The Portable Medieval Reader

by James Bruce Ross

  He noted too in regard to logic that it was composed of and reduced to certain rules of argumentation for this reason, namely, lest it lead inconstant minds into error by false inferences, since it seems to construct by its reasons what is not found in the nature of things, and since it seems often to infer things contrary in their conditions, in the following manner: Socrates is body, but body is white, therefore Socrates is white. On the other hand: Socrates is body, but body is black, therefore Socrates is black.

  Moreover in writing logic the following order is extremely necessary, that since arguments are constructed from propositions, and propositions from words, he who will write logic perfectly, must first write of simple words, then of propositions, and finally devote the end of logic to argumentations, just as our prince Aristotle did, who wrote the Categories on the science of words, the On Interpretation on the science of propositions, the Topics and the Analytics on the science of argumentations.

  Porphyry himself moreover, as the very statement of the title shows, prepares this introduction for the Categories of Aristotle, but later he himself shows that it is necessary to the whole art. The intention of it, the matter, the manner of treatment, the utility or the part of dialectic to which the present science is to be subordinated, will now be distinguished briefly and precisely.

  The intention is particularly to instruct the reader in the Categories of Aristotle, that he may be able to understand more easily the things that are there treated. This makes necessary the treatment of the five subjects which are its materials, namely genus, species, difference, property, and accident. He judged the knowledge of these to be particularly useful to the Categories because the investigation is concerning them in almost the whole course of the Categories. That which we spoke of as five, however, can be referred to the words, genus, species, and the others, and also in a certain sense to the things signified by them. For he appropriately makes clear the significance of these five words which Aristotle uses, lest one be ignorant, when one has come to the Categories, of what is to be understood by these words; and he is able, moreover, to treat of all the things signified by these words, as if of five things, since, although they are infinite taken singly, inasmuch as genera are infinite and likewise species and the others, nevertheless as has been said, all are considered as five, because all are treated according to five characteristics, all genera according to what constitutes genera, and the others in the same way, for in this same way the eight parts of speech are considered according to their eight characteristics, although taken singly they are infinite.

  The manner of treatment here is the following: having first distinguished the natures of each singly in separate treatments of them, he proceeds then for further knowledge of them to their common properties and characteristics.

  Its utility, as Boëthius himself teaches, is principally as it is directed to the Categories. But it is spread in four directions which we shall disclose more carefully later when he himself takes it up.

  If the parts of logic have first been distinguished carefully, it is seen at once what is the part through which the science of the present work leads to logic. On the authority of Cicero and Boëthius, there are two parts of which logic is composed, namely, the science of discovering arguments and of judging them, that is, of confirming and proving the arguments discovered. For two things are necessary to one who argues, first to find the arguments by which to argue, then if any should criticize the arguments as defective or as insufficiently firm to be able to confirm them. Wherefore Cicero says that discovery is by nature prior. The present science, however, is concerned with both parts of logic, but most of all with discovery. And it is a part of the science of discovering. For how can an argument be deduced from genus or species or the others, if the things which are here treated are not known? Wherefore Aristotle himself introduces the definition of the predicables into the Topics, when he treats of their places, as Cicero likewise does in his Topics. But since an argument is confirmed from the same considerations from which it is discovered, this science is not unrelated to judgment. For as an argument is derived from the nature of genus and species, so, once derived, it is confirmed from the nature of genus and species. For considering the nature of species in man, so far as it is related to animal, I find at once from the nature of the species the argument for proving animal. But if any one should criticize the argument, I show that it is suitable immediately by indicating the nature of the species and the genus in both, so that from the same conditions of the terms the argument may be found and when it has been found it may be confirmed.

  From Glosses on Porphyry, trans. R. McKeon, Selections from Medieval Philosophers (New York: Scribner, 1929).

  The End of Man

  SAINT THOMAS AQUINAS

  Thirteenth century

  WE HAVE shown in the preceding books that there is one First Being, possessing the full perfection of all being, whom we call God, and who of the abundance of His perfection, bestows being on all that exists, so that He is proved to be not only the first of beings, but also the beginning of all. Moreover He bestows being on others, not through natural necessity, but according to the decree of His will, as we have shown above. Hence it follows that He is the Lord of the things made by Him: since we dominate over those things that are subject to our will. And this is a perfect dominion that He exercises over things made by Him, forasmuch as in their making He needs neither the help of an extrinsic agent, nor matter as the foundation of His work: since He is the universal efficient cause of all being.

