Description: A basic question in philosophy is, ""how do we know what we think we know? Constructivists answer this question as follows: categories for constructing reality reside in the human mind, so reality cannot escape the mind's limitations. Human beings constantly assimilate new knowledge and experience. Constructivists apply the same logic to the question of truth. What we claim to be true is always provisional. New information and breakthroughs may supplant what we presently hold to be true. Ultimate or absolute truth is unknowable. In The Flipside of Godspeak, John Crosby applies...