As a researcher in these fields: this reasoning is tired, overblown, and just wrong. We have a lot of understanding of how the brain works overall. You don't. Go read the active inference book by Friston et. al. for some of the epistemological and behavioral mechanics (Yes, this applies to llms as well, they easily satisfy the requirements to be considered the mathematical object described as a markov blanket).

And, yes, if you could somehow freeze a human's current physical configuration at some time, you would absolutely, in principle, given what we know about the universe, be able to concretely map input to into actions. You cannot separate a human's representative configuration from their environment in this way, so, behavior appears much more non-deterministic.

Another paper by Friston et al (Path Integrals, particular kinds, and strange things) describes systems much like modern modeling and absolutely falls under the same action minimization requirements for the math to work given the kinds of data acquisition, loss functions, and training/post-training we're doing as a research society with these models.

I also recommend https://arxiv.org/abs/2112.04035, but, in short, transformer models have functions and emergent structures provably similar both empirically and mathematically to how we abstract and consider things. Along with https://arxiv.org/pdf/1912.10077, these 4 sources, alone, together strongly rebuke any idea that they are somehow not capable of learning to act like and think like us, though there's many more.