By "positivism" (which can mean many things) I mean here a stance which prizes science for its ability to both produce reliable knowledge and contribute crucially to human flourishing. By "fling" here I mean merely a temporary attachment. Nietzsche was, by any definition, an ardent anti-positivist for most of his philosophical career. My thesis here is that he can nevertheless be described as a positivist (at least in the above sense) during a certain phase in (what must now be called) his philosophical development. I am thus arguing that we must periodize Nietzsche with regard to issues of science and epistemology: positivism belongs to Nietzsche's middle phase, beginning with Human,All Too Human (published in 1878) and concluding some time before The Gay Science (published in 1882). The connotation of "fling" as being somewhat fleeting and not especially serious or heartfelt is also intended, for not only does Nietzsche give up his positivism after a short time, but even while professing it holds at the same time some of the views which will develop into the perspectivism for which he is better known in his later works.