Scholastic Terms and Axioms
SCHOLASTIC TERMS AND AXIOMS
Like other philosophical systems, scholasticism has developed its own terminology. Some medieval scholastic expressions were simply Latin versions of Aristotle's dicta, e.g., abstrahentium non est mendacium and propter quod unumquodque tale et illud magis. Other axioms, such as actiones sunt suppositorum, came from the scholastics themselves. The majority of the resulting distinctions and principles stubbornly resist translation and have been left in their Latin original. However, since Latin has faded from the family of living languages, the need for translation and explanation is imperative if scholasticism is to exercise influence outside its rather limited circles.
In the following listing, terms and expressions have been grouped before axioms, and separate alphabetization has been used in each category.
Terms and Expressions
For the most part, the fundamental Aristotelian-Thomistic meanings are presented here. One must realize that even within scholasticism, many shades of meaning are attached to these terms. The present listing is neither extensive nor exhaustive, but is intended merely as a handy reference to the best known expressions.
Actu exercito (obliquely, indirectly ), actu signato (expressly, directly ). In general, something is done actu signato when it comes about through the direct, express intention of the one acting; on the other hand, when the agent only indirectly or obliquely intends the effect, then the result is said to be brought about actu exercito. This distinction has application in several diverse areas, and in each of these respective areas its meaning undergoes a different refinement. In logic, for example, it is used to clarify the way in which the human intellect forms a universal concept. The mind does not know "universality" as such and then attribute it to the concept that it has formed (actu signato ); rather, it recognizes the concept as pertaining to many individuals, and thus becomes aware of its universality indirectly (actu exercito ). In the moral order, a person is said to indicate his intention actu signato when he expressly manifests it in words, but actu exercito when he shows it equivalently by his deeds. This distinction thus underlies the popular adage, "Actions speak louder than words." (see act.)
Adequatio rei et intellectus (the adequation of the thing and the intellect ). In this way does St. thomasaquinas define truth, after giving definitions by Augustine, Hilary, and Anselm (cf. Summa theologiae 1a, 16.1). "When the mind is the rule or measure of things, truth consists in the equation of the thing to the mind just as the work of the artist is said to be true when it is in accordance with his art" (Summa theologiae 1a, 21.2). However, for the most part reality is the measure of the intellect, and truth consists in the mind's apprehending things as they are. Yet "truth principally is in the intellect, secondarily in things, insofar as things are compared in the intellect as to a principle" (Summa theologiae 1a, 16.1; cf. Aristotle Meta. 1027b 18–29).
A posteriori (from what comes afterward, from effect to cause ), a priori (from what comes before, from cause to effect ). These terms are often used to indicate relations of cause and effect (see causality). In scholastic logic, a posteriori would refer to the inductive process of immediate experience necessary for arriving at a universal proposition; this proposition, in turn, is used in a syllogism as an a priori premise to a new conclusion. Both processes take place in common knowledge. From the sight of smoke we conclude that there is a fire (a posteriori ); knowing the quality of fire, we warn that it will burn one's hand (a priori ). see induction; deduction.
De facto (in fact ), de iure (by right ). De facto expresses what the situation actually is; de iure indicates what it ought to be. A military clique rules the country de facto, although a civilian has been legally elected de iure.
Ens actu (actual being, being in act ), ens potentia (potential being, being in potency ). A monumental contribution to philosophy is the distinction between potency and act introduced by Aristotle. Found throughout his works, the distinction is first made when he is analyzing the meaning of nature (Phys. 192b 10), and has undergone further development and refinement by the scholastics. Actual being refers to any being—whether substantial or accidental, natural or artificial—that is here and now exercising actuality, such as seeing by an eye, the living of a man, or the existence of a tree or a painting. Any kind of existence can be included under actual being, including even that of logical beings, which exist only in the mind. Potential being refers to a real capacity on the part of any being to be something more, to do something, or to become something. The eye closed but healthy is in potency to see, the tree bare of leaves is in potency to blossom, the seed can become the flower, and propositions in the mind can be united to make a syllogism. St. Thomas puts the whole distinction briefly: "Now a thing is said to be a being in two ways: first, simply, i.e., whatever is being in act; secondly, relatively, i.e., whatever is a being in potentiality" (Summa theologiae 3a, 10.3). see potency and act.
