As regards natural law, he teaches that God has implanted in the human mind a knowledge of its immutable general principles; and not only knowledge, but a disposition, to which he applies the peculiar scholastic name synderesis,' that unerringly prompts to the realization of these principles in conduct, and protests against their violation.
By the schoolmen, however, the terms were differentiated, conscience being the practical envisaging of good and evil actions; synderesis being, so to speak, the tendency toward good in thought and action.
The exact relation between the two was, however, a matter of controversy, Aquinas and Duns Scotus holding that both are practical reason, while Bonaventura narrows synderesis to the volitional tendency to good actions.
The term synderesis, however, is not found till Jerome, who in dealing with Ezek.