A PROBLEM ABOUT THE IDEA OF FAMILY RESEMBLANCES
IN §65 of the Philosophical Investigations, in the course of introducing the idea of family resemblances, Wittgenstein writes:
Instead of producing something common to all that we call language, I am saying that these phenomena have no one thing in common which makes us use the same word for all, -- but that they are related to one another in many different ways. And it is because of this relationship, or these relationships, that we call them all 'language'.
Here both the words 'which make us use the same word for all', and the final sentence, suggest that Wittgenstein thought it is in virtue of various resemblances, of a kind he went on to describe further, that we call various things by the same name, or in other words, that we do or can use family resemblances as a criterion of class membership. Is this what he did intend? As I will explain later, it is in many ways an unsatisfactory doctrine, and there is an alternative to it that is more philosophically defensible, and also more consistent with some other things Wittgenstein said.
The alternative is that there is another criterion of class membership, and when, using this criterion, we assemble some members of any class, we will generally find on surveying them that there are significant resemblances among them, although not generally and certainly not necessarily any one resemblance running through them all.
On this interpretation, the family resemblance doctrine does not provide a new answer to the old question why we call all bedsteads 'bedsteads', but might come as some relief to anyone who could not live with the idea that we should sometimes call things by the same name that resembled one