Cursus Philosophicus Thomisticus, Secunda Pars Artis Logicae

Around prior knowledge, the Philosopher lays down four points. First, as the foundation and root of the others, that every intellectual learning proceeds from prior cognition. It is called intellectual to distinguish it from sensory cognition; not every sensory cognition proceeds from prior cognition, for then the process would continue to infinity. Rather, it stops at the cognition of the external senses, which does not arise from some prior cognition.

Second, the things that must be presupposed before every learning and teaching are three: the subject, the attribute, and the premises or principles. For demonstration is constructed from these: we demonstrate an attribute of a subject through certain principles that are better known. Prior knowledge—that is, what must be known beforehand about such preknown things—is twofold: whether something exists and what it is. But because principles are complex and not simple, one does not know beforehand of them whether they exist or what they are, but that they are true. For the principles of demonstration must be true, since they not only infer but also establish the truth of its conclusion.

Third, there is an order among prior cognitions—not on the side of the subject and attribute, but on the side of the principles or premises, because the major premise can be known earlier in time than the conclusion, while the minor is known at the same time as it.

Fourth, a conclusion cannot be known beforehand formally, since it is demonstrated; it can be known only virtually, because the premises are known beforehand, and the conclusion is contained in them virtually.

We need not dispute here the last two points. The fourth presents no difficulty, and we shall discuss the third in article 3. Therefore, only the first two points remain to be explained.

Concerning the first, two things should be observed. FIRST: Authors disagree about what is meant by “intellectual teaching and learning”—whether it refers to every kind of cognition without qualification, or only to discursive or scientific cognition. One might understand that every intellectual cognition arises from another, insofar as the second operation arises from the first and the first apprehension from sensory cognition. Yet that does not serve the Philosopher’s purpose. He speaks only of cognition that proves by rational and discursive means, whether scientifically or probabilistically, as the passage is understood by St. Thomas, 1. Poster., lect. 1.¹ “Teaching” is cognition itself insofar as it teaches and makes us know; “learning” is the reception of cognition from another.

The reason is that Aristotle’s sole purpose is to show how something can be newly known, or cognition acquired, without either an infinite regress in proofs or a circle in which one thing is proved through another and conversely. For this purpose it was relevant to speak only of cognition acquired through proof and inference: cognition that is proved and proving, inferred and inferring. A proving cognition need not itself arise from some earlier proving cognition, because a cognition can be self-evident and not derived from another proof. Every cognition that is proved or demonstrated, however, presupposes another prior cognition from which it is proved or demonstrated. Whether cognition in us must arise from another cognition—namely, sensory cognition—not because it proves or is proved but simply because it is intellectual, is not relevant here. This discussion is not about whether the intellect depends on sense, but whether learning and teaching depend on some prior cognition.

SECOND, observe that Aristotle proceeds in explaining the generation and acquisition of our knowledge in the same way as he does in the Physics concerning the generation of natural things. Just as he proves there, against certain philosophers, that forms do not preexist actually, hidden within matter, but are drawn out from matter’s potency and thus acquired anew, so knowledge is acquired in us concerning conclusions—not because the conclusions are presupposed as already known in act and are said to become newly known only by recollection, as Plato held, but because they are known virtually and potentially in the principles, while the conclusions are made actually known and proved from those very principles.

From this the basis of Aristotle’s proposition is clear: every teaching and learning proceeds from prior cognition. That is, every unknown conclusion is deduced from some better-known principle, in which that conclusion is unknown in act but known virtually and potentially—just as things are generated in act not from nothing but from something in which they are contained potentially, namely matter. The Philosopher, then, speaks of knowledge acquired in the human way through principles and inference, which pertains to discourse.

Concerning the second point, carefully distinguish the grounds from which it follows both that something must be known beforehand for us to acquire knowledge and that there should be only three preknown things and two kinds of prior knowledge. The necessity of knowing or presupposing something beforehand arises from the principle that there can be neither an infinite regress nor a circle in demonstrations. It necessarily follows that we must stop at some cognition that is not proved through another; and, consequently, that cognition is presupposed or known beforehand in order to prove or demonstrate other things, but is not itself proved or known through another.

That the preknown things are three follows from the very object that can be demonstrated: a conclusion in which a proper attribute is predicated of a subject and demonstrated to belong to it. Aristotle therefore assigns preknown things only for demonstration, although they can readily be adapted proportionally to nondemonstrative syllogisms. Thus St. Thomas gathers these preknown things in 1. Poster., lect. 2.²: “We must know,” he says, “that what is sought to be known through demonstration is some conclusion in which a proper attribute is predicated of a subject, and this conclusion is inferred from certain principles. Since cognition of simples precedes cognition of composites, before one has cognition of a conclusion one must know in some way both the subject and the attribute. Likewise, one must know the principle from which the conclusion is inferred, since the conclusion becomes known through cognition of the principle. There are two modes of prior knowledge for these three things—the attribute, the subject, and the principle—namely, whether they exist and what they are. But it was shown in 7. Metaph.³ that complexes are not defined: there is no definition of a white man, and much less of any proposition. Since a principle is a proposition, then, one cannot know beforehand of it whether it exists, but only whether it is true. One can know what an attribute is, but since its quiddity depends on the subject in which it exists, one knows the attribute through demonstration as an inferred conclusion, while one knows beforehand what it is only as to the signification of its name; for one cannot know whether something exists unless one knows what its name signifies. A conclusion does not show what its subject is, much less whether it exists. One must therefore know beforehand of the subject what it is and whether it exists, since its definition supplies the principle for demonstrating that the attribute belongs to it.” Thus far St. Thomas.

From this teaching one can clearly infer the number of preknown things and what must be known beforehand about each. This is derived from a single principle: to infer a conclusion from principles, those principles must be presupposed before the demonstration—that is, known beforehand. Principles are propositions composed of terms; therefore, the terms themselves must all the more be known beforehand. There are three terms that concur in a demonstration: the subject and attribute in the conclusion, where they are joined to one another; and the subject and attribute in the premises, where they are joined in the middle term. By the force of that middle term, they are inferred as connected to one another. The middle term is the very quiddity of the subject, because every necessary connection among attributes arises from the necessary connection of quiddative predicates.

Therefore, only the subject and attribute need to be known beforehand insofar as they are presupposed in the premises and later joined in the conclusion. The same applies to the principles themselves, which contain the quiddity or definition of something; consequently, what is known beforehand in them is the middle term, namely the essential predicate in the definition, by reason of which the proper attribute belongs to the subject. It follows that what is known beforehand about the principles themselves is that they are true, since they are propositions.

