Family resemblance is a philosophical idea made popular by
Ludwig Wittgenstein, with the best known exposition given in his posthumously published book
Philosophical Investigations (1953). It argues that things which could be thought to be connected by one essential common feature may in fact be connected by a series of overlapping similarities, where no one feature is common to all. Games, which Wittgenstein used as an example to explain the notion, have become the paradigmatic example of a group that is related by family resemblances. It has been suggested that Wittgenstein picked up the idea and the term from
Nietzsche, who had been using it, as did many nineteenth century philologists, when discoursing about
language families.