"Among all human pursuits", Thomas Aquinas wrote, "the pursuit of wisdom is more perfect, more noble, more useful, and more full of joy."1 With wisdom as his goal, Aquinas’s life can be viewed as passing through three periods: first, the development of wisdom; second, the construction of wisdom; third, the final touches of wisdom.

LIFE2 AND WORKS3

Development (c. 1225-1259). Aquinas was born of a noble family in 1225 at the castle of Roccasecca near Naples. After his education by the Benedictines at Monte Cassino, he went to the University of Naples for his arts studies. At Naples, he joined the Dominicans and studied at the University of Paris and later at Cologne under Albert the Great, who acquainted him with Aristotelianism and Neo-Platonism. Returning to Paris after his ordination to the priesthood, he did graduate studies and lectured on Peter the Lombard’s Sentences at the University of Paris. His originality was manifested at this early time in his Writings upon the Four Books of the Sentences, and in two significant works: On Being and Essence4 which distinguishes between created essence and existence, and On the Principles of Nature5 which stresses the pure potentiality of prime matter.

During his first Paris professorship (1256-1259), the Master of Theology lectured on the Bible and resolved disputed questions which are articulated in his treatise On Truth6 and the Quodlibetales.7 He also developed his most extensive and penetrating study of the hierarchy of the sciences and their method in Exposition of Boethius’ On the Trinity8 and his notion of participation in Exposition of Boethius’ On the Weeks.9 As Augustinian, Neoplatonic, and Aristotelian ideas meshed in the early writings of Aquinas, they gradually assumed a new form.

- Construction (1259-1271). As Aquinas approached the high noon of his reflective powers, he systematically constructed his basic insights into a new synthesis. Returning to Italy, he taught at Anagni, Orvieto and Viterbo, continuing work begun in Paris on the Summa against the Gentiles (Summa contra Gentiles)10 and making his first attempt at a commentary on a Neoplatonic work in the Exposition of Dionysius on the Divine Names.11 He fused Christian and non-Christian traditions on God, the world and man, into a vast and profound synthesis in the Summa of Theology (Summa Theologiae.12 In Disputed Questions on the Power of God,13 he defined the relationship between God and creatures in terms of existential act.

During his second term (1269-1272) of teaching at the University of Paris, Aquinas defended the mendicant orders in his opusculum On the Perfection of the Spiritual Life,14 opposed Siger of Brabant, the Parisian Averroist, in his treatise On the Unity of the Intellect,15 and replied to Augustinian traditionalists in his work On the Eternity of the World, against the Complainers.16 Equipped with more authentic translations of Aristotle’s writings by William of Moerbeke, Aquinas composed detailed commentaries on the Aristotelian corpus.17 He also wrote scriptural expositions, theological elaborations in the Disputed Questions and Quodlibetal Questions,18 and more philosophical investigations in his work On the Books Concerning Causes and his incomplete Treatise on Separate Substances.19

Final Period (1271-1274). In the last period, Aquinas put some final touches to his architectonic vision. Appointed master of theology at the Dominican house of studies associated with the University of Naples, he lectured on the Psalms, commented on Aristotle’s works, and unexpectedly halted work on the Summa of Theology with the words: "I am unable to do it . . . Everything that I have written seems like chaff to me, in comparison with the things that I have been and that have been revealed to me."20 On the way to the second Council of Lyons, he fell ill and died on March 7, 1274 at the Cistercian Abbey of Fossanuova.

In probing the relation of faith and reason, Aquinas opposed the pietistic tendency to suppress philosophy in favor of religion and also the Latin Averroist rationalism which divorced philosophy from faith. Under the influence of Moses Maimonides’ Guide for the Perplexed, he endeavored to distinguish and correlate the dimensions of reason and faith within a unified vision. First, he would have to determine the meaning of faith and knowledge.21

- Philosophy and Theology. With a clear idea of the relationship between belief and knowledge, Aquinas could come to grips with the germane question of the connection between Christian theology and philosophy. Since "the philosophical sciences deal with all parts of reality even with God," and "Aristotle refers to one department of philosophy as theology or the divine science,"22 Aquinas asked whether there was need "for another kind of education to be admitted or entertained."23 Additional teaching from divine revelation and Christian theology seems superfluous, since God, men and the world "lying within range of reason yield well enough to scientific and philosophical treatment."24

If the necessity of revelation is granted, there arises the problem of associating philosophy and Christianity without impairing the integrity of either science. On the one hand, Anselm’s theologism tended to rationalize the object of faith so as to render it scientifically demonstrable, thereby making theology as faith seeking an understanding, appear unnecessary.25 On the other hand, to accept metaphysical truths on faith without a rational demonstration would make a distinct philosophical science superfluous. Aquinas was intent on preserving the purity of each science in their correlation.

