What are thought experiments, and how do they generate knowledge? More specifically, what sorts of intentional acts must one perform in order to carry out a thought experiment, what sorts of objects are such acts directed toward, and how are those objects made present in such acts? I argue on phenomenological grounds that the proper objects of thought experiments are, in certain cases, uninstantiated universals and relations among them. I will also argue that, in the best of cases, we intuit or “see” these universals and their relations to one another, and respond to some objections to this view.