I think one of the biggest mistakes we have made as an industry is conflating the words “AI” and “LLMs.” The irony is right there on the surface. Naming is one of the hardest things to do in software, and we’ve done it poorly for the primary tool of software.


Thank you for the Carroll paper. I’m actually looking for stuff like that atm.
In the paper, he caveats
so I’m very unclear how this paper can present a hard anti-materialist barrier, when he makes it clear that the paper presumes physicalism. I’ve only read half of it so far, will continue …
Well, the burden of proof doesn’t lie with Carroll. Instead, the entire point is that the non-materialist has the burden of evidence:
Otherwise I can rely upon Newton’s flaming laser sword; every time you ask about the possibility of non-materialism, I can ask you for the corresponding experiment which opens that possibility. Note that sometimes this is scientifically fruitful, as in the discovery of infrasound leading to many debunkings of hauntings as well as unlocking the secrets of elephant communication. (The more radical position of anti-materialism was conclusively refuted during the colonial era, so we cannot assume that the material world is only hypothetical.)
This is all made stark in Figure 4, p15, which shows that any possible physical force not in the Standard Model would be so weak and subtle as to be undetectable by humans; when a human claims that they are sensitive to such a force, they have incorrectly implicitly assumed that their body is physically capable of interacting with such a force in a perceptible way. The argument goes much like the argument against electrosensitivity: if you really could sense the weak experimental force then you would be constantly sensing the much stronger ambient forces from the outside environment which we can’t mute.
A common retort is that quantum states are merely our epistemic knowledge as humans about a fundamentally-unknowable micro-reality below our scale of perception. However, the PBR theorem rules that out by insisting that the quantum wavefunction is ontic. Leifer spent about two years struggling against this result in vain and eventually published Leifer 2014, which both serves as a great overview of the no-go theorems in ontological models and also as an example of how difficult it can be to unlearn previously-accepted beliefs.
The PBR theorem assumes preparation independence which is a local assumption.
Very interesting. Anywhere I can read more on that? Or is it standard knowledge in QM foundations?
The PBR theorem argues that if the quantum state is purely epistemic, then different preparation procedures can correspond to overlapping probability distributions over underlying states, which creates ambiguity about which preparation was used based only on observed statistics. In contrast, if the quantum state is ontic, distinct quantum states correspond to non-overlapping distributions, so in principle one can always infer the preparation given sufficient data. The theorem shows that any model with such overlap cannot reproduce all quantum predictions, and therefore concludes that the quantum state must be ontic.
However, this conclusion relies on the assumption of preparation independence, meaning that independently prepared systems have independent underlying states. If this assumption is relaxed and underlying states can depend on the joint preparation context, then overlap need not occur even in models that are otherwise epistemic. See this paper for example: https://arxiv.org/pdf/1811.01107. In this sense, such models may still be called psi-ontic under PBR’s definition, since distinct wavefunctions correspond to distinct underlying states, but the distinction reflects differences in preparation conditions rather than the existence of distinct physical wave-like entities.
Related work has pointed out that PBR’s criterion can classify intuitively epistemic models as ontic when preparation independence is violated, as discussed in this paper: https://arxiv.org/pdf/2109.02676v2. Other results show more explicitly that by dropping this assumption, one can construct models consistent with quantum mechanics in which different quantum states correspond to the same underlying reality, allowing genuine overlap, as in this paper: https://arxiv.org/pdf/1201.6554.
You should check out this lecture: https://pirsa.org/12050021
Thanks! I’ve bookmarked those, and will watch the lecture.
Sibling comment is great for PBR. For KS, unfortunately most schools have a blind spot around it. This is partially because KS directly implies the legendary Bell’s theorem, which is experimentally testable and has allowed folks to prolong their grief over objective reality by bargaining with those experiments rather than doing maths; teaching Bell’s theorem is less of a headache while still breaking classical assumptions. It’s also partially because KS is not well-understood as a matter of folklore. I would say that maybe nLab’s page on KS states the important part, but they still hedge by using lots of formal language. Here’s an informal consequence of KS:
Given. We exist in three spatial dimensions.
Given. Photons of the Standard Model have spin 1.
Corollary (QM is indefinite). The spin of a photon isn’t definite prior to measurement.
This leads to the infamous Kochen-Conway theorem, better known as the “free will” theorem: if humans have free will then photons have free will. Kochen has been insistent that this family of results is solid and wants his peers to pay attention; he releases a position paper every few years on the topic, e.g. Kochen 2017 or Kochen 2022.
How does the burden lie with the reader, rather than the author who has explicitly stated they are assuming physicalism. Why must we assume physicalism?
You’re welcome to ask, but not all truths are experimentally verifiable. I read Newton’s flaming laser sword to mean that only science or logic can reveal truths, which isn’t at all the case.
I’ve enjoyed discussing this with you - you’ve been clear, and added some interesting references. I’m not sure this medium really lends itself to in-depth discussion. I think we both need more space to understand where the other is coming from, and I don’t see us progressing in that direction.
By the way, I really hope that you consider synthesizing concepts. As an exercise, Carroll concludes from his premises that:
But consider the following quote from Strange Loop at the end of Chapter 18, “The Blurry Glow of Human Identity”. Remember, Hofstadter is a physicist, arguably as influential as Carroll in quantum theory, and no less of an anti-dualist or materialist. So, as an exercise, synthesize for yourself an understanding of why Hofstadter says:
By synthesizing concepts, do you mean combining them? I hope you’re not suggesting what that sounds like.
I will return to Carroll’s paper, but I still don’t see how it can prove anything, due to the paragraph I quoted.