Adaptation is the mind's greatest achievement.
When you solve a mathematical problem, you don't just get the answer - you understand why it's the answer.
The knowledge of the circumstances of which we must make use never exists in concentrated or integrated form, but solely as the dispersed bits of incomplete and frequently contradictory knowledge which all the separate individuals possess.
食欲,对食物的渴望,是胃腺持续而强大的刺激物。