Hence the Aristotelian logic necessarily assumes certain first or fundamental truths unquestioned and unquestionable, self-evident and self-evidencing, neither established nor modified by thought, but standing firm in their own right. This assumption was not, as modern dealers in formal logic would sometimes have it, an external psychological or metaphysical attachment to the theory of reasoning, to be omitted at will from logic as such. It was an essential factor of knowledge that there should be necessary propositions directly apprehended by reason and particular ones directly apprehended by sense. Reasoning could then join them. Without the truths we have only the play of subjective, arbitrary, futile opinion. _Judgment_ has not taken place, and assertion is without warrant. Hence the scheduling of first truths is an organic part of any reasoning which is occupied with securing demonstration, surety of assent, or valid conviction. To deny the necessary place of ultimate truths in the logical system of Aristotle and his followers is to make them players in a game of social convention. It is to overlook, to invert, the fact that they were sincerely concerned with the question of attaining the grounds and process of assurance. Hence they were obliged to assume primary intuitions, metaphysical, physical, moral, and mathematical axioms, in order to get the pegs of certainty to which to tie the bundles of otherwise contingent propositions. It would be going too far to claim that the regard for the authority of the church, of the fathers, of the Scriptures, of ancient writers, of Aristotle himself, so characteristic of the Middle Ages, was the direct outcome of this presupposition of truths fixed and unquestionable in themselves. But the logical connection is sure. The supply of absolute premises that Aristotle was able to proffer was scant. In his own generation and situation this paucity made comparatively little difference; for to the mass of men the great bulk of values was still carried by custom, by religious belief, and social institution. It was only in the comparatively small sphere of persons who had come under the philosophic influence that need for the logical mode of confirmation was felt. In the mediaeval period, however, all important beliefs required to be concentrated by some fixed principle giving them stay and power, for they were contrary to obvious common-sense and natural tradition. The situation was exactly such as to call into active use the Aristotelian scheme of thought. Authority supplemented the meagerness of the store of universals known by direct intuition, the Aristotelian plan of reasoning afforded the precise instrumentality through which the vague and chaotic details of life could be reduced to order by subjecting them to authoritative rules.