But it is upon the concept of "certitude" that law as distinct from morality properly, according to Vico, rests. The word certitude is used by him in many senses, neither clearly distinguished nor harmonised nor deduced one from another: though they all as we have seen unite, rather confusedly, in the general idea of the spontaneous as distinguished, from the reflective form of the mind. Certitude in its practical signification implies among other things an opposition to the "truth" of volition, and is, in a word, force as against equity and justice, authority as against reason, mere will as against the moral will. These are distinctions occurring to our own thoughts, rather than stated by Vico, who both distinguishes and fails to distinguish. For instance, he affirms that "certitude proceeds from authority, truth from reason" (_certuni ab auctoritate est, verum a ratione_) and immediately afterwards adds that "it is quite impossible for authority to conflict with reason, for in that case there would be not laws but abortive laws" (_auctoritas cum ratione omnino pugnare non potest, nam ita non leges essent, sed monstra legum_). At any rate, the New Science seems to him, by reason of this treatment of certitude, to contain a philosophy of authority, which, he adds, "is the source of what theological moralists call external justice." That is to say, he connected the concept of certitude with the distinction and terminology of external and internal, already employed by the scholastic morality, which, used about this time by Christianus Thomasius, were destined without any great philosophical merit on his part to give an impetus to the investigation of the philosophical relations between law and morality.