The soul is that which denies the body. For example, that which refuses to run when the body trembles, to strike when the body is angry, to drink when the body is thirsty.
If I were required to guess off-hand, and without collusion with higher minds, what is the bottom cause of the amazing material and intellectual advancement of the last fifty years, I should guess that it was the modern-born and previously non-existent disposition on the part of men to believe that a new idea can have value.