In the Metaphysics, Aristotle pointed out that some activities are engaged in for their own sake, while others are directed at some end. The test for distinguishing between them is to ask "At any time during a period in which someone is Xing, is it also true that they have Xed?". If both are true, the activity is being done for its own sake. If not, it is being done for the sake of some end other than itself. For example, if I am thinking, it is true that I have thought. But if I'm making a blouse, it is not true that I have made a blouse, at least not this particular blouse. That's not true until I have completed the project.¹