Abstract

The article argues that Aristotle’s Square of Opposition is introduced within a context in which there are other squares of opposition. My claim is that all of them are interesting and related to the traditional Square of Opposition. The paper focuses on explaining this textual situation and its philosophical meaning. Apart from the traditional Square of Opposition, there are three squares of opposition that are interesting to follow: the square of opposition with privative terms (19b19-24), the one with indefinite-term oppositions (20a20-23), and the modal square (22a24-31), which are all contained in Aristotle’s De Interpretatione 10 and 13. The paper explains that all these squares follow a common plan, which is to demonstrate that every armation has its own negation, whatever is the proposition either categorical or conditional, or modal or non-modal, which is a reference to the universal importance of contradiction in logic.