爱是对人类存在问题的唯一理智和令人满意的回答。
Love is the only sane and satisfactory answer to the problem of human existence.
每种心理状态都有其存在的目的;要理解它,我们必须询问它在更广泛的行为系统中发挥什么功能。
Prediction is very difficult, especially about the future.