What must be known beforehand about the subject itself is what it is, because the subject’s quiddity is not demonstrated but is the basis from which demonstration proceeds, and so is presupposed. A fortiori, one knows beforehand of the subject whether it exists, since the question whether it exists is presupposed to the question what it is. One cannot know what something is unless one presupposes that it exists. By “whether it exists,” we mean not merely its actual existence, which accrues contingently to its quiddity, but also its possibility—that is, whether something can be given in its genus, either in reality or in reason. In a word, the question whether it exists asks about the thing, not its cause: whether the thing exists or is given, but not why it is given. It asks whether the thing exists not according to contingent and accidental existence—which does not block the way to knowing what it is—but according to its proper concept, as Cajetan rightly notes in 2. Poster., cap. 7: whether it can be given.

Finally, we cannot know beforehand of an attribute what it is or whether it is such an attribute, because both are concluded through demonstration, which shows that the attribute belongs to the subject and, consequently, is found in and possessed by it—its existence—and depends on the subject in its intrinsic account—its quiddity. It remains, then, that we know beforehand only what the name signifies, because this cannot be demonstrated.

ARGUMENTS ARE SOLVED.

Against the first point, one may argue that Aristotle’s proposition, “Every teaching and learning, etc.,” either applies universally to every cognition or only to discursive and probative cognition. If the first, consider the cognition of angels, whose most perfect knowledge does not arise from prior cognition but apprehends principles and conclusions in a single intuition. Consider also our own case: since there can be no infinite regress, we must arrive at some cognition that does not arise from another prior cognition. If the second, the Philosopher’s proposition is not true, because discourse includes not only the conclusion but also the premises; therefore such discursive cognition does not arise from prior cognition but from itself, insofar as the conclusion is deduced from the premises it includes.

This is confirmed because the proposition does not answer Plato’s argument that we learn nothing new. Either we know what we seek, Plato argued, or we are ignorant of it. If we know it, then we already know it; if we are ignorant of it, even if it comes before us, we will not find it—just as someone will not find a person unknown to him. The same argument holds if every teaching proceeds from prior cognition: no matter how much prior cognition I have, if it does not show me what I seek, I will never find it; if it does show me, there is no further need to seek.

I ANSWER from what has been said: the Philosopher’s proposition is understood of cognition obtained through some proof, since this is properly teaching and learning: what we intend to learn is what we acquire through proof. What is not proved through another but apprehended immediately in itself is not learned and is not an object of learning. Thus there is no objection from the angel, who sees without proof the thing proved and without inference or discourse the thing inferred. Nor is there an infinite regress: we stop at a proving cognition that is not proved from another prior cognition, as with first principles, although ultimately this is resolved into cognition of the senses.

As for the claim about discourse, the answer is that if “discourse” is taken adequately to include both premises and conclusion, then it is true that discourse proceeds from prior cognition: from cognition of the principles in themselves, as grasped precisely through the habit of principles, we proceed to cognition of them as inferring, and consequently to the conclusion. If, however, discourse is not taken so adequately but as the cognition proved through discourse—which is the conclusion, and the only thing to which teaching and learning properly belong—then that cognition proceeds from prior cognition, namely, from the cognition of the premises that proves it. We might say, then, that every teaching—that is, every cognition proved through discourse, or discursive insofar as it is proved—proceeds from prior proving cognition.

The reply to the confirmation is that the Philosopher’s proposition answers Plato’s argument. If every learning proceeds from prior cognition, the conclusion is known virtually and generally in that prior cognition, insofar as it is contained in the premises, but is unknown formally and particularly. Thus cognition of it in potency gives rise to cognition of it in act; actual knowledge of it is not presupposed, as Plato held.

Second, one may argue against the second point, both against the number of preknown things and against the distribution of kinds of prior knowledge.

Against their number: the goodness of the inference to the conclusion must also be known beforehand, but the Philosopher does not list it here. Further, the middle term is known before the conclusion, since the conclusion is inferred by its force; therefore not only the subject and attribute should be known beforehand.

Against the distribution of prior knowledge: sometimes we inquire about the subject itself, whether it exists and what it is, in a given science—as when we inquire in theology whether God exists, and in physics whether motion or generation exists, and so on. And when something is defined, there is often controversy over whether it is defined well or badly, all of which is settled through science and discourse. Therefore we do not know the subject beforehand in the way Aristotle asserts.

Moreover, that “whether it exists” which is presupposed concerning the subject and attribute must refer either to existence or to truth. It cannot refer to truth, because then one would know beforehand of the subject the same thing as of principles: that it is true. But it cannot refer to existence either, because existence is not required for the subject to be knowable, since the object of science abstracts from existence. If one says that the existence presupposed is possible existence, there are two objections: first, science is given even of a being of reason—namely, Logic—and yet its possibility is not presupposed, since it is not a possible being; second, possible being is the same as not being fictitious, but true; thus what is presupposed would be whether it is true, not whether it exists.

Finally, it is wrong to say that only the name of an attribute is presupposed, for one also presupposes whether the attribute exists. Further, one cannot presuppose what a name signifies unless one presupposes whether the attribute signified by the name exists. Further, from the fact that an attribute belongs to some account, one infers that it belongs to the subject, as when we say: “Everything rational is capable of laughter; every human being is rational; therefore every human being is capable of laughter.” Here “capable of laughter” is posited in the premises as belonging to the rational, and from that one infers that it belongs to the human being. Therefore, one presupposes in the premises whether the attribute exists—and indeed also what it is, namely, that it belongs to what it flows from and to which it belongs per se. So of the attribute one does not presuppose only what its name signifies. Nor do we prove an attribute through the signification of its name, but through its fittingness to the subject; what is presupposed about the attribute is that through which it is proved.

I ANSWER the first part of the argument: Aristotle does not count the goodness of the inference among the preknown things because it is not a posterioristic preknown thing but a prioristic one, which he had treated in the books of Prior Analytics. As for the middle term, it is indeed known beforehand, but not separately from the principles, because the principles must be formed from the middle term so as to infer the conclusion. The subject and attribute, however, are known beforehand separately from the principles, because they belong to the conclusion as its matter, of which the conclusion is composed; they are not found precisely in the principles as the middle term is.

To the second part of the argument, the answer is that one always presupposes whether the subject exists in the science that treats it as its proper and adequate subject, in such a way that this is not proved through an intrinsic middle term. Yet one can sometimes prove in a science whether some subject exists and what it is, not through an intrinsic and a priori middle term, but either a posteriori or from principles borrowed from another science rather than from its own, or because that science is subalternated to another and proves its principles through it. Thus theology proves that God exists by borrowing arguments from Metaphysics; and Logic likewise proves from Metaphysics that a being of reason is given. The physicist, however, does not prove that motion in general, or mobile being, is given, since that is the adequate subject; he can prove that generation is given, which is an inadequate and partial subject.

