For Pascal, our knowledge of everything from geometry and the external world to God comes not from reason or experience alone, but rather it requires a feeling of “the heart.” This central notion in Pascal, which is underexplored in the literature, is the key to understanding his philosophy. This chapter develops a “cordate” (or heart-shaped) epistemology to show how the heart replaces reason and experience as the foundation in Pascal. Once we piece together an account of the heart – no easy task, since Pascal’s notes do not explicitly define it – we can trace its role in generating belief. The heart is, roughly, an affective orientation that is the seat of the will, which in turn affects experience, feelings, and perception. It even generates its own reasons. This affective orientation includes, for example, what one fundamentally loves, hates, fears, and so on. We can then see how a feeling of the heart can generate knowledge of first principles, that we are not dreaming, and, once we consider the role of the heart in Pascal’s Augustinian theology, a kind of religious engagement with the world and ultimately a love (and consequently knowledge) of God. Applications to life today are also explored.