This was written in a more innocent time.  Author has New Age spirit seeking endeavors as the primary threat to reason in current period!  Ironically he mentions psychologists who have not stood up to scrutiny.   Author also jumped the gun on his assessment of Neanderthals.  Book would have held up better if he had left out all characterization of Neanderthals and toned down his science of neurobiology.  He does not seem to be familiar with the works of Aristotle and so on to Dante -- each illustrated before Shakespeare the individual will.   Also why keep saying Socrates and the cave and not give credit and context to Plato?  That name swapping shows some disingenuous shaping from the beginning.   Otherwise, the ambition of the book made this a fun read.