To the third part of the argument, the answer is that the question whether something exists does not refer to existence but to possibility. A being of reason, too, has its possibility—not in order to exist, but to be cognized. The possibility of a thing is not presupposed as a formal and complex truth in the manner of an assertoric statement, as is presupposed of principles; rather, it pertains to transcendental and subjective truth. Possibility is said to pertain to the question whether something exists when it is considered not in signate act, as a quiddative predicate of essence distinguishing it from an impossible or fictitious being and expressing the causes of such possibility, but insofar as it simply exercises an order toward existence, which is extrinsic to quiddity, without considering the causes of such possibility.

Finally, to the last argument, the answer is that some hold that one knows beforehand whether an attribute exists because the attribute’s being follows on the being of the subject. But since that being follows through some middle term, by reason of which the attribute belongs to the subject and is proved of it, it is not presupposed but demonstrated. Therefore, when one knows what the name signifies, one does not know whether the thing signified exists, but only whether it exists in signification—or, rather, in the being of what is signified. Likewise, since an attribute is an accident whose being is understood through its order to a subject, even if in the premises it is understood to belong to some middle term, by reason of which it belongs to and is convertible with the subject, it is not yet understood formally and explicitly in relation to the subject, but only virtually, insofar as it is contained in that middle term. Therefore it is not presupposed as to whether it exists, but is proved, since the attribute’s being is understood through its order to the subject and its fittingness to it, even if it belongs to the subject through some middle term. If whether it exists is not presupposed, much less is what it is. The attribute is not inferred to belong to the subject from the signification of its name alone, though that signification is known beforehand, but from its connection with the middle term, which is also known beforehand in the principles.

Premises can be taken either formally or objectively. Formally, they are the acts of assent of the intellect itself by which we judge the propositions; objectively, they are the things themselves attained by assent and proposition. Logic arranges the objects themselves with respect to the connection they have, either as predicate and subject or as inferent and inferred, and presents them to the intellect, because it deals with things already known. The whole difficulty lies in arranging and attaining those things, not in really producing and ordering the cognitions themselves. Speaking in this sense, the Philosopher said in Physics II,¹ lecture 5 in St. Thomas,² that the premises contribute materially to the conclusion—that is, they provide the matter out of which it is made, because the terms of which the conclusion consists must already be had in the premises.

Now, therefore, THE ENTIRE DIFFICULTY concerns the formal premises themselves, that is, the assents to the premises: do they contribute in some kind of cause to the assent and inference of the conclusion? A similar difficulty often arises about how one act of the will is the cause of another, as intention is of choice; see I-II, qq. 9 and 12.

It is agreed by all that there is some dependence and connection between assent to the premises and assent to the conclusion, since the Philosopher says that all teaching and learning arise from pre-existing cognition—that is, a conclusion proved from a cognition that proves it. The intellect is moved from assent to the premises to assent to the conclusion, just as it moves from willing the end to willing the means.

It is also clear that final and material causes have no place in these assents. For even if the object or truth about which assent to the premises is concerned were the end, or provided matter, for the object of the conclusion, the act that concerns the object of the premises is neither the end nor the matter of the act or formal assent that concerns the conclusion, just as the act of intending is not the end of the act of choosing.

As for formal and efficient causation, some hold that the premises contribute as an extrinsic formal cause, as though specifying the conclusion, because the entire specification of assent to the conclusion is taken from the middle term of the demonstration; and when the intellect presents the premises, it properly acts only by specifying and determining. The foundation of this opinion is that it is not clear how one act of the intellect could cause another unless it left behind some determination by which the power proceeds to another act. On this view, the act itself does not contribute efficiently; rather, it is the power determined and applied by the act that does so.

HOWEVER, THE COMMON OPINION assigns efficient causation to the acts of the premises with respect to the act of the conclusion.

This is drawn from St. Thomas. In Posterior Analytics I, lecture 3,³ he says that the premises have the character of an efficient and active cause with respect to the conclusion. In Physics II, lecture 5,⁴ and Metaphysics V, lecture 3,⁵ he says that “as regards the power of inference, the premises have the character of an efficient cause.” Finally, in Summa theologiae I, q. 14, a. 7, he teaches that the reasoning by which we arrive at conclusions through principles is reasoning according to causality.

The FOUNDATION of this opinion follows from this: if the principles are related to the conclusion through reasoning according to causality, they must influence assent to the conclusion, insofar as the light of the premises so affects and determines the intellect that it manifests the conclusion to it and makes it assent by illuminating it. External light, present in a luminous body and diffused through a medium, causes the illumination of an object and efficiently determines us to its cognition. Therefore the premises, which cause the conclusion through reasoning by illuminating it as an external medium to the conclusion, efficiently influence assent to the conclusion.

Nor can one say that reasoning resembles motion, in which we pass from one thing to another, though one part of the motion does not produce another; so too, we pass from premises to conclusions as from one part of a motion to another, not as from an efficient cause to its effect. Some have thus said that assent to the premises stands as a starting point with respect to the conclusions. But this fails to distinguish reasoning according to succession from reasoning according to causality. Reasoning according to causality does not signify merely the succession of one cognition after another, as the parts of a motion are related; it also signifies the character of what illuminates, insofar as one proceeds from what is better known to what is less known. Consequently the premises determine the intellect by illuminating for it the manifestation of the inferred conclusion. They therefore cannot stand like a part of a motion that is left behind so that another part can be acquired, as a starting point stands in relation to an endpoint. Rather, this reasoning posits an inferential and manifestative power of the conclusion. Thus, insofar as they infer, the premises are not left behind by the intellect so that it may acquire the conclusion, as a starting point is left behind so that another may be reached. The premises themselves give the intellect a power—that is, a light—to acquire the conclusion; a place that is left behind does not give the motive power for reaching another place.

Nor can one say that assent to the premises influences the conclusions as a formal cause—not as their intrinsic form, but as an extrinsic form determining the intellect to the conclusions. Against this, an extrinsic form is either an object or an exemplary idea. Assent to the premises is not an idea of the conclusion, since the conclusion is not formed after their likeness, even though it is deduced from them through an intrinsic connection. Rather, assent to one premise leads the intellect to assent to another by manifesting it, not through imitation. Moreover, an idea needs the efficacy of a will that moves it in order to carry out its formation, since it causes in a practical mode. The premises, however, influence the conclusion in a purely speculative mode, without the influence of the will; the intellect is said to be moved to conclusions by the force of the premises, not by the will. But the intellect moves itself efficiently from one thing to another; therefore that moving force is efficient as well. Much less is assent to the premises an objective cause of the conclusions, since the conclusion has its own object, distinct from the premises and their assent, by which it is specified—namely, the truth that is inferred.

Whether the premises must actually exist together when the conclusion is inferred will be discussed in the following article. There, from St. Thomas, Posterior Analytics I, lecture 2,⁶ we shall show that in a demonstration the minor premise exists at the same instant as the conclusion, while assent to the major premise may precede it in time.

THE ARGUMENTS ARE ANSWERED.

