ACT AND POTENCY (Greek ενεργεια [energeia]—δυναμις [dynamis], παθη [pathe]; Latin actus—potentia)—mutually ordered factors or components (ordered in different orders) of one being, in which act and potency are respectively: form and matter, substance and accidents, existence and essence, and thus that which determines and that which is determined, that which subordinates and that which is subordinated, that which is real and that which is possible in a concrete being.

THE HISTORY OF THE ORIGIN OF THE THEORY OF ACT AND POTENCY. Aristotle formulated the theory of act and potency in his discussion with Plato and Plato’s predecessors. They saw in the world’s reality many dynamic and potential aspects, as well as static and determining aspects, but they did not formulate a synthesis of their correct intuitions. Aristotle’s conception of act and potency is one of the greatest achievements of human thought. He synthesized the philosophical explanation of reality in its various changes and states of being and in the general "decontradictifying" knowledge of reality. His explanation consisted in showing a factor whose negation would be a negation of the fact of the being that is to be explained. The conception of act and potency is the culminating and general theory of all compositions in being, both in existence and in action, which is the manifestation of dynamism in being. There are many compositions in a concrete being. The compositions that are distinguished in a philosophical analysis—of substance and accidents, matter and form, essence and existence—are not the only types of composition, but they are the “perfective compositions” that are associated with different types of qualities in beings, especially in human conduct that is developed by habits. Besides the category of quality, there are many other categories composed in different ways, whose composition is noncontradictory only when they form one category of being and are related to one another as potency to act. This allows us to have a more profound understanding of a being that is contingent and variable, and yet the same being.

Aristotle discovered potency and act while examining his predecessors’ one-sided explanations of reality. They pondered the character of reality and asked about its beginning or arche (αρχη). Their first answers focused on the material element from which everything arose and persists in its existence. The Greek mythologists first indicated material elements, such as “chaos”, “night”, “Oceanos”, and “Styx”. These were indefinite and undetermined factors. They were in a sense non-beings, if being was understood as a determination or a stable and necessary content. The idea that the beginning (arche) was some radically indeterminate element and something that was almost a non-being could not, thought Aristotle, result in knowledge, since the being and reality in which we live could not have arisen from non- being.

The thought of the mythologists was reinforced by the later speculations of Heraclitus and Anaxagoras. Heraclitus thought that the world is in contact flux, for everything is changing and nothing endures: παντα ρει και ουδεν μενει [panta rhei kai ouden menei]. Only change and motion exists, which was expressed by the metaphorical saying: “one cannot step into the same river twice”. The “war” of all forces among themselves is the father of all that exists. There is in the world no stable element, no subject that would endure as the same. Anaxagoras conceived of reality also as a radical mixture of everything with everything. The krasis (κρασις) of Anaxagoras was this primal “chaos” from which all reality would emerge. They conceived reality as a great and radical change manifested in restless and all-comsuming fire. Is there only change in reality?

Without doubt, Anaxagoras and Heraclitus postulated the existence a reason such as Nous (νους) or Logos (λογος), but Aristotle emphasized the potential aspect of reality and ignored the matter of the Logos and the Nous of Anaxagoras. Most likely, Aristotle wanted to emphasized that the philosophers he cited had a one-sided approach: for them reality would have been radically potential. Aristotle could not be satisfied with such a vision of reality, since it was not in agreement with reason, its function of knowing, and its rational order, which is basically rooted in reality. Aristotle as a Platonist placed too much value on the rationality of knowledge to agree with a vision of reality that was only potential. For this reason he opposed it with a contrary vision of absolute rationality, also emphatic. This vision was associated with a static image of the world as Parmenides and the Eleatic school had proposed. For Parmenides, a being identical with itself, unchanging, single and not subject to any motion or becoming, was the only reality. Such a being as an object of thought appeared as identity formulated in absolute terms in the form of the principle: “being is being”. Therefore no changes could occur. There were no transitions from non-being to being, or from being to non-being, since there was no non-being. The principle of identity is accessible only to the intellect and is the chief law of the intellect. This law is the basis of radical rationality and the way of the “sages”, as opposed to the way of “fools” in which there appears plurality, change and individuality in beings. The Eleatics, with Zeno at their head, likely did not want to acknowledge change and motion. They were convinced that motion is impossible because it implies contradictions.

