This thesis is about the relationship between a belief being justified and it being true. It defends a version of the view that the fundamental point of having a justified belief is to have a true one. The particular version of that view it defends is the claim that belief is subject to a truth norm – i.e. a norm or standard that says that one should believe something if and only if it’s true. It claims that belief being subject to such a truth norm can explain which beliefs count as justified and which do not.

After introducing the idea of a truth norm (Ch. 1), the argument of my thesis involves two main stages.

Part One of the thesis (Chs. 2-3) contains the first stage, in which I argue that my way of arguing for a truth norm, on the basis of its explanatory role in epistemology, is much more likely to be successful than a more popular way of arguing for a truth norm, on the basis of its explanatory role in the philosophy of mind.

Part Two (Chs. 4-7) contains the second stage, in which I argue that the truth norm can indeed explain justification in the way I’ve outlined. I do this by answering four criticisms that have been made of the claim that belief is subject to a truth norm. These criticisms claim that a truth norm should be rejected because, in turn, a truth norm cannot guide belief formation (Ch. 4), because a truth norm prescribes believing all the truths (Ch. 5), because a truth norm never prescribes suspending judgement (Ch. 6), and because a truth norm in some cases prescribes making problematic trade-offs of having one false belief for the sake of having many true beliefs (Ch. 7). I argue that all of these criticisms fail. But it is through answering these criticisms that we can see the contours of a defensible explanation of justification in terms of the truth norm.