Chapter IV. Concerning what logic is about as its subject?

Chapter IV. Concerning what logic is about as its subject?

But since logic is a contemplative science, teaching how, and through what things, one comes through the known to knowledge of the unknown, it is necessarily fitting that logic be concerned with an instrument of reason of this sort, through which science of the unknown is acquired through the known in every case in which something known is effected concerning the unknown. But this is argumentation, insofar as argumentation is a reasoning arguing with and convincing the mind, through the relation of the known to the unknown, concerning science of the unknown. But among the species of argumentation the chief is syllogism. For this reason certain men said that logic as a whole is concerned with syllogism and the parts of syllogism ¹, determining the common subject of logic according to that which is the principal subject. For there will not be credibility concerning all things through syllogism, because syllogistic discourse is only from a universal taken universally; and this cannot exist in many sciences, as in rhetorical matters. The reason is that in those matters local relations are especially attended to, from which, through enthymemes, that which was sought is concluded. Therefore since logic, as Aristotle says, gives to every science the mode of discussing, finding, and judging what has been sought, it must be about such a thing as its subject, something which is equally applicable to all things in every case. Moreover there are some things in which from singulars we seek to find what is unknown, as in experimental matters, in which we use either syllogism or induction for receiving the universal, and cannot use perfect syllogism. For this reason syllogism cannot be the common subject of logic. For this reason also, in the logical writings which were written by the Ancients, there is taught not only what syllogism is, and of what sort, and from what things it is, but here there is also taught what argumentation is, and what its parts and species are.

Nevertheless there are those who interpret logic as the same as sermocinal science, saying that general logic is the same as sermocinal science, under which they say grammar, poetics, rhetoric, and the science which they call dialectic are contained. And therefore they say that the subject of general logic is speech, insofar as it is designative of the things which are signified through it. Avicenna attacks this opinion ², saying that speech signifies nothing of itself; for if it signified something of itself, it would always and among all people signify that thing, which is false. Therefore it receives signification from the convention of the one instituting it. Therefore it signifies only according as it has been conceived in the intellect of the one instituting it. Man uses such speech, insofar as it is thus significative of what has been conceived, toward himself and toward another. For this reason Damascene says that it is divided into two, namely into encordial speech, that is, speech disposed inwardly in the mind, and into that which is from signs, which in being understood is a messenger of his heart, because it announces the concept of the heart to another. For this reason the logician uses speech both toward himself and toward another accidentally and not through itself, because without designative speech he cannot proceed to knowledge of that which is unknown ³. But he uses reasoning through itself for producing knowledge of that which has been declared. For this reason, since the intention of the logician is to teach those things through which, through themselves, one comes into knowledge of the unknown through what is known, the subject of logic is argumentation, because through argumentation that which is intended is effected.

Again, although incomplex speech designates something before the simple intellect, nevertheless it does not make faith as to whether something is or is not, because it does not signify that something is or is not. But one does not come to knowledge of the unknown except through something which makes faith concerning the unknown, that it is so or is not so. Therefore incomplex speech cannot be the instrument through which the intellect is led from the unknown to knowledge, which is what the logician principally intends. Therefore incomplex speech is taken up by the logician only accidentally, insofar as it is a part of complex speech, which is designative of composed intellect.

Further, complex speech, in that it is complex, signifies neither being nor non-being; for if this were so, every complex speech would signify that a thing is or is not, and thus a deprecative, optative, or subjunctive utterance would signify that a thing is or is not, which is false. Therefore complex speech, through the fact that it is enunciative, signifies that a thing is or is not. But through the fact that it signifies that a thing is or is not, it does not have the power to argue and to make faith concerning the enunciated thing. Therefore through the fact that it is enunciative, it is not the instrument through which the logician obtains what he intends. But it makes faith through the fact that it is collective toward the form of an argument. Therefore argumentation is the instrument of the logician. But general logic, teaching concerning this, has as its subject that through which the logician using it comes into science of the unknown through the known. Therefore argumentation is the proper subject of teaching logic. And this is the opinion of the three Philosophers, namely Avicenna, Alfarabius, and Algazel.