Ens rationis (being of reason ), ens reale (real being ). "Being is twofold, namely, being of reason and being of nature. A being of reason is properly called one of those intentions which the mind discovers in the things considered, such as the notion of genus, species, and the like which indeed are not found in reality but follow upon the consideration of the mind. Of this kind, namely, being of reason, is properly the subject of logic." (St. Thomas, In 4 meta. 4.574.) Real being is that which exists independently of the human mind, and is known as ontological being. Hence, all objective reality is embraced under real being. (see intentionality.)
Formaliter (formally, present according to the intrinsic form ), virtualiter (virtually, present according to the intrinsic power ), eminenter (eminently, present according to a more excellent mode ). These three terms indicate the different ways in which one thing is contained in another. A quality is formally in something if it is actually present in the very definition of the thing, e.g., reason is formally in man because we must refer to reason in order to define man. A quality is virtually in something if it can be produced by that thing, as every effect is virtually in its cause. A quality is eminently in another when contained in a more excellent way, as the human soul in man can do whatever vegetative and sensitive souls do in plants and animals, and more besides (see distinction, kinds of; soul, human).
In fieri (becoming, in the process of being made ), in facto esse (made, in real and complete existence ). These terms are used by Aristotle to help explain the reality of change. Using an example from art, he writes: "Take for instance the buildable as buildable. The actuality of the buildable as buildable is the process of building. For the actuality of the buildable must be either this or the house. But when there is a house, the buildable is no longer buildable" (Phys. 201b 9–14). Whatever has not attained its end, terminus, or perfection but is moving towards it, whether in nature or in art, is described as becoming, or "in the process of being made" what it is meant to be. The goal of the becoming is the completed being. Once this goal is attained, then the thing is; it has reached its completion in its line of existence.
As used by Aristotle in his works on nature, these terms refer primarily to generation and growth. However, the terms have been adapted to many other aspects of philosophy; they appear also in theology, where philosophical principles are often used to facilitate doctrinal explanations. Thus St. Thomas applies the distinction when writing on the change in the Eucharist: "In instantaneous changes a thing is in becoming (in fieri ), and is in being (factum esse ) simultaneously, just as becoming illuminated and to be actually illuminated are simultaneous. In such cases, a thing is said to be in being (factum esse ) according as it now is; but to be in becoming (in fieri ) according as it was not before" (Summa theologiae 3a, 75.7 ad 2).
Medium quod (the means which ), medium quo (the means by which ), medium a quo (the means from which ), medium sub quo (the means under which ). These terms are employed to assist in understanding the theory of knowledge. The so-called medium quod is not really a medium or means in the strict sense; it refers rather to the object itself that is to be seen or known. The remaining three terms indicate true means of knowing, as is evident from the following: "In any seeing a threefold medium can be considered. One is the medium under which (sub quo ) it is seen; another is that by which (quo ) it is seen, which is the species of the thing seen; another, from which (a quo ) the knowledge of the seen thing is taken. Thus, in bodily seeing the medium under which (sub quo ) it is seen is the light by which something is made actually visible and the sight is perfected for seeing. The medium by which (quo ) it is seen is the very species itself of the sensible thing existing in the eye which, as the form of the one seeing inasmuch as he is seeing, is the principle of visual operation. The medium from which (a quo ) knowledge of the seen thing is taken is as a mirror from which, meanwhile, the species of any visible thing, as a stone, is made in the eye, not immediately from the stone itself" (St. Thomas, De ver, 18.1 ad 1). see species, intentional; concept.
Natura naturans and natura naturata. Neither term is translatable and neither had extensive use among scholastic philosophers. The following gives some idea of the distinction. Natura naturans: (1) is used to refer to God as the author, preserver, and ruler of nature; or (2) signifies nature taken universally as constituting the essence of particular things. Natura naturata: (1) is used to express the totality of created reality; or (2) indicates the universal nature particularized in the singular thing. [See H. A. Lucks, "Natura Naturans—Natura Naturata," The New Scholasticism 9 (1935) 1–24.]
Numerus numerans (number counting ), numerus numeratus (number enumerated ). "Number is said twofoldly. In one way, as that which actually is numbered or which can be numbered, as when we say ten men or ten horses. This is called a number enumerated because the number is applied to the things counted. In another way number is said as that by which we number, that is, the number itself taken strictly, as two, three, four" (St. Thomas, In 4 phys. 17.11). The latter exists in the mind only, while the former is considered as existing outside the mind since it refers to the reality that is counted or numbered.
