here's the thing though, we aren't talking about an objective fact. Maybe humans don't exist at all, maybe we're boltzmann brains floating in a nebula. We're t

here's the thing though, we aren't talking about an objective fact. Maybe humans don't exist at all, maybe we're boltzmann brains floating in a nebula. We're talking about self reported probabilities humans are aware of. And yes, I am actually 100% sure of some facts about myself. (I have a sister, I live in an apartment). I am aware, abstractly, that such things may not be true in a sort of plato's cave shadows etc, but I will for all intents and purposes act and believe that they are certain. If such things were proven to not be true, I would be shocked to my very core; I am shocked because it broke a notion I had, if I was aware in my actual core of the possibility that it may not be true, I wouldn't be shocked. To survive, our biological machinery must make assumptions and round probabilities. To do otherwise would be to be paralysed with indecision. (what if there is some small chance an elaborate deathtrap has been sprung that will kill me if I move even slightly at this very moment? what about the next moment?)