First, it is argued: The whole efficient power of any cognition belongs only to the faculty, a habit added to it, or a species. One act is not operative of another act, although it can determine the faculty to another act. But assent to the premises is neither a faculty nor a habit nor a species, but an act of the intellect. Therefore it does not give the intellect efficient power to influence the conclusion.

It is confirmed as follows: the principles have the character of an extrinsic formal cause from which the specification of a science is taken. A different formal character of science is taken from a different middle term that proves or demonstrates, as St. Thomas affirms in II-II, q. 1, a. 1. Therefore the premises, which determine the intellect by means of the middle term that proves and illuminates the conclusions, function as their extrinsic formal account.

THE REPLY is that, although the intellect is the principal, universal efficient cause of assent to the conclusion, because the intellect proceeds inferentially from one thing to another it derives this inferential power from assent to the premises, in which the conclusion is virtually contained as something manifestable in what manifests it. When it is said that one act is not operative of another, a distinction must be made. If one act virtually contains another, it can produce that act by determining the faculty and giving it the power to move itself from one thing to another; but it cannot do so if it does not virtually contain the other act. We see this in the will: an act of intention causes an act of choice, and an act of command has the commanded act as its effect. St. Thomas also lists peace and joy among the effects of charity, in II-II, qq. 28 and 29, and joy as an effect of devotion, in II-II, q. 82, a. 4. For this reason an act of a virtue is distinguished from its effect: the act is elicited immediately, while the effect is commanded through another act. One act is said to determine and move to another insofar as the prior act concerns an object under which the object of the other act is virtually contained. Thus, by the very fact that the power is ordered by such an act to an object, the act has within itself the power to determine the faculty to an object contained under that one. And through this ordering or determination left by such an act—whether it is left by some impressed mode or by some species representing the past act—the faculty is moved and determined to proceed to another act.

In reply to the confirmation, the premises provide the specifying middle term if they are taken on the side of the object known, since the object specifies and formalizes the act. But on the side of the assent by which that object is known, there is no contradiction in its efficiently influencing the faculty by ordering it to the eliciting of another act and, as an interior light, formally illuminating it—that is, by inhering within it, not objectively.

Second, it is argued: If the premises efficiently influence the conclusion, it follows that assent to the premises must exist at the same time as assent to the conclusion is elicited, since an efficient cause influences only while existing. But this is false, because cognition of the premises passes away when the conclusion arrives: through reasoning and movement we pass from one thing to another, and the intellect cannot understand many things at once, as St. Thomas teaches in Summa theologiae I, q. 85, a. 4. It further follows that the minor cannot be known at the same time as the conclusion, contrary to what the Philosopher teaches in Posterior Analytics I, chapter 1,⁷ and St. Thomas there, lecture 2,⁸ since two cognitions cannot occur together, for we cannot understand many things as many. But if there is not a double cognition, neither is one efficient in another. Then at least one premise, namely the minor, does not influence the conclusion efficiently. The major alone, without the minor, cannot efficiently influence the conclusion, because the arrangement of the premises is not present in the major alone.

The second difficulty is that if the principles are the efficient cause of the conclusion, they cannot be its univocal cause, since assent to principles is of a different species from assent to conclusions, as arising from habits of different species. Therefore they will be an equivocal cause with respect to the conclusion. This cannot stand, because an equivocal cause is not proximate and immediate but universal; yet nothing intervenes between the premises and the conclusions.

Finally, if the premises are an efficient cause, God could supply their efficiency in producing the conclusion, and thus a conclusion would be inferred without the premises, which is impossible.

THE REPLY to the first difficulty is that the influencing cause exists when the conclusion is inferred, because the minor and the conclusion are known at the same time, although the minor is prior by nature, as St. Thomas teaches from the Philosopher in Posterior Analytics I, lecture 2,⁹ This is understood of the minor insofar as it virtually contains within itself the major, which it determines; this will be discussed in the following article. Nor does reasoning require that one act pass after another in temporal succession, but rather in the succession or causality of cognitions and objects, although both cognitions endure at the same time. If, however, the inferring cognition does not remain in act, it will remain virtually, in the determination by which it determines the intellect to infer the conclusion. Nor does St. Thomas deny that many things can be known at once with temporal simultaneity; he denies that they can be known with simultaneity of cognition and representation when they are not ordered or united under some aspect, but are disjoined and separate from one another. Thus, although the minor and conclusion are known at the same time, the minor can nevertheless be the efficient cause of the conclusion, because it is prior by nature though simultaneous in time, and is a distinct act.

To the second difficulty it is said that the premises are the efficient cause of the conclusion by way of a power and an instrument. An equivocal instrumental power can be immediate and proximate with respect to its effect, just as heat in an animal generates flesh, and light generates heat, immediately and proximately. As for how these assents or acts attain the conclusion by some action, about which some have doubts, the reply is that they do not attain it by any transient action, but by the very immanent action through which the conclusion proceeds from the intellect. It also proceeds efficiently from the habit as assisting, and from the actual assent to the premises as from a light that presently illuminates and provides the faculty with efficient and determining power.

To the final difficulty it is said that not every efficiency can be supplied by God in every mode—namely, when the efficiency imports or connotes some special mode or dependence under which God cannot act. Thus God can produce a human being, but cannot generate bodily as a father; and he can concur in reasoning, but cannot reason. Similarly, he cannot produce a conclusion as inferred without the premises.

Here we are speaking of premises in a demonstrative syllogism that convinces the intellect and necessitates it by the granting of the premises.

But in a probable syllogism, once the premises are granted and the validity of the inference stands, is the intellect necessitated to assent to the conclusion? I answer briefly: it necessitates the intellect by the force of the inference, not by the force of the truth of what is inferred. Therefore it does not necessitate it absolutely. For although, once the premises are granted and rightly arranged, the intellect cannot dissent if it proceeds to the conclusion, in probable matter it can refrain from proceeding to the conclusion and instead go back to examine the premises; since they are probable, it can dissent from them. This does not apply in demonstration, in which the intellect must not only proceed to the conclusion but also cannot go back. Thus St. Thomas teaches in Summa theologiae I, q. 82, art. 2, that the intellect does not assent necessarily to contingent propositions whose removal does not entail the removal of their principles. Therefore, since even with the premises posited the intellect sees that removing them does not remove the prior principles, it can go back from the premises and thus is not necessitated absolutely. It is nevertheless bound to assent to the probability itself, if it is evident, though not to its truth.

Thus, for the POINT OF THE PRESENT DIFFICULTY to become clear, we must assume the familiar distinction between necessity with respect to specification and necessity with respect to exercise. The first concerns the species of the act, the second its eliciting. The first is therefore explained conditionally: if the power elicits an act, it can elicit only an act of that species; yet it can absolutely refrain from eliciting one. The second, by contrast, is explained absolutely, because in fact the power is bound to elicit the act. A twofold freedom corresponds to this twofold necessity: one with respect to specification, also called freedom of contrariety, because it can concern specifically contrary acts, for example, hatred and love; the other with respect to exercise, called freedom of contradiction, which concerns only eliciting or not eliciting an act.