Obiectum formale (formal object ), obiectum materiale (material object ). The formal object is that definite, precise characteristic of a complex whole that engages a vital power, that is, the special, primary, immediate aspect considered or sought in a material or total object. Thus, for example, color is the formal object of sight.
The material object is the total object or the thing in all its reality, and not merely the particular feature falling under the action of a power, habit, or act. It is the general or common subject matter, rather than the specialized feature of study or the limited point of view under which the subject is attained. Thus, all colored physical things are the material object of sight. (see concept; knowledge.)
Ordo intentionis (the order of intention ), ordo executionis (the order of execution or accomplishment ). Used conjointly, these terms refer to the final cause along with the means used for attaining an end. Before attempting to achieve an end, the mind ascertains whether the end is possible and attainable. Then the mind works on the means for obtaining the end, as a sculptor conceives the figure he intends to make and then gathers the material and instruments for making the product. The correlation of these two terms gives rise to the expression: What is first in intention is last in execution. Thus, the artist first conceives what he wishes to make, and this conception of the end product is prior to the operations that he performs to bring it into being; but in the order of reality the finished product is ultimate, the last thing achieved. In the moral order, the happy coordination between the orders of intention and execution constitutes the virtue of prudence.
Per se (through itself, directly, essentially ), per accidens (through another, indirectly, accidentally ). These terms are used extensively in philosophy and theology. St. Thomas writes: "Whatever are in another thing through themselves (per se ) either are of its essence or follow upon essential principles…. Everything present to another thing accidentally (per accidens ), since it is extraneous to its nature, must pertain to it from some exterior cause" (De pot. 10.4). Such is the basic distinction, and its applications to causality, natural and artificial objects, modes of composition, methods of speaking, etc., are almost without limit. A few illustrations will show the wide variety of ways in which the terms are employed. A room is illumined directly by the sun, and accidentally by the person who pulls up the shade so that the sun can shine in. The doctor cures as doctor (per se ), and indirectly by reason of his race or religion. Rationality belongs to man essentially (per se ); his nationality belongs to him accidentally. (see predicables.)
Pons asinorum (asses' bridge ). Although of earlier origin, in philosophy this term was applied to the diagram that Peter Tartaretus constructed to assist the student of logic in the discovery of the middle term of a syllogism. The expression suggests that getting students of logic to find the middle term of a syllogism was as difficult as getting asses to cross a bridge.
Propter quid (on account of which ), quia (because, the fact that ). These terms refer to different types of logical demonstration. When the proper cause is given for establishing a conclusion, the demonstration is termed propter quid. Thus, from the truth that man is a composite being, we can establish by a propter quid demonstration that he is also a mortal being. In such logical demonstrations, which proceed from proper and immediate causes, the predicate is a property of the subject and the middle term of the syllogism is a definition of the subject. When the proper cause is not known, an effect (or in some instances even a remote cause) is sought as a basis for establishing the validity of the conclusion. This is demonstration quia, or demonstration simply of the fact; the proofs for the existence of god are demonstrations of this sort. Demonstrations from the proper or remote causes are also known as a priori, while those demonstrations from effect to cause are a posteriori.
Quo est (that by which a thing is; existence ), Quod est (that which is; essence ). These terms have a wide variety of usage, and their full implications have been the subject of one of the most intense debates within scholasticism. The problem concerns the real distinction between essence and existence. Essence refers to the thing that exists; hence it is "that which is." Existence is the act that places the essence in the realm of existing beings; thus, it is "that by which" the essence or thing exists. All scholastics admit some kind of distinction between essence and existence, and consequently recognize these terms as valid. There is much dispute, however, as to the kind of distinction. (see essence and existence; distinction, kinds of.)
Regressus in infinitum (infinite regress ). This expression is especially canonized by reason of the first three proofs for the existence of God as set forth by St. Thomas (see god, proofs for the existence of). An infinite regress refers to an endless series of causes in which no beginning is postulated. The infinite regress cannot explain the evident fact of motion, the order of efficient causes in sensible things, or the contingency in nature. An infinite regress would deny the real distinction between potency and act that is clearly involved in motion, efficient causality in the sensible order, and contingency. The infinite regress is impossible among things essentially related as cause and effect; in other words, the effects here and now realized are still essentially dependent upon a first mover, first efficient cause, and necessary being. However, it is possible to have an infinite regress where an accidental line of causality is involved, i.e., one wherein the present effect has no real dependence for its existence upon the previous causes; thus, a man once generated can continue to live even though his parents die.
