Politics has been defined in different and contradictory ways in the last century or so. If politics is to be a single subject of study then contradictory theories should be capable of being related together. In this article I argue that they can be related in terms of what I call the Aristotelian criterion. The article is in four parts. Firstly, I discuss the problem of defining politics; secondly, I introduce the criterion; thirdly, I consider five modern theories of politics (...) (those of Arendt, Oakeshott, Collingwood, Schmitt and Rancière) in relation to the criterion; and fourthly, I use the criterion to put forward an original and capacious definition of politics.1. (shrink)