Abstract

What I call the Similarity Principle says that a word ought to denote a class of things that are more similar to each other than to other things. A closely related formulation, which I’ll here take to be equivalent, is that a word ought to denote a class of things having something in common with each other that they don’t have in common with other things. The Similarity Principle is an example of an intuitively rational constraint on the lexicon of a language. If we imagine such strange words as “gricular” or “carple”, we feel intuitively that there would be something absurd about having such words in our language, and one explanation of this—indeed the explanation that is likely first to come to a person’s mind in some rudimentary form—is that these words violate the Similarity Principle.