Latin Averroists set philosophy and revealed theology at loggerheads by opposing rational conclusions which they accepted as Christians. Following Averroes, they reasoned to the eternity of the world and at the same time believed in the temporality of creation. If "what is rationally necessary is thereby necessarily true," these Averroists were following "a doctrine of twofold truth, . . . maintaining as simultaneously true two sets of contradictory propositions."26 Aquinas wanted to avoid the Scylla of Anselm’s theologism and the Charybdis of Siger of Brabant’s Averroistic philosophism.

Within the framework of faith and reason, Aquinas reflected on the most basic metaphysical problem of the meaning of reality. Reality had been viewed in different ways by philosophers: as being by Aristotle, as good by Plato, as unity by Plotinus, as truth by Augustine, and as essence by Avicenna.27 Aquinas’ decision about the core of reality and its relation to the totality of things would have to respect the insights of his illustrious predecessors so as to guarantee progress in the growth of metaphysics. The validity of his concept of reality would be tested by its success in explaining the traditional problems of unity and multiplicity, truth and falsity, good and evil.

Only by determining the relation between being and unity would Aquinas be able to deal effectively with the problem of whether and how many things derive from a single cause. According to Avicenna, one simple divine cause can produce necessarily but one effect; and hierarchical causes, necessarily originating from the first cause, successively produce one effect each.28 For Aquinas, Avicenna’s explanation did not make adequate provision for the pre-existence of plurality in the simplicity of the divine intelligence, and its procession from God by way of knowledge and freedom.

- Truth. Aquinas investigated the problem of truth within the context of unity and being.29 How can truth be related to being, if, as Aristotle says, "true and false are not in things but in the mind"?30 If truth is only in the mind, then whatever appears to each person — even contradictory views — is true.31 To overcome the relativity of truth, Aquinas found it necessary to show how a spiritual intellectual soul can understand a material thing. How can forms which, according to Aristotle, are understood by abstraction from matter, provide objective knowledge of reality where they exist with matter?32 Furthermore, if the intelligible likeness abstracted from things is that which is understood by the intellect, then things themselves, it seems, are not what is actually known.33

At the outset, Aquinas confronted objections to proving God’s existence from those who were impressed by its self-evidence. If "as Damascene says when beginning his book, `the awareness that God exists is implanted by nature in everybody,’"34 and if the word "God" which signifies "that than which nothing greater can be meant" implies his existence in fact as well as in thought,35 then all proof of his existence is superfluous. If God’s existence is not self-evident, then it must be demonstrated from effects in the world. But "it seems that everything we observe in this world can be fully accounted for by other causes, without assuming a God. Thus natural effects are explained by natural causes, and contrived effects by human reasoning and will."36 In a self-explanatory world, there is no need to suppose that a God exists.

Although Aquinas agreed with Dionysius the pseudo-Areopagite that "we cannot know what God is, but only what he is not,"37 he rejected the Neo-Platonist’s explanation of this negative knowledge which placed the divine One above being to which human reason is limited. To avoid agnosticism while holding the unknowability of God’s essence, Aquinas had to explain how the mind can rise from the experience of sensible things to a positive knowledge of God and can affirm that he is being, unity, and truth.38

If the divine cause of the world and its causal action is eternal, Aquinas wondered whether the world as its effect also always existed.39 Latin Averroists, on the one hand, reasoning against the Aristotelian background of the eternal principles of imperishable forms and ingenerable matter, concluded that the world is created from eternity. Bonaventure, on the other than, working within the Augustinian framework which identified eternity with God, affirmed that the universe is created in time. As a Christian theologian, Aquinas was concerned with how the eternity of the universe could be reconciled with the biblical teaching that "in the beginning God created the heavens and the earth."40

Aquinas intended to go beyond Plato’s and Aristotle’s explanation of the origin and notion of things in their class characteristics to account for the cause of their whole being, their complete substance.41 However, if God created the whole universe, how can he be exonerated from willing the evil of defective and corruptible beings,42 unless there is a Manichaean principle of evil, as the Albigensians held?

