【释义】令人快乐的事情有很多种类，不能固执地用同一种标准来讨论。

La poesía es la única prueba concreta de la existencia del hombre.

It is impossible to live without failing at something, unless you live so cautiously that you might as well not have lived at all.

行为由当前刺激情境和过去的强化历史决定。