  Now everything that is produced through the will of an agent is directed to an end by that agent: because the good and the end are the proper object of the will, wherefore whatever proceeds from a will must needs be directed to an end. And each thing attains its end by its own action, which action needs to be directed by him who endowed things with the principles whereby they act.

  Consequently God, who in Himself is perfect in every way, and by His power endows all things with being, must needs be the Ruler of all, Himself ruled by none: nor is anything to be excepted from His ruling, as neither is there anything that does not owe its being to Him. Therefore as He is perfect in being and causing, so is He perfect in ruling.

  The effect of this ruling is seen to differ in different things, according to the difference of natures. For some things are so produced by God that, being intelligent, they bear a resemblance to Him and reflect His image: wherefore not only are they directed, but they direct themselves to their appointed end by their own actions. And if in thus directing themselves they be subject to the divine ruling, they are admitted by that divine ruling to the attainment of their last end; but are excluded therefrom if they direct themselves otherwise.

  Others there are, bereft of intelligence, which do not direct themselves to their end, but are directed by another. Of these some being incorruptible, even as they are not patient of defects in their natural being, so neither do they wander, in their own action, from the direction to their appointed end, but are subject, without fail, to the ruling of the Supreme Ruler; such are the heavenly bodies, whose movements are invariable. Others, however, being corruptible, are patient of defects in their natural being; yet this defect is supplied to the advantage of another: since when one thing is corrupted, another is generated. Likewise, they fail from their natural direction in their own actions, yet this failing is compensated by some resultant good. Whence it is clear that not even those things which are seen to wander from the direction of the supreme ruling, escape from the power of the Supreme Ruler: because also these corruptible bodies, even as they are created by God, so too are they perfectly subject to Him. . . .

  Since then in the First Book we have treated of the perfection of the divine nature, and, in the Second, of the perfection of the divine power, inasmuch as He is the Creator and Lord of all: it remains for us in this Third Book to treat of His perfect authority or dignity, inasmuch as He is the end and Governor of all. We must therefore proceed in this wise, s
o as first to treat of Him as the end of all things; secondly of His universal government, inasmuch as He governs every creature: thirdly, of that special government, whereby He governs creatures endowed with intelligence.

  Accordingly we must first show that every agent, by its action, intends an end.

  For in those things which clearly act for an end, we declare the end to be that towards which the movement of the agent tends: for when this is reached, the end is said to be reached, and to fail in this is to fail in the end intended; as may be seen in the physician who aims at health, and in a man who runs towards an appointed goal. Nor does it matter, as to this, whether that which tends to an end be cognitive or not: for just as the target is the end of the archer, so is it the end of the arrow’s flight. Now the movement of every agent tends to something determinate: since it is not from any force that any action proceeds, but heating proceeds from heat, and cooling from cold; wherefore actions are differentiated by their active principles. Action sometimes terminates in something made, for instance, building terminates in a house, healing ends in health: while sometimes it does not so terminate, for instance, understanding and sensation. And if action terminate in something made, the movement of the agent tends by that action towards that thing made: while if it does not terminate in something made, the movement of the agent tends to the action itself. It follows therefore that every agent intends an end while acting, which end is sometimes the action itself, sometimes a thing made by the action.

  Again. In all things that act for an end, that is said to be the last end, beyond which the agent seeks nothing further: thus the physician’s action goes as far as health, and this being attained, his efforts cease. But in the action of every agent, a point can be reached beyond which the agent does not desire to go; else actions would tend to infinity, which is impossible, for since it is not possible to pass through an infinite medium, the agent would never begin to act, because nothing moves towards what it cannot reach. Therefore every agent acts for an end....

  Again. Every agent acts either by nature or by intelligence. Now there can be no doubt that those which act by intelligence act for an end; since they act with an intellectual preconception of what they attain by their action, and act through such preconception, for this is to act by intelligence. Now just as in the preconceiving intellect there exists the entire likeness of the effect that is attained by the action of the intellectual being, so in the natural agent there pre-exists the similitude of the natural effect, by virtue of which similitude its action is determined to the appointed effect: for fire begets fire, and an olive produces an olive. Wherefore even as that which acts by intelligence tends by its action to a definite end, so also does that which acts by nature. Therefore every agent acts for an end.

  Moreover. Fault is not found save in those things which are for an end: for we do not find fault with one who fails in that to which he is not appointed; thus we find fault with a physician if he fails to heal, but not with a builder or a grammarian. But we find fault in things done according to art, as when a grammarian fails to speak correctly; and in things that are ruled by nature, as in the case of monstrosities. Therefore every agent, whether according to nature, or according to art, or acting of set purpose, acts for an end....

