ACCORDING to established popular usage, which the Philosopher considers should be our guide in the naming of things, they are called 'wise' who put things in their right* order and control them well. Now, in all things that are to be controlled and put in order to an end, the measure of control and order must be taken from the end in view; and the proper end of everything is something good. Hence we see in the arts that art A governs and, as it were, lords it over art B, when the proper end of art B belongs to A.* Thus the art of medicine lords it over the art of the apothecary, because health, the object of medicine, is the end of all drugs that the apothecary's art compounds. These arts that lord it over others are called 'master-building,' or 'masterful arts'; and the 'master-builders' who practise them arrogate to themselves the name of 'wise men.' But because these persons deal with the ends in view of certain particular things, without attaining to the general end of all things, they are called 'wise in this or that particular thing,' as it is said, 'As a wise architect I have laid the foundation' (I Cor. iii, 10); while the name of 'wise' without qualification is reserved for him alone who deals with the last end of the universe, which is also the first beginning of the order of the universe. Hence, according to the Philosopher, it is proper to the wise man to consider the highest causes.
Now the last end of everything is that which is intended by the prime author or mover thereof. The prime author and mover of the universe is intelligence, as will be shown later (B. II, Chap. XXIII, XXIV). Therefore the last end of the universe must be the good of the intelligence, and that is truth. Truth then must be the final end of the whole universe; and about the consideration of that end* wisdom must primarily be concerned. And therefore the Divine Wisdom, clothed in flesh, testifies that He came into the world for the manifestation of truth: For this was I born, and unto this I came into the World, to give testimony to the truth (John xvii, 37). The Philosopher also rules that the first philosophy is the science of truth, not of any and every truth, but of that truth which is the origin of all truth, and appertains to the first principle of the being of all things; hence its truth is the principle of all truth, for things are in truth as they are in being.
It is one and the same function to embrace either of two contraries and to repel the other. Hence, as it is the function of the wise man to discuss truth, particularly of the first beginning, so it is his also to impugn the contrary error. Suitably therefore is the double function of the wise man displayed in the words above quoted from the Sapiential Book, namely, to study, and upon study to speak out the truth of God, which of all other is most properly called truth, and this is referred to in the words, My mouth shall discuss truth, and to impugn error contrary to truth, as referred to in the words, And my lips shall detest the ungodly.
1.2 : Of the Author's Purpose