My largest problem with this post comes right at the beginning:

humans are not utility maximizers and often refuse to give precise numerical probabilities. Nevertheless, their actions reflect a "hidden" probability.

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although a mind "hosts" a probability estimate, that mind does not arbitrarily determine the estimate, but rather calculates it according to mathematical laws from available evidence.

If our basic brain processes are irrational, there is no reason why there has to be a well-defined probability in there somewhere. You might extract a probability by some method or another, but you might also extract method-dependent gobbledygook.