The familiar phrase in my title is usually understood as indicating that one has already experienced the topic under discussion and become bored with it. Here it flags the view, first, that all portions of humanity go through essentially the same historical stages that can be identified in the history of the West, and thus that, whatever our non-Western contemporaries may now be experiencing, the West has already 'been there, done that'. This view also underlies the patronizing assumption that many in the non-Western world belong in the past of the Western present, that they are likely to have a poor understanding of their own pasts, which are merely truncated or incomplete forms of the past of the West itself. This destructive view, which is commonly, but not always, associated with a sense of Western superiority, is one of the foundations of modern Western cosmopolitanism. In this paper, I take the destructiveness of this view as a given and aim, rather, to explore its origins. I suggest that the most important of these are to be found in the early history of European imperialism.