The human brain is very poor at knowing things. On the other hand, it is very rich at believing things. What, for example, does your brain believe? I can tell you some of the things that my brain believes.
I believe (but cannot know) that I may well be the happiest man in the world. I believe that the world that I live in is la dolce vita!
Whatever may be objectively true in physics in the Milky Way, and beyond, as far as my brain is concerned (as far as the cognitive physics of my subjective neurosphere is concerned) my brain has created for me the good life!
We could just stop here. Or, we can go on …