Aristotle understood these two opposed views that tried to explain reality. Radical mobilism did not acknowledge any enduring structures that could be an object of necessary cognition. The static point of view professed only immobilism, which rejected motion and change while holding to the principle of identity. Both the mobilism of Heraclitus and the immobilism of Parmenides and the Eleatics arrived at monistic positions, or positions approaching monism, in their interpretation of the world. It would be difficult, however, to reject completely the achievements and interpretations of both these schools, since both had discovered something real in the world and presented explanations that were realistic in some respects, even if one-sided.

Aristotle made a synthesis of these two positions and accepted what truth he found in both interpretations. He said that reality is neither exclusively potential, nor exclusively static, but in different aspects it is dynamic and static. It provides the foundations of necessity for our knowledge and for performing an abstraction from motion or change and individuality, which are associated with the mobilism of a thing. Although reality is dynamic, potential, and changing, at the same time it has in itself certain necessary, identical and static structures. Reality is “composed” of a factor or factors that are “potential” and which influence the change and dynamism of being, and at the same time reality possesses in itself factors which “actualize”, determine and make necessary existence, and so also actualize, determine and make necessary the knowledge of the being. This was the discovery of the “composition” of being of potential and actual factors. Act—energeia (ενεργεια) and entelecheia (εντελεχεια) —is the basic side of a thing that at the same time is changing and possesses dynamis (δυναμις)—the potency for change in an active and passive sense. This vision provided a way out of the paradoxes of mobilistic mobilism and static mobilism, and at the same time led to a more profound explanation of the phenomenon of motion and provided a basis for a knowledge of things in necessary terms.

REASONS FOR ACCEPTING ACT AND POTENCY IN REAL BEINGS. Aristotle provided rational justifications for act and potency in really existing beings He showed: (1) that the observation and analysis of motion or change is noncontradictory only when being is constituted of act and potency; (2) that the principle of non-contradiction can be truly binding in the real world only if the world has a structure of act and potency; (3) we can call upon the common sense experience of those who for various theretical reasons rejected the composition of being of act and potency, as did the authors of the Megarian school.

Ad 1. Motion and change are most evident in the world; hence the phenomenon of motion evokes acts of cognition among animals and men. Motion and change do not exist apart from beings, but are a state of being in its various categories of substance and accidents. In the fact of motion we primarily consider its act, namely the agent that determine action (motion)— i.e., spatial changes in locomotion, or qualitative changes such as becoming warm or becoming white. However, this act is not completed; it is not in the state where motion ceases. Such an act therefore is in the state of the further perfecting of the being. An act that is still being completed perfects, determines, and organizes organized elements (e.g., the building of a house, upbringing of children, learning)—when such an act is in an imperfect state, it is an act in potency to completion. It is in potency to the full determination and organization of the elements in which motion occurs. The fact of motion and transformation in a being reveals its state as an act moving toward completion, and its state of a potency that is being completed by motion. Hence Aristotle described motion as “an act that is in potency as such” (Met., 1065 b 16). The same real being is therefore the object that is is a real potency to actualization in a motion or transformation. Act and potency are real states of the same being that is subject to motion and transformations. A real potency in being may be further or closer to the various acts that a being gains by transformation or motion. Only act and potency can provide an explanation for the phenomenon of motion and reveal its essentially integrating factors.

Descartes attempted to define motion by linking matter’s powerlessness and forces “from the exterior”, and Hegel tried to define motion in terms of the internal “contradiction” of being that is evoked in “becoming” as the “liberation” of being. Both these solutions are unacceptable in philosophy, since they start from wrong a priori premises, yet even wrong conceptions in some cases seem to fit reality, although they do not explain reality.

Ad 2. Aristotle notes that if our cognition is realistic, namely if the contents of our cognition depend upon being, then both the mobilistic monism of Heraclitus and the radical immobilism of Parmenides are contrary to the observed state of things (namely with the fact that we affirm the determinants of being despite the position of mobilism, and we affirm potentiality and motion), and they are contrary to to the principle of non-contradiction. If Parmideanism were true, that “only one being exists”, then necessarily man and non-man would be the same. This is an absurdity. If only mobilism were true, then by the same token we would have to reject the principle of non-contradiction, since then everything would be everything and there would be no distinctions in things. If we hold to the principle of non-contradiction and reject both of these radically monistic theories, we should acknowledge that there is both determination (act) and motion or tranformation (potency) in things.

