Derivation of positive from natural law revisited

Abstract

Aquinas's account of the relationship of natural law to positive law has a general theory: every just human law is derived from the law of nature; I and two, subordinate theorems: derivation is always either per modum conclusionis or per modum determinationis. I will call them sub-theorems. According to the first sub-theorem "something may be derived from the natural law . . . as a conclusion from premises." For example, "that one must not kill may be derived as a conclusion from the principle that one must do harm to no one." For one reason or another, the theory of derivation per modum determinationis has been the object of more intense study,6 but this Note will focus on the first sub-theorem and its concept: derivation per modum conclusionis...