When we ask here whether the intellect is necessitated to assent to the conclusion, we are speaking of formal, not virtual, assent. Virtual assent is present in the premises, in which the conclusion is virtually contained; thus virtual assent to the conclusion is the same as formal assent to the principles as disposing us toward it.

In the present case, then, it is beyond dispute that, when evident premises stand, the intellect is necessitated with respect to specification to assent to the conclusion. The reason is that there can be no dissent concerning the true as true, nor assent concerning the false; otherwise someone could assent to two contradictories, if one could assent to or dissent from truth equally, and likewise in the case of falsity. But when true and evident premises are posited, the conclusion cannot fail to be true; otherwise a true antecedent could have a false consequent. Therefore such a conclusion is no more capable of dissent than of falsity; consequently, it necessitates assent. The difficulty that remains, then, concerns necessity with respect to exercise.

In this regard, some think that, when the premises are posited, the intellect is not necessitated with respect to exercise concerning such a conclusion, but can be impeded by the will. This can be explained in two ways: first, the will could directly suspend the intellect so that it does not proceed to assent to the conclusion, just as it suspends the hand from moving; second, it could do so indirectly by diverting the intellect to another cognition or preventing it from attending to the premises. Others teach without qualification that, once assent to the premises stands, the intellect is necessitated with respect to exercise.

NEVERTHELESS, LET THERE BE ONE CONCLUSION: When evident premises stand, the intellect is directly necessitated with respect to exercise to assent to the conclusion. The will can, however, impede it indirectly, because the intellect is not necessitated to attend to and consider the premises.

This is the common view and is drawn from St. Thomas, Summa theologiae I, q. 82, art. 2, where he says that the intellect naturally adheres by necessity to principles and conclusions having a necessary connection with them. He teaches this more clearly in Summa theologiae I–II, q. 17, art. 6, where he says: “An act of reason can be considered in two ways. In one way, with respect to the exercise of the act, as when someone is commanded to attend and use reason; in this way an act of reason can be commanded. In another way, with respect to the object, in relation to which two acts of reason are considered. First, reason apprehends the truth about something; this is not in our power, for it occurs through the power of some light, natural or supernatural. Therefore, in this respect, the act of reason is not in our power. Another act of reason occurs when it assents to what it apprehends. If, then, what is apprehended is such that the intellect naturally assents to it, as with first principles, assent or dissent concerning such things is not in our power but is subject to the order of nature. There are, however, some things apprehended that do not so convince the intellect that it cannot assent or dissent, or at least suspend assent and dissent for some reason; in such cases assent or dissent itself is in our power.” Thus St. Thomas. Here he distinguishes two kinds of exercise: one concerning the application of attention to this or that object, and another concerning the application of assent. The first application lies in the will's power, so that it can attend to or think about the premises; the second application, with respect to assent itself, is not in the will's power except with respect to objects that do not convince the intellect. Therefore, with respect to objects that convince and necessitate the intellect, it cannot do this—not only cannot it dissent or assent at will, which is freedom of contrariety, but it cannot suspend or refrain from suspending assent, which is necessity of exercise, since St. Thomas says that in this respect it is not in our power; the exercise of an act, however, is what depends on our power.

From this it follows that the will cannot directly impede the exercise of assent to an evident conclusion once assent to the premises is posited. For the will cannot impede the vision of an object when the light illuminating it and the eyes open are posited, as experience itself makes clear and reason plainly proves: in that case all the causes are natural agents that cannot be impeded by the will. For the light itself naturally manifests and illuminates the object, while the cognitive power naturally operates in cognizing an object sufficiently presented. It is clear that evident premises, rightly arranged, illuminate and manifest the conclusion as light does colors. The intellect itself is also a non-free power, operating naturally with respect to an object sufficiently presented, that is, illuminated. Therefore, when such illumination stands and the power itself is awake and attending, it necessitates with respect to exercise and cannot be impeded by the will, just as the will cannot keep open eyes from seeing.

The will can, however, divert the intellect indirectly from assent to the conclusion, because it can divert the intellect from thinking about the premises, just as one can turn away from or close one's eyes to something plainly visible. If assent to the premises is relaxed or omitted, or one does not consider how they are arranged for inferring the conclusion, illumination concerning the conclusion does not follow.

From what has been said you will understand how the Philosopher's statement here is to be understood: “The major is known earlier in time than the conclusion, but the minor is known at the same time as the conclusion.” He is speaking of the major considered in itself and separately. Since it is the more universal proposition and is not subsumed under another but is itself assumed, it can be known separately and by itself, and therefore earlier in time. But if the minor is considered formally as a minor, that is, as inferior and subsumed under the major and determining it to influence the conclusion determinately, it cannot be understood unless the conclusion is understood at the same time, provided that it is subsumed and arranged under the major. This is understood not only negatively—that nothing intervenes between the cognition of the minor and of the conclusion—for that is evident, since the minor is the last part among the premises and so the immediate part joined to it must be the inferred conclusion, which is something outside the premises. Rather, it is understood positively as well: in the same instant that the minor is cognized as minor, assent to the conclusion is deduced, as St. Thomas asserts in his commentary on Posterior Analytics I, lect. 2¹. For once cognition of the minor is posited formally as coordinated and subordinated to the major, and thus the validity of the inference is presupposed as known, a sufficient and necessitating light for manifesting the conclusion is thereby posited. The conclusion is manifested by no other light than the inferential light contained in the premises. Illumination takes place in an instant—much more so in the case of spiritual light than corporeal light, because spiritual light is more effective and perfect and less dependent on the body. Therefore, in the same instant that the light of the premises is posited, ultimately determined by the minor, assent to the conclusion is posited as proceeding from a cause that is unimpeded and acts instantaneously, just as was said of illumination.

You will say: The intellect is a limited power and cannot elicit several acts at the same time, or at least can elicit only a definite and limited number. Therefore, it could be that assenting to the minor is the last act the intellect can elicit by its natural power; consequently, it could not then elicit assent to the conclusion.

The reply is that in such a case, if the intellect cannot relax any of its preceding cognitions, either because they necessitate the intellect or because the will does not wish it to withdraw from them, the intellect will not produce formal assent to the conclusion because of the impediment and limitation of its power. Here, however, we are speaking of an unimpeded cause. This is compatible with the intellect being necessitated simply by the light of the premises, just as fire necessitates heating and the eye necessitates seeing, provided there is no impediment and its power does not exceed its capacity to act.