Sic et non (yes and no; this way and that; for and against ). Peter abelard used these words as the title of a work in which he gathered genuine and apparently opposing opinions from the early Church writers on doctrinal and moral points, leaving the conflicts unresolved. Examples of Abelard's technique to arouse doubt, then inquiry, and finally to attain the truth are such propositions as: "No one can be saved without baptism of water; one can be saved without baptism of water." "At times we sin unwillingly; we always sin willingly." This method was later adopted, with modifications, into the Summas of such writers as peter lombard and St. Thomas Aquinas. (see scholastic method.)
Simpliciter (simply, strictly, absolutely, under every aspect ), secundum quid (after a fashion, in some way, partially, relatively ). These terms have wide application, as is evident from a few citations. "The superiority of one thing over another can be considered in two ways, strictly (simpliciter ) and relatively (secundum quid )" (Summa theologiae 1a, 82.3). Then follows a comparison of the intellect and will. Again: "The expression simply (simpliciter ) can be taken in two senses. [In one sense it means] the same as absolutely…. In another way, simply is the same as altogether or totally" (Summa theologiae 3a, 50.5). Simpliciter and per se are frequently used interchangeably, as are secundum quid and per accidens. Thus, we speak most rigidly and strictly when we talk per se and simpliciter, while we are less formal and exact when we speak per accidens and secundum quid.
A few illustrations will make evident the value of this distinction. God is simply eternal; that is, He is without succession of past, present, and future. Such is the strictest significance of eternal. Man's soul, on the other hand, is relatively eternal; that is, it will never cease to be, but never does it embrace its complete existence in an eternal now. Again, a rose that has all that pertains to its perfection is good simply; one that lacks a due perfection, e.g., a pleasant fragrance, is only relatively good. St. Thomas employs a more subtle use of the distinction when he points out that by reason of substantial existence a thing is strictly a being, but good only after a fashion, that is, only by reason of its being. Yet, when the thing has its ultimate perfection it is said to be a being after a fashion and good strictly or absolutely (Summa theologiae 1a, 5.1 ad 1).
Species impressa (impressed species ), species expressa (expressed species ). These terms are employed for explaining details of the process of ideation. Man's intellect somehow attains universal knowledge of the particular objects perceived by his senses. In order to explain how this is achieved, Aristotle postulated an active intellect that abstracted and dematerialized the sensible species formed by the imagination, and a possible intellect that received this dematerialized species and thus formed the idea by which man knows. The form produced by the active intellect is the impressed species; that produced by the possible intellect, i.e., the idea, is the expressed species.
These terms are also employed in reference to the sensible order. Here, the impressed species is the result of the external stimuli of the object upon the sense organ; the expressed species is a phantasm formed by the imagination as a result of the stimuli communicated to it from the external sense organs. (see species, intentional; idea.)
Sui generis (unique, of its own kind, in a class by itself ). This expression comes from the logical device known as the predicables. A genus is a universal that normally is said of many species, as animal is said of man, dog, cat, etc. When a thing is such that it is the only one of its kind, so that its nature cannot be predicated of anything other than itself, it is called unique or sui generis.
As in the case of terms, here again an attempt has been made to list the axioms most frequently employed by the scholastics in the elaboration of their syntheses, with stress on the interpretation given to Aristotle's thought by St. Thomas Aquinas.
Ab esse ad posse valet illatio (From actual existence, the possibility of existence is validly inferred ). From the fact that something is known actually to be, we rightly judge that it is possible for it to be. We know that eclipses of the sun and earthquakes are possible, even though they are not normal occurrences, because in fact they do sometimes happen. This axiom has wide application in philosophy, especially in natural philosophy and metaphysics, and it is also of great importance in Catholic apologetics. For example, the most effective proof that miracles are possible is the fact that they have been known to take place.
Abstrahentium non est mendacium (The work of abstracting is not a lie ). When one leaves aside certain real and concrete characteristics of an object in order to study one aspect more perfectly, as the mathematician does with lines and number, no deception or falsehood is involved provided that the fact of leaving out the other traits is never denied. Aristotle makes this point when discussing how the mathematician considers physical reality: "Now the mathematician, though he too treats of these things, nevertheless, does not treat them as the limits of a physical body … that is why he separates them; for in thought they are separable from motion, and it makes no difference, nor does any falsity result, if they are separated" (Phys. 193b 34). The very truth of universal knowledge and of science depends on the validity of this axiom. (see abstraction.)
