Friedrich Nietzsche, 100 years after his death, remains a controversial figure in philosophy. Much of this controversy stems from Nietzsche's view of truth, which seems superficially hopelessly contradictory, vacillating between relativism and denial of truth on the one hand, and praise for science and hard truths on the other. Thus, any person wanting to defend Nietzsche's positive philosophy must first make sense of his epistemology. The solution to this puzzle regarding Nietzsche's theory of truth is the realization that Nietzsche changes his view on truth. Much like Wittgenstien, Nietzsche had an early and a late period in his epistemic views, and a middle period where he is struggling with two very different, incompatible views. The late view of truth is surprisingly straightforward: Nietzsche can be seen as an early pragmatist. Once we have a coherent truth theory, we can then start to conclude some of the more contentious arguments in Nietzsche's philosophy, such as: what is the Will to Power, and how does Nietzsche's view of truth interact with his criticism of morality? This thesis will trace the development of the former and endeavor to answer some of the latter.

I show that we have reason to believe a view on scientific theory change can be discerned in what I call the “Copernicus passages” of Nietzsche’s published work—specifically, the incommensurability thesis. Since this view denies what Maudemarie Clark calls the “equivalence principle,” she claims incommensurability cannot reasonably be attributed to Nietzsche. I argue, however, that we can reasonably attribute incommensurability to Nietzsche in the Copernicus passages, so my reading should not be ruled out. The first upshot to this project is that I provide a reading of passages that have received no scholarly attention to date. The second upshot is that we can understand Copernicus in light of the broader, better-known themes in Nietzsche’s published work: Nietzsche’s moral skepticism about the value of self-denial motivates his opposition to the ascetic ideal and to the emerging dogmas of scientists.

Friedrich Nietzsche, 100 years after his death, remains a controversial figure in philosophy. Much of this controversy stems from Nietzsche's view of truth, which seems superficially hopelessly contradictory, vacillating between relativism and denial of truth on the one hand, and praise for science and hard truths on the other. Thus, any person wanting to defend Nietzsche's positive philosophy must first make sense of his epistemology. The solution to this puzzle regarding Nietzsche's theory of truth is the realization that Nietzsche changes his view on truth. Much like Wittgenstien, Nietzsche had an early and a late period in his epistemic views, and a middle period where he is struggling with two very different, incompatible views. The late view of truth is surprisingly straightforward: Nietzsche can be seen as an early pragmatist. Once we have a coherent truth theory, we can then start to conclude some of the more contentious arguments in Nietzsche's philosophy, such as: what is the Will to Power, and how does Nietzsche's view of truth interact with his criticism of morality? This thesis will trace the development of the former and endeavor to answer some of the latter.