I have always wondered why Feyerabend makes very little mention of Nietzsche, when for me their philosophies are so close. Often in his treatment of Ernst Mach I discerned an unthematised Nietzschean element. So it was with great satisfaction that I stumbled upon this passage from a letter by Feyerabend to J.J.C. Smart:
« In his earlier life Nietzsche was very much interested in the philosophy of nature and he intended at some point to write a systematic treatise on this topic. He adopted for some time Mach’s point of view and he interpreted this point of view as showing that the world in which we live (our perceptual world) is a mental construction, and that different kinds of mental construction are possible. This brings him at places rather close to Wittgenstein. » (NATURPHILOSOPHIE, p330)
I would add that this proximity to Mach existed all through Nietzsche’s philosophical development, and is not limited to his early work.