微信公众号“数理逻辑与哲学逻辑”。

规范逻辑有两个模态算子。

将在后续文章中详细讨论，其所用时间为t。

(By “paradox” one usually means a statement claiming something which goes beyond (or even against)‘common opinion’ (what is usually believed or held). Paradoxes form a natural object of philosophical investigation ever since the origins of rational thought; they have been invented as part of complex arguments and as tools for refuting philosophical theses.)”