Abstract

This chapter focuses on one of the common fallacies in Western philosophy called 'affirming a disjunct' (AAD). It presents a few examples of fallacies in arguments caused by an ambiguity in the English word or. Because context makes the meaning clear in everyday usage, we might never have thought about this ambiguity before, but we actually use the word or in two very distinct ways. One type of or is known as “inclusive”, and the other type is known as “exclusive”. AAD occurs when someone mistakenly believes that an inclusive or is an exclusive or. Importantly, not every or statement can fall prey to AAD. The argument known as a disjunctive syllogism sets out two possibilities that are mutually exclusive. When someone is dead, she/he is not alive, and when someone is alive, she/he is not dead.