Actiones sunt suppositorum (Actions are of the individual ). The subject of an action is not the part, as the hand, or an organ, as the eye, or even the form, as the soul, but the individual substance. For example, a man strikes another not immediately through his substance, but mediately through the action or operation of his hand; the act of striking, however, is attributed properly to the man rather than to his hand (cf. St. Thomas, (Summa theologiae 2a2ae, 58.2). The individual is the incommunicable substance, and when that is a man it is called a person. This axiom is important in treating of Christ, who is the God-man having the divine and human natures. His actions are of His Person, which is divine and not human, and hence they have infinite value; for the dignity and worth of an action is taken from its subject, which is the individual.
Actus est prior potentia (Act is prior to potency ). Aristotle develops this axiom in his Metaphysics (1049b 4–1050a 29). The expression can be understood in a number of ways: (1) Act is prior to potency conceptually. This means that act by its definition is prior to potency, because potency can be defined only through act. Thus, we define a singer as one able to sing, i.e., one in potency to perform the act of singing. (2) Act is prior to potency naturally. What is completed or perfect is superior to what is only in potency. Hence, the adult is more perfect than the child. (3) Act is prior to potency temporally, although there is a sense in which act is temporally posterior to potency. In the order of generation, what is less perfect precedes what is more perfect, as the seed precedes the flower. Thus, potency is prior to act in the sense of the potential advancing to greater perfection. Nevertheless, act is prior to potency in the sense that nothing can be reduced from potency to act except by something already in act; thus, nature is actually moving the seed toward its perfection as a flower (cf. St. Thomas, (Summa theologiae 1a, 85.3 ad 1). see potency and act.
Actus limitatur per potentiam (Act is limited through potency ). Act is perfection, and, precisely as perfection, cannot contain any limitation. Hence, any limitation of act must come from an extrinsic principle, namely, potency, which is the real capacity to receive act. Thus, the human soul is a life-giving principle, but each soul is restricted in its act to the body that it vivifies. From this principle it also follows that act, in the material order, is multiplied through potency; thus, we have many men because many bodies receive the many human souls. (see individuation.)
Agere sequitur esse (Acting depends on being ). This axiom confirms the essential correlation between existence and operation, between the being and the activity of a thing. One understanding of the principle is that just as a being is, so does it operate. Thus fire, being hot, generates heat and not cold. Another meaning intended is that being has priority in nature to acting, although not necessarily in time. Striking a match results in flame and, simultaneously, in the heating and illuminating that result from the flame. (Cf. St. Thomas, C. gent. 3.69; Summa theologiae 3a, 34.2 ad 1.)
Bonum est diffusivum sui (Good is diffusive of itself ). Good adds to being the notion of desirability. Then, acting in the mode of a final cause, good attracts, elicits, and moves the efficient cause. In this way, good is said to be diffusive of itself or to communicate its goodness. Thus a good person by his very example of virtue inspires others and influences them to be good. However, pseudo-dionysius in De divinis nominibus employs the expression in relation to God, comparing God to the sun, which spreads its light everywhere. God is the total cause of all that is good, and is both the efficient and final cause of goodness. "Good as substantial good extends goodness to all existing things" (4.1.95). see neoplatonism; emanationism.
Bonum ex integra causa (Good results from integral totality ). What is perfect is good, but nothing is perfect that lacks what belongs to it; a blind man is imperfect because he is deprived of sight, a perfection due to him. Perfect health would require the complete harmony of the whole body; the presence of even a single defect (such as the lack of sight) results in the physical evil of sickness. Thus, as Pseudo-Dionysius states, "Good is from one total cause; evil is from many particular defects" (De divin. nom. 4.30.237). This axiom has great importance in the moral order, where the goodness of an act must be determined from its object, end, and circumstances; a defect in any one of these results in an evil act. Thus, the pride that motivates the giving of alms vitiates what otherwise would be a good deed. (see morality.)
Causa cessante cessat effectus (The cause ceasing, the effect ceases ). This is true only in those effects that depend on their causes both for their becoming and their being. A book depends on the hand supporting it against gravity in order both to be where it is and to remain there. St. Thomas explains the principle at length when treating of God's conserving power in creatures ((Summa theologiae 1a, 104.1). see causality; conservation, divine.
