I argue that explanations of doxastic transparency which go via an appeal to an aim or norm of belief are problematic. I offer a new explanation which appeals to a biological function of our mechanisms for belief production. I begin by characterizing the phenomenon, and then move to the teleological and normative accounts of belief, advertised by their proponents as able to give an explanation of it. I argue that, at the very least, both accounts face serious difficulties in this (...) endeavour. These difficulties are a function of seeking an explanation of transparency at the agential level, either with the subject aiming at truth, or being guided by a norm of truth. I adopt a motivational account of belief, one which severs the connection between belief and truth, and supplement this with an account of actual world beliefs. My alternative explanation is found at the sub-intentional, non-agential level, secured by biology. This explanation casts transparency not as related to the nature of deliberation over what to believe, but rather as contingently characterizing the beliefs of some believers, namely those with a particular biological history. My explanation thus parts company with what has come before along two dimensions: it moves away from transparency being something related to the agent’s aims or commitments, and it understands it as a contingent phenomenon. I close by considering an objection to my view—that transparency must not be understood as a contingent phenomenon—and a nearby alternative position which avoids this consequence. I respond to this objection and give reasons not to endorse the nearby alternative. I conclude that my explanation does not face the difficulties of those offered by teleologists and normativists, and, that by moving away from agential explanations, and casting transparency as contingent, we can provide a successful explanation of it. (shrink)