As for what some further think, in a stricter sense, namely, that the minor and conclusion can be cognized not only simultaneously but also in one indivisible cognition of principle and conclusion, this is proper only to angelic light, which by one act accomplishes all that our discursive reasoning accomplishes through many acts. By discursive light this cannot happen; a human being would have to be raised divinely above the connatural mode of human cognition, as is usually admitted in the case of Christ's infused knowledge. If, however, we speak of virtual cognition of the conclusion, it is clear that it is cognized in the premises by the same act as the premises.

THE ARGUMENTS ARE ANSWERED.

First it is argued: The will is not necessitated by some particular good that does not pertain to its proper being. But assent to the conclusion, even after assent to the premises, is a particular good, according to St. Thomas's rule in Summa theologiae I–II, q. 9, art. 1, ad 3, that the very truth which is the intellect's perfection is contained under the universal good as a particular good. Therefore, the will is not necessitated by it with respect to exercise.

It is confirmed: If the will necessitates assent to an evident speculative conclusion, it also necessitates assent to an evident practical conclusion, such as: “Do not do to another what you would not want done to yourself; but you do not want to be robbed; therefore you ought not to rob another.” Yet the will is not necessitated to assent to this practical conclusion, since it sometimes does the opposite. Therefore, and so on.

THE REPLY follows the teaching given above from St. Thomas concerning the two kinds of exercise: to apprehend principles, to assent to them, or to assent to conclusions necessarily deduced from them. With respect to the first, the will is free and can draw the intellect back so that it does not think about the principles; thus it can indirectly cease from assent to the conclusion and fail to continue it by introducing an impediment. The will cannot impede the second kind of exercise, once assent to the premises is supposed, in propositions that convince the intellect, as we showed above from St. Thomas.

To the confirmation, the reply is that a practical syllogism, insofar as it is practical and effectively moves the will with respect to exercise, does not necessitate the will. First, because the will can divert the intellect's cognition from the right proposition of the principles, just as it can in speculative matters, in accord with Psalm 9²: “Your judgments are removed from his sight.” If it does not divert the intellect from the right proposition of the principles, it will be necessitated to the practical conclusion by supposition and in a qualified sense. Second, because correctly arranged practical principles necessarily conclude only that something is due to be done, or is fitting according to law—not always that it is appetible. In exercise, appetibility is proposed with indifference unless God is clearly seen. In this respect, therefore, a practical syllogism does not conclude by compelling assent but by proposing indifferently; the will follows the appetibility that is proposed here and now, not merely what is fitting to reason according to law.

Second it is argued, that even once assent to the premises is posited, the intellect needs a habit in order to assent to a scientific conclusion, since science concerns that conclusion. Therefore the intellect retains some indifference toward such assent even when the premises are posited. For if it had none, it would generate no habit: where there is total determination of a power, no habit that removes its indifference is given; but where there is some indifference, there is not complete necessity.

It is confirmed: If two conclusions are inferred from necessary premises, one direct and the other indirect—as when Baralipton is inferred from premises in Barbara—the intellect would be necessitated to both conclusions. This is false, because one demonstration elicits and requires only one conclusion; therefore the will determines which one it will choose. Finally, if, once the premises are posited, the intellect is necessitated to exercise assent to the conclusion, by the same reasoning it will be necessitated to continue assenting while the same premises remain. Thus, once a demonstration has been made, it could not cease.

THE REPLY is that a scientific habit does not reach only the inferred conclusion, on the supposition of assent to the premises and the validity of the inference; it also reaches the premises as inferential and their arrangement. All of this requires a habit, so that a demonstration can be elicited not only when it is first made but also later. It is true, however, that if we attend only to the inference of the conclusion after assent to the premises and their correct arrangement, this alone would not require a habit overcoming some difficulty.

To the confirmation, the reply is that when two conclusions are inferred from the premises, they are not both inferred equally immediately; the indirect conclusion is inferred through some conversion or transformation of a proposition. Hence, just as the intellect is necessitated to assent to the first conclusion only when the premises are rightly arranged, not in any manner whatsoever, so it will not be necessitated to the indirect conclusion with equal immediacy, but only after the stated transformation or conversion has been made. As for continuation of assent, when assent to the premises is continued, assent to the conclusion will also continue; but the intellect can be diverted from thinking about the premises and thus cease assenting to the conclusion.

To explain fully what pertains to knowing the premises, we must set out their conditions, which premises serving demonstration must satisfy.

Thus, the first thing to consider is a proposition known per se, or immediate. For although not every demonstration is formed from propositions known per se, every demonstration nevertheless depends on them and is resolved into them. And since every proposition known per se is immediate, it is explained negatively insofar as it is immediate, and positively insofar as it is known per se. A proposition is defined as immediate by the Philosopher, as also by St. Thomas, Posterior Analytics I, lecture 5¹: “a proposition lacking a middle, or a proposition before which there is no other.” It is understood to lack a probative middle in an intrinsic and a priori proof, as will be explained further in the following disputation, although it can admit proof a posteriori and through extrinsic causes. Hence St. Thomas says, De Veritate, q. 10, a. 12², that something is known per se when the predicate is “of the account of the subject.” Here one must observe that this definition is to be understood formally: that is, when a predicate belongs to the account of the subject immediately and per se. Otherwise, if a predicate belongs to something through another, it is not incompatible with its being proved and made manifest through some middle, however essential it may be. Thus it can be proved that a human being is sentient because he is an animal, and that a line is not a substance because quantity is not a substance. The Philosopher mentions this in Posterior Analytics I, ch. 11³; St. Thomas may be consulted there, lecture 26⁴. And this is how the divine Thomas is to be understood in Summa theologiae I, q. 14, a. 1, when he proves that God is intelligent because he is immaterial: intellectuality is included in immateriality and converts with it, just as Peter is proved rational because he is a human being. These are proofs from what includes to what is included.

If, however, a proposition known per se is considered positively, it is defined as “one that becomes known from the terms themselves, or from an explanation of the terms.” Hence it is clear that a proposition known per se is not the same as one known intuitively or through sensory experience. For what is known by sense is not known as a proposition; nor does it become known either as a simple object apprehended or from the explanation of the terms alone, but because it is reached by external experience. Thus, although snow’s being white is known by experience in sense, in the intellect it is not a proposition known from terms connected per se, but rather concerns contingent matter. Finally, a proposition known per se is not the same as one known without reasoning. For through faith we know without reasoning, on account of the authority of the speaker, and yet this is not known per se; and an angel knows without reasoning in first principles things that become known through proof and causes.

We explained in the text, ch. 2, how a proposition known per se, or a first principle, is divided into axioms and propositions—that is, into most common and less common principles. It will be discussed further in the following disputation.