Ens et unum convertuntur (Being and one are convertible ). Being and one are transcendentals, extending themselves to everything. Whatever is, is being, because being is the subject of existence. Being and one are subjectively the same, but one signifies the notion of indivision or undividedness. One, thus understood, must not be confused with homogeneity. Man, though heterogeneous in his many parts, is one; that is, he is undivided in himself since he is a human being, and not many beings by reason of his parts. The principle means that whatever is, is one in this transcendental sense. Hence we can say that whatever is, is one, and whatever is one, is. (Cf. St. Thomas, In 10 meta. 3.1974–80.) see unity.
Ex nihilo nihil fit (From nothing, nothing comes ). When the "from" refers to the material cause, then truly nothing can result from nothing. However, when the "from" refers to the order of events—as in creation, first there was nothing and then something—then the axiom is not valid. The formulation of the axiom is from the Eleatic school of philosophy. (see greek philosophy.)
Generatio fit in instanti (Generation is instantaneous ). Acceptance of this axiom presupposes the hylo-morphism of Aristotle. Fundamentally and ultimately, each material thing is composed of prime matter and a substantial form (see matter and form). The substantial form determines what the thing is. No substance, therefore, can have more than one substantial form at any given moment. Were not substantial change or generation instantaneous, however, a substance would have two specifying forms at the same time, and thus it would be two different things simultaneously. (see substantialchange; instant.)
Generatio unius est corruptio alterius (The generation of one thing is the corruption of another ). The fact that nature perpetuates itself is evident. How these changes are explained has puzzled men of every age. Aristotle has summarized his doctrine in the dictum: The generation of one thing means the corruption of another, and the corruption of this means the generation of that (Gen. et cor. 318a 25–27). It is evident enough that when wood is burned, ashes remain. The more profound problem is with such living changes as the development of the seed into the plant. The seed perishes, giving way to a higher form of life; the passing of the plant, in turn, means the disintegration of the power (the form) that maintained its inner harmony of parts. Obviously the principle is not meant so literally as to suggest that the corruption of this plant means the generation immediately of a new one; rather, the plant during its own existence produces seeds that will develop into new life. As with the preceding axiom, the acceptance of hylomorphism makes the principle more understandable. Prime matter is never without a substantial form. Consequently, when a change takes place in any substance, its loss of one form immediately calls forth the form of another. (see matter and form; generation-corruption.)
Individuum est incommunicabile (The individual is incommunicable ). The individual is undivided in itself, but is divided from everything else by reason of its ultimate completing element. Understood in this way, the term individual refers to the concrete, particular sub-stance that is complete in its own line of essence and existence. In other words, unlike the universal or genus, an individual cannot be predicated of inferiors; that is, it cannot have species under it. Furthermore, the individual cannot communicate its nature to another in the sense of constituting another's essence out of its own. The axiom does not refer to efficient causality, let alone deny it. Thus flame does communicate its heat as well as increase itself when burning new material; man does generate man, as well as communicate his ideas to others. Yet, in these cases the individual as such is not associated with its effects or products in such a way as to constitute their essence; rather, its powers are exercised in bringing about a change in other individuals. (see individuality; individuation.)
Intellectus fit omnia (The intellect becomes all things ). Not physically but conceptually, man's mind becomes everything he knows. The existential order outside man's intellect is impressed upon his senses and eventually abstracted and universalized. Thus, after this intentional mode, the intellect is made what it knows. (see abstraction; universals.)
Nemo dat quod non habet (No one gives what he does not have ). The proper nature of causality shows that the cause cannot produce an effect with qualities superior to the cause itself. This axiom is expressed in many popular sayings, such as "You can't make a silk purse out of a sow's ear."
Nihil est causa sui ipsius (Nothing is the cause of itself ). To be its own cause in the order of substantial being, a thing would have to be and not-be at the same time. The thing would have to not-be, for if it already were, it would not have to be caused. Yet, it would also have to be, since causality is an action or operation, and act follows upon being. Hence, the notion of something's causing itself is self-contradictory. (see causality, principle of.)
Nihil est in intellectu quod prius non fuerit in sensu (Nothing is in the intellect that was not first in the sense ). Man is composed of body and soul, operating according to the demands of his composite nature. Although the intellect is immaterial, while united to the body it depends on phantasms that were gathered by the various senses. Man's normal acquisition of knowledge is not intuitive, but is an abstracting process beginning in the external senses.
