|Aquinas Day By Day|
Aquinas’s topic: Logic is an art and a science
Scripture: “The law of the Lord is perfect, refreshing the soul; the decree of the Lord is trustworthy, giving wisdom to the simple.” Psalm 19:
Aquinas’s text: Prologue, Expositio libri posteriorum, written 1271-2
Br. Thomas here introduces logic by pointing out that it has two sides, it is an Aart,” a craft absolutely essential for human life, and it is a “science,” a discipline that can be mastered by systematic study.
As Aristotle says at the beginning of his Metaphysics, the human race lives by art and reasoning. In this claim, the Philosopher is seen to touch on a certain property that distinguishes a human from the other animals. For the other animals are prompted to their actions by a certain natural instinct, but in his actions a human is directed by the judgment of reason. This is why the different arts serve the end of making human actions be performed with facility and order. For an art is seen to be nothing else than a set ordination coming from reason wherein through definite means human actions can arrive at a due end.
Now not only can reason direct the acts of inferior parts of the soul, but it also directs its own acts, for it is proper to the intellective part of the soul that it reflect on itself. For the intellect understands itself and likewise reason can reason about its own act. Therefore, if the fact that reason thinks about the action of the hand led to the invention of the crafts of the builder and carpenter, by which a human can engage in these sorts of actions with facility and order, for the same reason it is necessary that there be an art that directs the acts of reason itself, in order that a human engage in the act of reasoning with order and facility, and without error.
This art is logic, that is , the science of reasoning. Now it is rational, not only in the sense that it follows reason, for all the arts do this, but also in the sense that it concerns the very act of reasoning as its proper matter. Therefore, it is seen to be the ‘art of arts,’ since it directs us in the act of reasoning, which is the source of all the arts.
Sicut dicit Aristoteles in principio metaphysicae, hominum genus arte et rationibus vivit: in quo videtur philosophus tangere quoddam hominis proprium quo a caeteris animalibus differt. Alia enim animalia quodam naturali instinctu ad suos actus aguntur; homo autem rationis iudicio in suis actionibus dirigitur. Et inde est quod ad actus humanos faciliter et ordinate perficiendos diversae artes deserviunt. Nihil enim aliud ars esse videtur, quam certa ordinatio rationis quomodo per determinata media ad debitum finem actus humani perveniant.
Ratio autem non solum dirigere potest inferiorum partium actus, sed etiam actus sui directiva est. Hoc enim est proprium intellectivae partis, ut in seipsam reflectatur: nam intellectus intelligit seipsum et similiter ratio de suo actu ratiocinari potest. Si igitur ex hoc, quod ratio de actu manus ratiocinatur, adinventa est ars aedificatoria vel fabrilis, per quas homo faciliter et ordinate huiusmodi actus exercere potest; eadem ratione ars quaedam necessaria est, quae sit directiva ipsius actus rationis, per quam scilicet homo in ipso actu rationis ordinate, faciliter et sine errore procedat.
Et haec ars est logica, idest rationalis scientia. Quae non solum rationalis est ex hoc, quod est secundum rationem (quod est omnibus artibus commune); sed etiam ex hoc, quod est circa ipsum actum rationis sicut circa propriam materiam. Et ideo videtur esse ars artium, quia in actu rationis nos dirigit, a quo omnes artes procedunt.
[Introductions and translations © R.E. Houser]