The desires， and other passions of man， in themselves， are in his own power； his real difficulties are， to know when they are to be controlled， and when not.

心理学必须是一门功能的科学，而不仅仅是事实的科学。

出自北齐·颜之推《颜氏家训·勉学》。博士：指学识渊博的人。一个学识渊博的人打算去买一头驴，可是写了三页纸也没有见到一个“驴”字。这句话常用来讽刺文章文辞繁冗、不得要领、苍白空洞。

He who wants to do good knocks at the gate； he who loves finds the gate open。