In this paper, I have made an attempt to understand the concept of moral certainty in Descartes’ philosophy. This concept has not received much attention in the Cartesian scholarship. I argue that Descartes entertains a certainty, called moral certainty, which is a lesser certainty than metaphysical certainty, which we see in his text, Meditations. Only a few Cartesian scholars have talked about this concept in relation to other areas in Descartes’ philosophy. In this paper, I draw a relationship between the (...) concept of moral certainty and the faculty of reason in the context of Descartes’ text, Discourse. I argue that Descartes entertains the testimonies of learned men when it comes to practical or moral matters, arguing that their testimonies guarantee moral certainty. I argue that Descartes claims, in the Discourse, that human beings are endowed with the faculty of reason on the basis of moral certainty. (shrink)