to claim that your argument and psychologizing stand in for Carroll's perspective.

Conclusion
We therefore conclude that the right strategy is to reject cosmological models that would be
dominated by Boltzmann Brains (or at least Boltzmann Observers among those who have
data just like ours), not because we have empirical evidence against them, but because they
are cognitively unstable and therefore self-undermining and unworthy of serious consideration. If we construct a model such as ΛCDM or a particular instantiation of the inflationary multiverse that seems to lead us into such a situation, our job as cosmologists is to modify it until this problem is solved, or search for a better theory. This is very useful guidance when it comes to the difficult task of building theories that describe the universe as a whole.
Fortunately, the criterion that random fluctuations dominate the fraction of observers in
a given cosmological model might not be as difficult to evade as might be naively expected, if Hilbert space is infinite-dimensional and local de Sitter phases settle into a truly stationary
vacuum state, free of dynamical Boltzmann fluctuations. That conclusion depends sensitively on how one interprets what happens inside the quantum state, an issue that is unfortunately murky in the current state of the art. If any were needed, this gives further impetus to the difficult task of reconciling the foundations of quantum mechanics and cosmology. [Emphasis added.]

Is there something that you disagree with in Carroll's conclusion?

Nah, it's a matter of my understanding of the strength of the evidence.
— wonderer1

So you're a cosmologist who understands the sigma level of each of (1), (2), (3), and (4)? I wasn't aware. — Michael

No, but just think about it. To have strong empirical evidence of BBs fluctuating into existence would require gathering evidence from the future, and lots of it. I'm fairly confident that physicists aren't doing so. This is a matter of modeling based on theories which have important matters unresolved, not a matter of observations of the proposed processes (BBs) occuring.

Do you think you might have a naive faith in the reliability of modelling based on incomplete scientific understanding?

You're dismissing some outcome on purely theoretical grounds irrespective of the strength of its evidence. — Michael

Nah, it's a matter of my understanding of the strength of the evidence.

You're claiming that the "absurdity" of (7) is sufficient justification to reject the evidence that suggests that (1), (2), (3), and/or (4) is true. — Michael

No. I am claiming 1-4 are insufficiently justified given the present state of scientific knowledge and my ability to distinguish well evidenced science from highly speculative science.

My view is along the lines of Sean Carroll's. (Again, from The Big Picture.)

It makes sense, as Wittgenstein would say, to apportion the overwhelming majority of our credence to the possibility that the world we see is real, and functions pretty much as we see it. Naturally, we are always willing to update our beliefs in the face of new evidence. If there comes a clear night, when the stars in the sky rearrange themselves to say, “I AM YOUR PROGRAMMER. HOW DO YOU LIKE YOUR SIMULATION SO FAR?” we can shift our credences appropriately.

The argument here provides a more precise account: either (7) is true or at least one of (1)-(4) is false. — Michael

Whether (1) is true is unknown. As far as I know, the universe as we know it might end with a false vacuum decay tomorrow.

It's hasn't been clear to me that when you say, "or our science is incorrect", that you recognize the relativity of incorrectness.

Which is why, as I said earlier, either we are most likely Boltzmann brains or our science is incorrect. — Michael

Are you familiar with The Relativity of Wrong?

How so? There will be Boltzmann brains that have the same observations as ordinary observers; and in fact, there will be significantly (infinitely?) more Boltzmann brains that have those same observations as ordinary observers. — Michael

Okay, show your math.

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.