Abstract

This chapter focuses on one of the common fallacies in Western philosophy called 'undistributed middle'. “Distribution” is meant to describe the extension of the term, that is, how many things it applies to. Basically, demanding that the middle term be distributed in at least one of the premises ensures that there is going to be some overlap between the two premises so that it is possible to deduce their relation. If the middle term is undistributed, the argument is invalid. There exist any number of ways this fallacy could be avoided; that is, the way to avoid the fallacy of undistributed middle is to create any valid syllogism. While not all syllogisms with distributed middles are valid, a syllogism must have a distributed middle in order to be valid. Distribution of the middle term is thus a necessary but not sufficient condition for a valid syllogism.