E.O. Wilson in Consilience: The Unity of Knowledge

Without the stimulus and guidance of emotion, rational thought slows and disintegrates.  The rational mind does not float above the irrational; it cannot free itself to engage in pure reason.  There are pure theorems in mathematics but no pure thoughts that discover them.  In the brain-in-the-vat fantasy of neurobiological theory and science fiction, the organ in its nutrient bath has been detached from the impediments of the body and liberated to explore the inner universe of the mind.  But that is not what would ensue in reality.  All the evidence from the brain sciences points in the opposite direction, to a waiting coffin-bound hell of the wakened dead, where the remembered and imagined world decays until chaos mercifully grants oblivion.