That's a very difficult question to answer. It's an open problem in academia.

To tease out something often it can be useful to approach problems from the opposite end. For example what is NOT the way in which human cognition works?

We know how LLM's function, humans certainly do not function in a similar fashion. For one I can reason well enough that next year is 2026 without having most all human literary output fed to me. It's amazing how much the human mind does with so little information.