The task must be made difficult, for only the difficult inspires the noble-hearted.

逻辑学研究不仅仅是关于形式系统，更是关于理性思维和话语的规范。

Prediction is very difficult, especially about the future.

一言一行，效法古代圣贤，就会道德长进；功名利禄，听任天命安排，就会心意闲适；因果报应，考虑子孙福祸，就会办事公正；口体之事，考虑疾病袭来，就会俭朴节省。