In this paper I shall discuss the question, "How did Wittgenstein see the relation between philosophy and science?" This is not a question about his philosophy of science. It is not, for example, directly concerned with the brief account of scientific theories that he gave in the Tractatus.¹ My inquiry is a more fundamental one. I want to uncover his view of the relation between science and philosophy. If he showed scientific discourse, and, more generally, factual discourse on the same map as philosophical discourse, how would he place them? And at how many points did he see a risk of our unwittingly crossing the frontier which divides them?