Nevertheless all sermocinal sciences use speech, namely grammar, poetics, rhetoric, and the science which is called logic. Grammar uses it insofar as a mode of inflections and constructions exists as simply designative of simple and composed intellect, without its knowing concerning the thing signified whether it is or is not. But poetics uses it insofar as the pronounced measure provokes the hearer, by delight or by aversion, to doing or fleeing something; on account of this, from varied compositions and according to metalogy or fable, it fashions, attempting lies which provoke hearers. Rhetoric uses speech insofar as it is designative of that through which it intends to persuade. But the logician alone uses speech insofar as it is a part of the instrument through which alone faith is made concerning the unknown, when knowledge of it is argued from the known through the joining of an argument. Therefore he uses speech on account of another thing, and not on account of speech itself.

But the proof of this is that the known, through which science of the unknown is received, is considered in two ways, namely insofar as it is a thing taken outside the soul of the knower, and insofar as it is a certain notion in the soul of the knower. But it does not make knowledge of the unknown insofar as it is a thing taken outside the soul of the knower, but rather insofar as it is a notion of the thing existing in the soul of the knower; for thus it is significative and inferential of that which is unknown, which unknown the intellect itself in some way perceives with perfect comprehension. Therefore the logician considers significative words of things in this way and not otherwise. I say with perfect comprehension, because perhaps there are some so keen-sighted that from the understanding of one complex utterance they immediately conceive faith concerning the unknown; but this is imperfect and not general. And therefore it does not suffice, but there is need of argumentation perfectly effecting this. But if someone asks whence that known thing is produced from which science and faith of the unknown are received, this is to ask nothing, because in anything there is something known through itself to man and implanted by nature, through which he can receive science of the unknown. Otherwise man would be perceptive of no science or discipline, just as neither is a brute animal, if the first principles of knowing were not present in man through themselves. Therefore logic as a whole is concerned with argumentation or syllogism as its subject. But it is concerned with other incomplex words on account of that.

CHAPTER IV.

Whether universals are corporeal?

The second question is whether universals are incorporeal or corporeal, which has been brought in from the Platonists just as the first was. For Plato used to say that mathematical lines and surface are certain separated things, out of which mathematical bodies are composed; just as he said that every divisible thing is composed out of indivisibles, taking these things from the Epicureans who had begun to philosophize earlier. But Melissus and Parmenides and certain others said such things. And from mathematical great and small things they said that every material quantity consists.

But they introduced three especially strong reasons for their opinion. The first of these was that they saw that substance, both matter and form, of itself, and insofar as it is substance, and taken according to itself, is indivisible, as Aristotle expressly says ⁴. Therefore there must be another indivisible principle of divisibility. But the divisible is nothing except quantity: and every quantity, whether it is discrete or continuous, proceeds only from an indivisible. Further, every species of quantity proceeds only from a proximate indivisible: because each genus and species is caused by some of its own proximate principles. For a body, which is divisible in every way, cannot be caused, as from the proximate principle of its own constitution, by that which is indivisible in every way, such as a point, or by that which is divisible in one way only, such as a line. But it must be caused by that which is divisible in several ways. Such is a surface, which is indivisible only in depth, but divisible in breadth and length. And from the composition of one surface with another it becomes divisible in depth: just as a point, indivisible in every way, by the composition of point with point becomes divisible in length, by the straight motion of a point into a continuum. For a point is substance having position, and therefore by its motion into a continuum it makes the division of a posited line. And similarly it is concerning a surface constituted from a line moved in breadth: that motion composes the line with another existing as one first moved in the breadth of the continuum which is constituted by its motion. And similarly it is concerning a body, which is constituted by the motion of a surface moved in depth. And because there are not more positions of the continuum into which something indivisible could be moved for the constitution of quantity, therefore there are not more than three species of continuous quantity, and not more than three diversities. But since sensible matter is of itself indivisible and immobile, it cannot be the principle of a quantified thing or of quantity. For matter of itself has nothing of quantity. But it is necessary that everything which is an essential principle of some genus be something of that genus, both in the genus of substance and in the genus of accidents. But it has been proved in the Physics ⁵ that the principles of corruptible things are incorruptible, and the principles of sensible things are insensible. Because otherwise in principles and the principles of principles one would go to infinity. It is also clear that those natures which are called simple and universal are principles of those things which are singular, as has already been had and determined in the preceding question. And they cannot be principles of these material and corporeal things unless they are corporeal and determined by principles of quantity. Therefore it follows of necessity, as it seems, that universals are corporeal, and bodies measured by corporeal quantities; and this reason is directly according to Plato's intention, who posited such separated things. And therefore it has been explained by us through many points, so that what he intends may be better understood.