There is, moreover, the celebrated division of a proposition known per se into one known per se in itself and one known per se to us, which St. Thomas gives in Summa theologiae I, q. 2, a. 1, and De Veritate, q. 10, a. 12⁵. Scotus and his school generally do not accept it, however, and some more recent authors say that St. Thomas spoke improperly by dividing a proposition known per se in this way. For what is known per se in itself and not to us is, strictly and formally, not a proposition but the thing signified by the proposition. Yet this thing is not said to be known per se or knowable except insofar as it is subjected to terms, whether formal concepts or words, by which it is made known. If, then, the terms that make it known are not themselves known per se but are proved through something else, neither will the proposition itself be known per se as a proposition. But if the very thing signified is subjected to other terms known per se, it will be a proposition known per se—not, however, insofar as it is subjected to those confused terms that must be proved through something else. The whole opposing argument, which denies that there is a proposition known per se in itself, is reduced nearly to this.

Nevertheless, St. Thomas, considering a proposition known per se more deeply, spoke not only of it according to the formal signification of a proposition, on the side of the concept or word that signifies, but also on the side of the foundation found in the very thing signified. For whether a proposition is demonstrable through another middle or lacks the middle by which it is demonstrated, and is thus immediate and known per se, arises not from the signification of the terms themselves but from the very connection of the things signified. For where a predicate belongs immediately to a subject, it lacks a middle by which that predicate might be proved of that subject; consequently, so far as it itself is concerned, it grounds a proposition known per se. Yet a proposition known per se cannot always be formed with respect to us, because the extremes or terms of which that proposition consists are not immediately known to us, so that their connection with one another is evident to us through the explanation of the terms alone. Rather, it becomes known presupposing a reasoning process that makes the terms manifest and consequently their connection. Therefore it is not known per se to us absolutely, but presupposing a reasoning process; that is what it is for something to be known per se to the wise.

There is no impropriety in taking a proposition objectively, not formally, when we speak of a proposition, but from the side of the thing signified, which is formally signified through concepts and terms. St. Thomas did this all the more aptly because the present concern is more to explain the truth of a proposition than the proposition itself. For the subject is whether a truth is demonstrable or indemonstrable, that is, known per se; this had to be explained also from the side of its foundation and of the thing signified.

Hence the opposing argument is answered. We use “proposition known per se” not only for a formal proposition but also for its objective content and for the foundation of its truth. It is known in itself when, on the side of the object, it has an immediate connection; it is known per se to us when that connection is constituted and explained by such terms that the connection of the extremes becomes known without any reasoning, through the explanation of the terms alone.

Concerning the predicate of every, to understand what it is and how it is required for the premises of a demonstration, one must note, following St. Thomas, Posterior Analytics I, lecture 9⁶, that “being predicated of every” is taken one way in the books of the Prior Analytics and another way here. There, attention is given only to the form of universal predication of every subject; here, to its matter or necessity. Thus there the predicate is said to be of every subject when it belongs to each thing contained under the subject, whether necessarily or contingently. In a word, “being predicated of every” according to the Prior Analytics form means any predicate qualified by a mark of universality and distribution, whether probable or necessary; for syllogistic form does not consider this, since it serves demonstrative as well as opinionative syllogism. By contrast, the Posterior Analytics sense of “of every” includes two conditions, as St. Thomas says in the cited place. First, nothing can be subsumed under the subject to which the predicate does not belong; in this it agrees with “of every” in the Prior Analytics sense. Second, there must be no time at which the predicate does not belong to it. Thus the Philosopher designates certain and necessary truth, and embraces the whole definition in these words: “By ‘of every’ I mean that it belongs to one and does not belong to another, applies at one time and does not apply at another, but applies to every one and always.”

Accordingly, two kinds of universality are understood here: of time and of supposits. Universality of supposits is either positive or negative. Positive universality actually has several inferiors; negative universality is such that, in itself, it is not incompatible—or is not conceived as incompatible—with several things being taken under it, whether it has several in reality or is incompatible with having them, provided that its formal concept does not present it as incompatible. This second mode of universality suffices for demonstration concerning God and the angels, although in reality they have no multiple inferiors, because they can be conceived after the manner of a common thing, as was said above, q. 8⁷. It does not apply to a singular term, such as Peter or Socrates, because their very mode of being conceived expresses singularity, which is incompatible with universality.

Similarly, universality of time is spoken of in two ways: in one way, simply and absolutely. “Absolutely” means throughout every difference of time, or perpetually; “restrictedly” means what belongs to something given its existence, either continuously—as blackness to a raven—or at certain times—as flowering to a tree.

Concerning the predicate per se, one must note that, speaking generally, it is what is opposed to a predicate per accidens. “Per accidens” sometimes means not essentially but accidentally and contingently. Likewise, per se sometimes means immediately, or not through another; at other times it means necessarily and essentially.

The Philosopher divides the predicate per se into four modes of per se predication, which St. Thomas gathers in Posterior Analytics I, lecture 10⁸, because the particle “through” signifies two things: either a relation of cause or a relation of position. A predicate is said to be per se when it is without another, or alone. When “through” signifies a relation of cause, it can signify an intrinsic cause, such as a formal or material cause: for example, when a body is said to live through the soul as through its form, or to be colored through a surface as through its material cause. Or it designates an extrinsic cause, especially an efficient cause, as when water is said to be heated through fire.

The first mode of per se, then, occurs when something is attributed to something through its form. Since a definition is maximally formal in every thing, when a definition or some quidditative predicate belonging to the definition is predicated of something, it is said to be predicated in the first mode per se.

The second mode of per se, St. Thomas says, is taken when the preposition “through” designates a material cause, that is, the proper subject of some form, which belongs to the form’s definition. This is the same as saying that when a proper attribute is predicated of its subject, it is the second mode per se. For although the predicate is not of the essence of the subject, the subject nevertheless belongs to the essence of the predicate, insofar as the proper subject is placed in the definition of the attribute.

The third mode per se is not a mode of predicating but of existing: something is said to be per se, that is, alone, as primary substance is said to exist per se. Concrete accidents, such as white or musical, are not understood to exist alone, but with the form that denominates and inheres in another, namely, a subject.

Finally, the fourth mode of saying per se is not a mode of predicating or of being, but of causing. Aristotle defines it: “When something belongs because of itself”; that is, when the proper rationale by which it is caused is signified. For example, “A builder builds,” but not “A builder walks,” because the art of building does not contribute to walking. Thus, in this fourth mode of saying per se, there is, as it were, an appeal to the proper form and rationale for causing something: what contributes to causing is signified, not what does not contribute, even if the latter is found there identically and materially. Hence it can well be that something belongs in the first mode per se but not in the fourth. Essential identity suffices for it to belong in the first mode, whereas the fourth requires the formal relation under which something belongs or is caused. Thus animal and rational are identified, and belong to a human being in the first mode per se; yet “Animal reasons” is not per se in the fourth mode, because “animal” does not signify the formal rationale for reasoning.

