Asking the brain to understand where reality comes from is like asking a robot to dismantle itself to find out what it's made of -- you won't have a machine after the dismantling is done, and therefore no answer.
Circa 250 B.C.:
Archimedes: Eureka! I have finally discovered the solution. EUREKA!!!
Cop: Everything all right over here sir?
Archimedes: Alright? I...
The vast majority of the knowledge humans have assembled over the centuries, has been lost. The world's geniuses either kept their revelations to them...