Early on in the Philosophical Investigations, Ludwig Wittgenstein offers his famous example of games to show how many things are united in name by similarities not underscored by any single common feature. He writes:
Consider, for example, the activities that we call “games”. I mean board-games, card-games, ball-games, athletic games, and so on. What is common to them all? — Don’t say: “They must have something in common, or they would not be called ‘games’” — but look and see whether there is anything common to all. — For if you look at them, you won’t see something that is common to all, but similarities, affinities […] I can think of no better expression to characterize these similarities than “family resemblances”; for the various resemblances between members of a family a build, features, colour of eyes, gait, temperament, and so on and so forth — overlap and criss-cross in the same way. — And I shall say: ‘games’ form a family (§§ 66–7).
It has since been customary amongst philosophers to talk of some concepts being ‘family resemblance concepts’. This is problematic, but not for the reasons that Wittgenstein’s detractors assume. The most famous of these is Bernard Suits, who in his playful book The Grasshopper: Games, Life and Utopia states that Wittgenstein ‘saw very little’ before putting forward what he takes to be an adequate definition of ‘ game’ in terms of necessary and sufficient conditions shared by anything worthy of the name.
The book takes the form of stories designed to support his definition:
To play a game is to attempt to achieve a specific state of affairs, using only means permitted by rule, where the rules prohibit use of more efficient in favour of less efficient means, and where the rules are accepted just because they make possible such activity.