>we've probably all heard the thing of harsher sentences being given in the hour before lunch

That suggests determinism though.

I mean I agree with you overall. Either humans decision making is a system so complex it appears non-deterministic, or it is deterministic. Practically speaking, we are non-deterministic.

Let's not conflate non-deterministic with inaccurate though. Non-deterministic systems can be 100% accurate. https://en.wikipedia.org/wiki/Las_Vegas_algorithm