  There are, however, certain actions which would seem not to be for an end, such as playful and contemplative actions, and those which are done without attention, such as scratching one’s beard, and the like: whence some might be led to think that there is an agent that acts not for an end. But we must observe that contemplative actions are not for another end, but are themselves an end. Playful actions are sometimes an end, when one plays for the mere pleasure of play; and sometimes they are for an end, as when we play that afterwards we may study better. Actions done without attention do not proceed from the intellect, but from some sudden act of the imagination, or some natural principle: thus a disordered humour produces an itching sensation and is the cause of a man scratching his beard, which he does without his mind attending to it. Such actions do tend to an end, although outside the order of the intellect. Hereby is excluded the error of certain natural philosophers of old, who maintained that all things happen by natural necessity, thus utterly banishing the final cause from things.

  Hence we must go on to prove that every agent acts for a good.

  For that every agent acts for an end clearly follows from the fact that every agent tends to something definite. Now that to which an agent tends definitely must needs be befitting to that agent: since the latter would not tend to it save on account of some fittingness thereto. But that which is befitting to a thing is good for it. Therefore every agent acts for a good.

  Further. The end is that wherein the appetite of the agent or mover is at rest, as also the appetite of that which is moved. Now it is the very notion of good to be the term of appetite, since good is the object of every appetite. Therefore all action and movement is for a good.

  Again. All action and movement would seem to be directed in some way to being: either for the preservation of being in the species or in the individual; or for the acquisition of being. Now this itself, being, to wit, is a good: and for this reason all things desire being. Therefore all action and movement is for a good.

  Furthermore. All action and movement is for some perfection. For if the action itself be the end, it is clearly a second perfection of the agent. And if the action consist in the transformation of external matter, clearly the mover intends to induce some perfection into the thing moved: towards which perfection the movable tends, if the movement be natural. Now when we say a thing is perfect, we mean that it is good. Therefore every action and movement is for a good....

  Moreover. The intellectual agent acts for an end, as determining on its end: whereas the natural agent, though it acts for an end, as proved above, does not determine on its end, since it knows not the ratio of end, but is moved to the end determined for it by another. Now an intellectual agent does not determine the end for itself except under the aspect of good; for the intelligible object does not move except it be considered as a good, which is the object of the will. Therefore also the natural agent is not moved, nor does it act for an end, except in so far as this end is a good: since the end is determined for the natural agent by an appetite. Therefore every agent acts for a good....

  Moreover. Whatever is moved is brought to the term of movement by the mover and agent. Therefore mover and moved tend to the same term. Now that which is moved, since it is in potentiality, tends to an act, and consequently to perfection and goodness: for by its movement it passes from potentiality to act. Therefore mover and agent by moving and acting always intend a good.

  Hence the philosophers in defining the good said: “The good is the object of every appetite,” and Dionysius (De Div. Nom., iv) says that “all things desire the good and the best.” ...

  From the foregoing it is clear that all things are directed to one good as their last end.

  For if nothing tends to something as its end, except in so far as this is good, it follows that good, as such, is an end. Consequently that which is the supreme good is supremely the end of all. Now there is but one supreme good, namely God, as we have shown in the First Book. Therefore all things are directed to the supreme good, namely God, as their end....

  Further. In every series of causes, the first cause is more a cause than the second cause: since the second cause is not a cause save through the first. Therefore that which is the first cause in the series of final causes, must needs be more the final cause of each thing, than the proximate final cause. Now God is the first cause in the series of final causes: for He is supreme in the order of good things. Therefore He is the end of each thing more even than any proximate end....

  Furthermore. The particular good is directed to the common good as its end: for the being of the part is on account of the whole: wherefore the good of the nation is more godlike than the good of one man. Now the supreme good, namely God, is the common g
ood, since the good of all things depends on Him: and the good whereby each thing is good, is the particular good of that thing, and of those that depend thereon. Therefore all things are directed to one good, God, to wit, as their end....

  Furthermore. In all mutually subordinate agents and movers, the end of the first agent must be the end of all; even as the end of the commander-in-chief is the end of all who are soldiering under him. Now of all the parts of man, the intellect is the highest mover: for it moves the appetite, by proposing its object to it; and the intellective appetite, or will, moves the sensitive appetites, namely the irascible and concupiscible, so that we do not obey the concupiscence, unless the will command; and the sensitive appetite, the will consenting, moves the body. Therefore the end of the intellect is the end of all human actions. Now the intellect’s end and good are the true; and its last end is the first truth. Therefore the last end of all man and of all his deeds and desires, is to know the first truth, namely God.