The second reason is that the principle of some genus or species cannot be either this or that determined thing in number: because thus it would not be the universal of that genus or species taken. Therefore the principles of genera and species are genera and species: and since the things principled are sensible and quantified bodies, it follows that their principles are genera and species of quantities. For these are sensible principles individuated by here and now. For substance insofar as it is substance, in its principles, is determined or individuated neither to here nor to now: and therefore it is not caused by such principles. And therefore Plato said that the principles of all these sensible things are about mathematical things taken in the notions of genera or species; but that substance, insofar as it is substance, is not as what is principled, but is determined through quantity to here and now. From this, moreover, he further inferred that genera and species, which are the principles of these singulars, are corporeal.

The third reason of Plato was: because what is first in the order of nature is the cause and principle of the same thing which, according to itself, is posterior in the same order of nature, as has been proved in the Book of the Fount of Life and in the Book of Causes. But the quantified thing taken according to the notion of quantity is clearly prior according to the order of nature to this sensible quantified thing. Therefore, according to the order of nature, it is its cause and principle. But nothing is cause and principle except what is a simple and universal principle. Therefore what is simple and universal is quantified and corporeal.

Without doubt, these are Plato's reasons in this, that he said universals are certain corporeal things constituted in mathematical notions and forms. But what certain people say concerning universals of immaterial things, such as angels and souls, is of no value at all for the present matter. For Plato said that such things stand from eternity, and are certain rays of the first light, and are not caused by material principles through composition; and in such things he said there is particular, not universal: but in such things he said that they are in us through this, that their lights and essences are in us, whether we are existing through them or knowing them. On account of this Avicenna in his Metaphysics, where he establishes the species of quality, says that this saying is true. He gives as its sign: because those things in which they are, whether the things existing through them or knowing them, do not receive them according to here and now, but everywhere and always, as far as they themselves are concerned. For the soul is not in the body according to here and now, nor is a daemon or intelligence, or even an angel, in that in which it is by operation or cognition as here and now, but according to the possibility of that in which it is, it is in it according to everywhere and always: because it does not have in it a discretion of position. This is Plato's opinion.

Against this, three reasons also suffice, which among the many which can be adduced are the stronger. The first of these is that if universals, the principles of these singulars, are corporeal, they are principles either insofar as they are incorporeal, or they are principles of them insofar as they are corporeal and determined here and now. If they are principles of these insofar as they are corporeal, but a corporeal thing is not made corporeal except through another corporeal thing, and the constituting principle is also corporeal, then that corporeal thing itself also is not made corporeal except through another corporeal thing: and thus one would proceed to infinity. Therefore it follows that the principle of a corporeal thing is incorporeal, just as the principle of the corruptible is incorruptible, and the principle of the sensible is insensible, and the principle of the movable is immobile, and so with all other things.

The second reason is that if universals are corporeal, it follows that they are determined by quantities and figures. But the notions of quantities are not quantified, and the notions of figures are not figured. But if universals are quantified and figured, it follows that the one receiving them is figured by them and stretched out by quantity. But the possible intellect receives such things. Therefore the possible intellect will be quantified and figured, which no one has ever supposed, because all praised Anaxagoras when he said that intellect is pure and unmixed, having nothing common with anything. Therefore the universal cannot be corporeal, even in a corporeal thing, since, insofar as it is universal, it is mover of the possible intellect.

