Care to elaborate? Is it well established that brains do not work at any level probabilistically? I understand the mid-level abstraction is clearly different b

Care to elaborate? Is it well established that brains do not work at any level probabilistically? I understand the mid-level abstraction is clearly different between LLMs and brains. The whole made of meat vs wires, etc, to start with. But, honestly asking. I can't see how they can differ in a fundamental level in the specific regard of probability. Either both are probabilistic, be it explicitly in its construction or at a fundamental (quantum?) level, or deterministic again at either level, if we go with the mecanicist vibe. Am I missing something?