The Early Wittgenstein's Atomic Logic, Categories and the Necessary A posteriori

Kant linked the necessary and the a priori, taking them to be equivalent in extension. In the Tractatus, Wittgenstein, I argue, severed this Kantian link decades before Kripke. This is because, I explain, Wittgenstein held that even though the categories of atomic objects are necessary, they aren’t a priori, but, in a certain sense, a posteriori. To make my case I develop an interpretation of the ontology and epistemology of the Tractatus before charting the philosophical route whereby Wittgenstein travelled from his starting position in the ‘Notes on Logic’ (1913) via the Notebooks (1914–1916) to arrive at his destination, his conception of the categories in the Tractatus.