From these points you will gather that a predicate per se in the first or second mode must be predicated of every subject, because it belongs necessarily, and hence always and to all. The third mode per se applies only to a singular; the fourth applies to singulars and universals alike wherever the formal rationale of causing is signified.

BUT YOU WILL OBJECT: This proposition, “The risible is a human being,” is not in the first mode, yet the predicate is part of the definition of the subject. Therefore Aristotle wrongly reduces to the first mode per se what is placed in the definition, and then to the second mode when the subject belongs to the definition of the predicate.

The same argument can be made about indirect predications, which are not “of every” and consequently are not per se, yet one thing can be placed in the definition of another. For example, when I say, “Animal is human or rational,” “animal” is placed in the definition of the predicate; and likewise when one correlate is defined through another. Therefore it is not right to say that the first mode per se occurs when a definition or part of a definition is predicated of something.

Third: All contingent predicates will be per se in the second mode, because the subject is placed in the definition of any accident, even the fifth predicable, as is gathered from St. Thomas, De ente et essentia⁹. Therefore the definition of the second mode per se is not sound.

Finally, contingent predicates are placed in the fourth mode, as when one says, “Fire heats,” or “A builder builds.” For actions that belong contingently to agent causes and can be impeded are predicated. Therefore they are not predicates per se, since what belongs contingently belongs per accidens.

The answer to the first objection is that authors are divided concerning the proposition in which the subject of an accident is predicated of the accident itself. Some think it is absolutely not per se in the first mode, because the subject is not an intrinsic part of the accident and the proposition itself is indirect, and consequently is neither “of every” nor per se; for example, “White is a body,” “The risible is a human being.” Thus Cajetan, Posterior Analytics II, ch. 18, judges absolutely that these are propositions per accidens, although they are improperly called per se. He thus explains his own position, having said in ch. 3 that this proposition was per se because the subject is part of the accident’s definition, whether in the direct or oblique case.

Others say that the subject is predicated per se in the first mode of the accident, not absolutely, but by addition and extrinsically, because the quiddity of such an accident depends on its subject as on something extrinsic. Thus it is predicated per se in the first mode in the way it belongs to the definition. Hence, among examples of the first mode per se, Aristotle places a triangle, which consists of lines, and a line, which consists of points. A point, however, is predicated of a line only obliquely, as the term of a relation and the object of a power. When Aristotle says that a subject is predicated per accidens of an accidental form, “per accidens” is understood to mean through another, not accidentally. Thus, when a snub nose is called a nose, “nose” belongs to it through another, namely, through the human being who is its subject. Or, better, Aristotle is not speaking of a proper subject: a foreign and common subject in relation to the accident makes the proposition accidental. This is certain from the Philosopher’s text, as is clear in this book I, ch. 22¹⁰, lecture 33 in St. Thomas¹¹, where Aristotle gives as an example the statement, “White is wood.” The case is not similar when a proper subject is predicated of its attribute because of the necessary connection between them. This last solution seems sufficiently probable, although the first is not without probability. The answer to the argument, then, is that Aristotle placed in the second mode per se those propositions in which the predicate is the proper attribute of its proper subject, because such a subject belongs to the account of the predicate. If, however, the subject to which the proper attribute belongs is predicated of the attribute itself, the Philosopher did not say that this belongs to the second mode.

The answer to the second objection is that indirect predications are not excluded from the second mode per se simply because they are indirect, as some think, on the ground that an indirect proposition is not “of every,” which is required for a proposition to be per se. An objection is raised, however, from those indirect propositions in which the subject converts with the predicate, so that the predicate belongs to every subject, as when one says, “The risible is a human being,” or “The rational is a human being.”

Therefore one must say that among these indirect propositions, some are essentially identical, as when one says, “The rational is a human being.” In that case the proposition also belongs to the first mode by identity, because one extreme belongs to the essence of the other by identity. At other times they make a contingent proposition, as when I say, “Animal is a human being”; then it is in no mode per se and is not “of every,” because it is contingent. At other times the subject is predicated of its proper attribute, as in “The risible is a human being”; then it is in the first mode per se, because the predicate “human being” belongs to the definition and quiddity of the risible, at least by addition, just as a proper subject is placed in the definition of an accident, as is said in Metaphysics VII¹². In the same way, when a correlate is predicated of its correlate in the oblique case, as when one says, “A father is the father of a son,” it also belongs to the first mode per se obliquely and by addition, because in this way it belongs to its definition. This proposition, however, “Animal is rational or irrational,” is necessary and “of every” by reason of the disjunction, and is reduced to the second mode per se. For although rational and irrational are contingent differences, that disjunct functions as a proper attribute, since it is proper and per se to animal to be contracted by one of that disjunction.

The answer to the third objection is that common accidents, if they can be reduced to a proper subject—heat to fire, cold to water, for example—are then defined as proper attributes through such subjects, in the first mode per se by addition, as explained. If, however, they cannot be reduced to some proper subject, then they are not defined through such a subject insofar as concerns the rationale of their species, because they do not derive their species from that subject. The inherence of such an accident, however, or the accident insofar as it is capable of inhering, is defined through the subject, because aptitude for inhering is essential to an accident, though it belongs to it generically, not specifically.

The answer to the fourth objection is that a predicate per se in the fourth mode can be accidental in its predication, but it is per se in causing. Thus, “What is hot heats” expresses predication of the fifth predicable in the order of being, but causality per se in causing.

Concerning the predicate called secundum quod ipsum or universal, one must note, following the divine Thomas, Posterior Analytics I, lecture 11¹³, that “universal predicate” is not said in the way the five predicables are called universals in predication, but according to a certain totality and adequacy: neither is the subject found without it, nor it without the subject. This is to say that they convert with one another. For something can be predicated universally but not secundum quod ipsum, as when one says, “Every stone is colored.” The predication is universal, but not secundum quod ipsum, because a stone is not colored insofar as it is a stone, but insofar as it is a mixed body.

Therefore three conditions are required for a universal predicate, or one secundum quod ipsum: First, that it be “of every.” Second, that it be per se in the first or second mode, that is, belong necessarily. Third, that it be said convertibly, or insofar as it is such. For this reason the ultimate difference and its proper attribute belong per se in the first mode and secundum quod ipsum. Thus “A human being is rational or risible” belongs per se in the first mode and by reason of the human being himself. If, however, one says, “A human being is an animal or sentient,” it does not belong per se in the first mode, although it belongs essentially, because it also belongs to others and consequently by reason of a common nature—not convertibly, but secundum quod ipsum.

This predicate is therefore defined as “what is predicated of every subject, per se, and as that which it itself is.” By per se, I mean in the first or second mode of per se predication, which alone are modes of predication. Thus “of every,” per se, and secundum quod ipsum stand as higher and lower: every predicate secundum quod ipsum is per se, but not conversely; every predicate per se is “of every,” but not conversely.