Abstract:

All premises of an inference can be regarded as presuppositions of the inference. Inferences in daily life tend to be expressed in omitted forms, where some premises are not explicitly given. Accordingly, it is very important to analyze presuppositions in an all - round way. This paper also explores some rules of inference in classical logic and modal logic, and discusses the validity of these rules of inference in daily life.

Key words: presupposition, inference, rule of inference