What can be said at all can be said clearly, and what we cannot talk about we must pass over in silence.
一切能被说出的都能够清楚地被说出，而我们不能谈论的，必须保持沉默。
逻辑学研究不仅仅是关于形式系统，更是关于人类推理的本质。
释义：知足常乐的人会感到快乐，没有欲望没有追求的人会感到轻松。
A theory should not attempt to explain all the facts, because some of the facts are wrong.