While Kant’s account of humankind’s rational progress has been widely discussed, his speculative views about the way in which this progress might have begun and the circumstances surrounding this beginning have been largely neglected. Implicit in such an omission is the assumption that Kant does not say much about the very beginning of human history or that whatever he says is of little philosophical value. This article challenges these assumptions. I reconstruct Kant’s account of the emergence of reason by looking at his various conjectural and more literal remarks about our species’ transition from mere irrational animals into primitive human beings possessing a rudimentary form of rationality. Next, I show how this account fits with Kant’s broader view of humankind’s rational progress and its subsequent stages. By doing so, I elucidate Kant’s guidelines for achieving this progress in the future by unifying them with his regulative view of reason’s past.