Ad 3. The Megarian school was established on the Isthmus of Corinth by disciples of radical Platonism after Plato’s death. They held that only ideas exist and rejected changing and potentiality in things. Aristotle carried on polemics with them. He appealed to the “common sense” that was common to all people. The Megarians (Diodorus of Cronus, Eucleides of Megara) held that knowledge was characterized by necessity, and the objects of knowledge also were characterized by necessity and invariability. Aristotle appealed to “common sense” and noted that the expression “house- builder” (οικοδομος [oikodomos]) implied the possibility of building a house, not merely the act in which a house comes into being. To deny that this is possible is to deny all art and craftsmanship. Craftsmen are people who have a real potency for the actualization of their domain of art. The same happens with real potencies in nature. If no real potency existed, we would have to deny the harvest of grain after the time of sowing and growth, the gathering of grain when it becomes ripe, the possibility of waking a sleeper, the upbringing of a child, or the training of a citizen to work in society. All these potencies are real and anchored in being. They are part of the structure of being. In a being, apart from the act that determines the being to a particular identity of content and not some other, there is still a real potency for actualization according to the rules of nature or the rules of art. To deny this is to eliminate the action of nature or art, and thereby that of culture as a whole. In real life, we cannot rely on the radical and a priori speculations of philosophers that do not take into account real life.

WHAT ARE POTENCY AND ACT? For Aristotle and Thomas Aquinas, the theoreticians of potency and act, being is the object of our knowledge. We know real aspects in an existing being: the potential aspect and the actual aspect. In the First Being, what we conceive is his act. Aristotle called act “energeia” (εν- εργον [en-ergon]—work) and “entelécheia ([εν- τελος- εχειν [en-telos-echein]—to achieve the end]; act is most evident upon the background of motion that aims at something as its completion—and its aim is act as something fulfilled, performed, perfect, as an end or term. Aristotle held that act “is that which makes a thing be, but not in the same way as it is when it is potency” (Met., 1048 a 30). Therefore we conceive act upon the background of motion as the realization of motion, as the actualization of the potentiality of a being. In real states of ordering or relation, the intellect reads the evident content of act and potency. Act understood as motion appears primarily as action, namely as the fulfillment of an active potency, or act is present to the intellect as it reads being as the ultimate perfection and determination of being, as “entelécheia”, namely as the final fulfillment of being and, as a result of transformatios, the achievement of a determination and “form of being” which is an actualization of a passive potency.

We read out potency in being by its ordering to act, and so we speak of “passive potency” which is the “source of change in some other thing, or in the same thing qua other” (ibid., 1045 a 11), and “active potency” which is the reason for a change in another being (or itself) as other. The manifestations of potency can be found in all the faculties of action, such as the senses, the reason, the will etc.. The basic manifestation of potency is passive potency, since it is ultimately opposed to act. Active potency also subordinate to an act, for it operates in the measure in which it is somehow “set in motion” or “actualized”. Thus the opposition of potency and act basically concerns act and passive potency, which is an ordering (according to the dispositions of nature or dispositions introduced by art) to act. Potency is known by way of act; it is ordered to act, but there is a privation or stéresis (στερησις) of that act within it.

Now that we distinguished between potency and act, we should examine how they are concretely manifested in really existing being. We may distinguish: (a) objective potency, or pure potency, which is a non-contradictory system of concepts. Sometimes this is called intentional potency. It is not the real potency of which metaphysics speaks; it is not realized in any concrete being as a subject; (b) subjective potency, namely real active potency, which as the reason for the transformation of another being is “reducible” to passive potency and “mixed” with act in various categories of being, and so in substance and accident; (c) pure passive potency, which is “prime matter” as the ultimate term in the real explanation of substantial changes.

Potency thus understood is always an ordering to act, and it helps us to understand the character of act in being—“pure” immanent action, e.g., cognition. Act as perfection concerns: (a) active potency—active potencies are acts of real action that lead to a product; (b) passive potency—these are forms of accidents depending upon the potentiality that the form perfects (quantity, quality, relation, etc.), the forms of perishable substances, of substances with cognition, and indestructible substances (such as angels and demons); the pure form, which is the Aristotelian god who is the ultimate act. An act is an end in real intention, and a “work” in its execution.

The above outline sets in order our understanding of act and potency. It primarily concerns Aristotle’s system, since in the conception of being as it was further developed by Thomas Aquinas, the conception of being takes on a fuller character, where God is Pure Act as Pure Existence. For Aristotle, the highest manifestation of being is form, since for Aristotle, the “existence” of being was imperceptible and outside the philosophical “system” of cognition, for it concerned the “whole” of reality and could not be explained.

