 But one might be wondering how it is that culpable ignorance is even possible where it relates to general moral principles. How can one go wrong about the universal premises that form the major premise of the practical syllogism, which are drawn from the precepts which comprise the natural law, if synderesis, which grasps such premises, is infallible? Aquinas’s answer is that there are two types of natural law precepts: primary—or those which are “most general”—and secondary. Aquinas is less specific on this topic than is optimal, but in drawing this distinction he seems to mean something like the following. About the primary precepts of the natural law, no-one can go wrong. Unfortunately, as we have seen, such precepts are of a very general character, such as “do good and avoid evil”. For such general knowledge to be applicable by conscience, it must be further specified. This further specification comprises the secondary precepts of the natural law, which are closely drawn from the former precepts and from natural inclination. About such secondary, derived precepts of the natural law, such as “adultery is to be avoided”, humans are all too prone to become ignorant. For Aquinas such ignorance is the result either of vice or of having been socialized in a culture with “vicious customs”: