Abstract
In this paper, I will introduce the notions of crucial argument and crucial evidence in the philosophy of intellectual history (broadly construed, including the history of political thought). I will use these concepts and take sides in an important controversy in Hobbes studies, namely whether Hobbes holds a prudential or a deontological theory of contractual obligation. Though there is textual evidence for both readings, I will argue that there is especially relevant evidence crucial evidence - for interpreting Hobbes's account in a deontological fashion.