The thesis defended in this article is that epistemology should treat some of our cognitive limitations not as unfortunate defects or external perturbations to be idealized away in theories of epistemic agency, but as necessary underpinnings of good reasoning. We begin with a problem regarding deliberation that calls epistemic agency into question: our reasons in support of belief are never conclusive and never rule out all doubt. Yet we must rule out all doubt to close deliberation; we must close deliberation (...) to form a full belief; and we must form a full belief to have knowledge. The problem with the first step calls the whole into question. The solution (if we seek an alternative to rejecting traditional epistemic agency, including the existence of beliefs) is our limitations: they prevent us from considering all possible doubt, leaving a tractable space of possibilities. When these limitations are virtuous, they contribute to an effective cognitive system. Once we understand the role of our limitations, it will lead us to a deeper understanding of deliberation, belief, epistemic virtue, and epistemic agency. Limitations are as much a part of agency as, for example, logical relations are. Idealizing them away means idealizing away actual agency. (shrink)