Omne agens agit propter finem (Every agent acts for an end ). This axiom is a statement of the principle of finality and means that every active or efficient cause tends toward that which is good or agreeable to it, whether without knowledge, as in purely natural movements, or with knowledge, as in those of the sense appetite or under the command of reason. (see finality, principle of.)
Omne quod movetur ab alio movetur (Everything moved is moved by another ). The movable is in potency even while in motion, for it is in potency to that toward which it is being moved. Since nothing can reduce itself from potency to act, but depends on a being already in act, it follows that the mover and the moved are distinct, just as are potency and act, and that act absolutely considered is prior to the actualization of the potency. (see motion, first cause of.)
Potentia et actus dividunt omne ens (Potency and act divide all being ). Whatever is, either is pure act or is intrinsically composed, in its ultimate metaphysical refinement, of potency and act. This principle is at the pinnacle of scholastic thought and upon its validity stands the perennial philosophy. God alone is pure act; all beings other than God are in some way potential as well as being in act. The source of the distinction is natural philosophy; act and potency primarily pertain to the mobile order, since this order depends upon them. Yet, the mobile order and the order of being as such, i.e., the metaphysical order, are materially the same in extension. Consequently, all being, materially speaking, is either potency or act. Indeed, even formally being is either one or the other, for potency and act verify in themselves the formality of being, and are therefore coextensive with being (cf. St. Thomas, Summa theologiae 1a, 77.1).
Potentiae specificantur per actus et obiecta (Potencies are specified through their acts and objects ). Every potency is of its very nature ordered to some act, but act on its part must be about some object. Thus, the powers of the eye and ear are ordered respectively to seeing and hearing, which in their turn must be immediately and properly related to some objects, namely, color and sound. Accidental differences in the colored or sounding objects do not so specify as to require a new potency for each act of seeing or hearing. (see faculties of the soul.)
Propter quod unumquodque tale et illud magis (Whatever makes a thing to be in a certain way, is that and more so ). Whatever is the cause of any formality or perfection in other things, itself possesses that formality or perfection in a greater, more eminent degree. If water is made hot by a fire, then the fire possesses heat more perfectly than the water, let alone the other things made hot by means of the hot water. The axiom is found in Aristotle: "A thing has a quality in a higher degree than other things if in virtue of it the similar quality belongs to the other things as well" (Meta. 993b 24). see participation.
Quidquid recipitur ad modum recipientis recipitur (Whatever is received is received after the mode of the one receiving ). A proportion exists between the receiver and the received, as between potency and act. The receiving subject has a certain capacity and disposition, determined by its nature, for receiving some act. It is according to the greater or lesser capacity of the receiver that something is received, as, in teaching, the pupils receive the imparted knowledge according to their respective intellectual capacities. see education, philosophy of.
Verum et bonum convertuntur (Truth and good are convertible ). Everything true is good and everything good is true. True and good are transcendentals, each adding to being merely a new relation. truth is being related to the intellect; good is being related to the appetite. The principle refers to the ontological good and true, and hence, does not refer directly to the moral order.
Virtus consistit in medio (Virtue is found in the mean ). Aristotle's basic principle of good moral action is to place virtue between two extremes that are called vices. Virtue is the good habit whose act avoids the extremes and maintains the mean of honest living. Aristotle puts it in this way: "Virtue, then, is a state of character concerned with choice, lying in a mean, i.e., the mean relative to us, this being determined by a rational principle, and by that principle by which the man of practical wisdom would determine it" (Eth. Nic. 1107a 1–3).
Bibliography: r. j. deferrari et al., A Latin-English Dictionary of St. Thomas Aquinas Based on the Summa Theologica and Selected Passages of His Other Works, 5 fasc. (Washington 1948–53). t. w. wilson, An Index to Aristotle in English Translation (Princeton, N.J. 1949). d. d. runes, ed., Dictionary of Philosophy (Ames, Iowa 1955). Enciclopedia filosofica 4.1859–62. n. signoriello, Lexicon peripateticum philosophico-theologicum … (Naples 1906; Rome 1931). petri de bergomo, Tabula aurea (Photocopy from Thomas Aquinas's Opera Omnia, Editiones Paulinae; Rome 1960).