WHAT IS THE RELATION OF POTENCY TO ACT? In a real being the aspect of being called act possesses: (a) primacy in cognition, since only actual reality causes the process of cognition; (b) primacy in being, for only an actual existing being can be a reason for change or motion, namely for all that is expressed in the potency of being. Potency is the reason for everything in being that is associated with a state of imperfection, incompleteness, and multiplication; whenever the problem of explaining contingent and potential-dynamic reality arises, we cannot forget in our explanation potency in being as the factor that “causes” imperfection and limits the states of act.

Keeping in mind the basic “functions” of act and potency in being, we should be aware that potency and act are essentially ordered to each other in one being, and that they are always found in the same category of being, and therefore we know the nature of a potency in being by the act that is elicited from the potency. From our knowledge of act in being, we may infer something about the nature of the potency that is joined with the act by necessity. This has a special application in the study of man’s nature. Man’s biological and psychic acts can reveal his nature. Act and potency are two states of the same being, and as they are essentially ordered to each other, they create only one (essentially one) real being. The unity of a being is interchangeable with the being itself because in one being there can be only one act of being that has the possibility of actualizing many potencies of being. The unity of being is determined only by the act of being. Of course that which is an act of being in a “lower” order may at the same time be related as a potency to an act of being in a “higher” order. This primarily concerns the relation of potency and act under the aspect of the content or essence of being, where form is act in relation to matter, and form is always a potency in relation to the being’s act of existence (which constitutes being), for only “under” the act of existence can the content of the essence be organized. Without the being’s act of existence, none of the contents would be real or have any value in being; it is obvious that from two acts of being and two potencies without act there is not one being, since one potency added to another does not create a being or, by the same token, the unity of a being. The existence of the Being who is only pure act is possible and necessary. This is the Absolute—God. On the other hand, it would be a contradiction if a pure potency existed in itself without an act. Therefore prime matter conceived as pure potency cannot exist independently anywhere, but always exists in connection with some act.

The connection of potency and act in action is an important matter. An analysis of the action of contingent beings shows that an act is always the reason for the realization of an action in which we may observe the linking of potency and act. Aristotle observed that everything that is subject to motion (change, action), and so “everything that is generated, is generated from something, and by something” (Met., 1049 b 24); the expression “by something" should be specially emphasized in the Aristotelian adage “omne quod movetur ab alio movetur” (“Whatever is moved is moved by something else”), which was refined by Saint Thomas: “nihil reducitur de potentia in actum nisi per ens in actu” (S. th., I-II, q. 2, a. 2) (“nothing can be reduced from potency to act except by a being in act”). As we consider the motion and change in general terms, we may emphasize the necessity of act as the reason of being for “motion”: “moveri enim nihil aliud est, quam reducere de potentia in actum” (ibid., I, q. 2, a. 3) (“to be moved is nothing other than to be reduced from potency to act”).

The problem of action is nothing other than the problem of the actualization of potency. We know that the relation of potency to act is a relation, and we may provide a rational justification for this relation with the help of the principle of non-contradiction when we oppose act to potency as non-act. Our reasoning will proceed in the same way as when we think about non-contradiction: “being is not non-being”, “act is not non-act.”. We can expression a being’s potency as opposed to act in the form of the principle of non-contradiction, and then the necessity of act in motion and action will become very apparent. Act is the “reason of being” for action and the continuation of action. On the basis of the necessity of act as the reason of being in action or motion, there appears the necessity of the ultimate Pure Act—the Absolute as the sufficient ultimate reason for action. From the understanding of the motion of action that realizes potency by act, it follows that a being acts insofar as it is in act, and that it undergoes and receives action in itself insofar as it is in potency: “omne agit secundum quod est in act, patitur autem secundum quod est in potentia.” All real potencies of being are ordered to their actualization: “frustra est potentia, quae non traditur in actum” (“a potentcy would be futilte that did not pass into act”).

In the history of the reception of the Aristotelian theory of act and potency, which was richly developed by Thomas Aquinas, there were modifications of this theory in various systems that were applied to the conception being and knowledge. Plotinus in his Enneades [II, 4, and IV, 3) modified the theory of act and potency in the context of his conception of matter (υλη) and the relation of the soul to its faculties for action. J.Duns Scotus and F. Suarez made far-reaching modifications to the Aristotelian theory. They both had a great influence on how philosophy was conceived in scholasticism and neoscholasticism. Each introduced new distinctions in his philosophical system, e.g., Duns Scotus introduced the “formal difference”, and Suarez introduced the “physical” and “metaphysical” difference, which was a consequence of the epistemologization of metaphysics and influenced a different understanding of being.

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Mieczysław A. Krąpiec

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