The third reason is that if a universal is a body or is corporeal having quantity, its corporeal quantity must also be perpetual. But its singular in which it is, in whatever way, is corporeal and a body: therefore either these two are one body, or they are two bodies. If they are one and the same, it follows that the corruptible is incorruptible, the sensible insensible, the maker made, and the constituting constituted, if they are one and the same: which is unfitting and unintelligible. But if they are two bodies, it follows that two bodies are in the same place. For place is given to mathematical things just as to physical things, as Aristotle says. But it has been proved by us in the Physics that if two bodies are in the same place, of necessity the two will be one and the same body. Therefore it follows that if they are two diverse bodies, they are one and the same body: which is altogether impossible.

But we, determining the things introduced, distinguish that corporeal is said in multiple ways, namely in four ways. In one way something is called corporeal as stretched out by corporeal quantity, so that the quantity itself is also something of it. And thus all things having corporeal quantity, both movable and sensible things, are called corporeal. In a second way things are called corporeal not indeed as having quantity as something of themselves, but nevertheless as stretched out according to the extension of quantity in the subject receiving them, as whiteness and blackness, heat and coldness, and figure, and a form standing about something, are called corporeal, although quantity is nothing of their essence. In a third way everything determined to a body as to a receiver is called corporeal, such as sense and imagination and the other sensible powers. And universally every sensible and vegetative soul are corporeal forms. In a fourth way something is called corporeal, not because it is something of a part or of corporeal quantity, but because it is a principle of the body's quantity. And thus a point is said to be corporeal. But incorporeal is likewise said in many ways: because if one of opposites is multiple, so is the remaining one. In none of these modes is the universal corporeal: because it is as the nature of a body or of a corporeal thing, to which universal being happens through aptitude for being said of many: and it is incorruptible, because, as has been shown very well, otherwise it could not be mover of the possible intellect, because it is utterly incorporeal and incorruptible. For it is a simple notion and nature abstracted from every quantity of extension.

To this, therefore, which is first objected, one must say that that which constitutes the essence of the quantified is twofold, namely according to the essence of quantity and the constitution of that which is quantified or quantity. And from such a principle the objection proceeds and is necessary. Another is the constitution of the quantified according to specific being and notion, not according to that which is quantity and gives the name and definition of quantity. And this principle constituting the species and genus of quantity is not quantity or quantified, but rather the simple nature and notion of quantity. And this nature, thus taken in its simplicity, is a universal.

To that which is introduced second, one must say that what they posit, that the principle of this is simply true, in being and species according to nature or in genus is not determined to this or that: because if this were true, it would not be a universal principle, but a principle of this or that. But this principle is not mathematical quantity in those things which are corporeal; rather it is simple nature constituting in genus and species, and giving name and notion. And in this it is clear that although a point is the essential and as it were material principle of a line, nevertheless it does not have the name or notion of the form of line. But there is another principle according to form, by which a line has the name and notion of line. And this principle taken simply is the nature of line, to which being universal happens through this, that that nature is communicable to many. Therefore it is clear that the universal of corporeal things is incorporeal. And this is the true saying of the Peripatetics.

To that which they introduce third, one must say that what is posited is true, provided it is understood well: that what is essentially a principle by the mode of a material constituted thing is essential, not first in the order of nature; even if it were granted that they constituted and principled natural bodies, they would not principle them except according to that which is subjected quantity, and not according to this by which quantity is in notion or species or genus. And therefore they are not proper to them according to the formal order of nature, or according to the order of efficient cause. But those things which constitute things that are corporeal in notion, name, species, and genus, are prior according to the order of nature: and those are simple natures, and their essences, and their notions. But all these things are both incorporeal and universal through what has been said before. And Aristotle found this subtlety, and therefore in all the things which he said, he is to be preferred to Plato in the positing of principles. This is the true determination of this question according to the Peripatetics; and thus it must be held, nor should care be taken over certain sophistical men who wrote certain things before us.