Investigation of the world throws some light on man’s nature, but there still remains the peculiarly human question of his unity and the duality of soul and body. On the one hand, the Platonic conception of man as a soul using a body ensures the uniqueness and immortality of the soul to the detriment of the body’s significance. On the other, Aristotle’s hylomorphic theory guarantees the substantial unity of soul and body but makes it difficult to explain the subsistence and immortality of the soul apart from the body which is in potency to another form.43

Aquinas encountered the problem of human freedom in his attempt to reconcile the Augustinian view of freedom in man’s relation to God and the Greco-Arabian conception of necessity and order in the universe.44 On the part of God, how is it possible for divine goodness which Neo-Platonists insist naturally and necessarily diffuses itself, to freely communicate its likeness to other beings?45 If, as analysis reveals, man’s will is moved by objects outside himself, how can he act voluntarily, since that is voluntary which has its principle within itself, as Gregory of Nyssa, Damascene and Aristotle declare"?46 Briefly, can choice be determined and free?

Working within the context of freedom and necessity, Aquinas investigated the moral problem of good and evil. If the will is somehow determined and, as Aristotle believed, desires only good, how is moral evil possible?47 As master of its actions, how can the will be governed by laws which prescribe its end? Men more or less agree on the most general abstract principle of conduct, for example, "do good and avoid evil," but how can they be sure of what is good and reasonable in concrete situations?

Aquinas encountered issues about God, the world, and man in view of his basic theme of being as existence,48 thereby radically differentiating himself from Aristotle’s conception of being as form. Existential act is the fundamental principle both of being and becoming. It constitutes the reality of the world as a dynamic principle that expresses itself in the essence it grounds. "The most perfect thing of all is to exist, for everything else is potential compared to existence. Nothing achieves actuality except it exist, and the act of existing is therefore the ultimate actuality of everything and even of every form."49 Becoming is the realization of form which as potency intrinsically depends on existential act which it receives. Existence is the key to understanding being as act. The highest reality towards which all else is oriented is no longer a passive essence — as Aristotle’s form, Plotinus’ unity, Augustine’s truth — but a dynamic pure existential act.50

Similarly, the source of action in the world is the act of to be of concrete things: "From the very fact that something actually is, it is active."51 Beings operate only insofar as they are, or possess their own act of being, the primary principle of their energy. The activity of a being is the unfolding in time of its basic existential act by which it is. In virtue of this actuality at the core of their being, things exist in view of their acts.52 Operation is the ultimate perfection of existents.53

Aquinas viewed reason and faith as two complementary approaches of a single Christian vision of reality in its totality. Faith, an assent of the mind under the influence of the will to truths revealed by God, formally differs from pure reason which of its own power grasps truth as it presents itself. Their distinction is evident from the fact that "it is impossible that one and the same thing (or aspect of a thing) should be believed and seen by the same person. . . ."54 Faith and reason reach different aspects even of the same object. For example, God can be known as the prime mover by rational demonstration, and at the same time be believed as the Trinity of persons by faith.55 When an object of rational knowledge is resolved into first principles, it is removed by this very fact from the domain of faith.56 Faith intimately completes reason in its concern for truths exceeding its natural capacity. Although, for example, God’s existence and oneness are rationally demonstrable, his infinite essence which transcends finite understanding is accessible to faith.57

- Complementarity. Since "man is directed to God as to an end that surpasses the grasp of his reason,"58 he needs faith to recognize that truth and strive towards that supernatural goal. "Hence, it was necessary for our welfare that divine truths surpassing reason should be signified to us through divine revelation,"59 and accepted on faith. Considering the limitations of the human condition, rationally knowable truths concerning God and the soul can and even need to be revealed. Without revelation, "the rational truth about God would have appeared only to a few, and even so after a long time and mixed with many mistakes; whereas on knowing this depends our whole welfare, which is God."60 God’s revelation enables even wise men to overcome doubt and error and to acquire certitude concerning natural truths or "preambles to faith."61 Faith complements reason.

As faith aids reason, so reason contributes in four ways to faith seeking an understanding of itself in sacred theology.62 First, as a propaedeutic, reason philosophically demonstrates the preambles to faith, for example, the existence of God.63 Second, as a guardian, it "refutes statements against the faith, either by showing that they are false, or by showing that they are not necessarily true."64 Third, with the help of philosophical concepts, reason deduces theological conclusions from revealed principles accepted on faith. Fourth, it explains theological conclusions in terms of sensible analogies and arguments of fittingness to show the reasonableness of revealed truths.65

The task of philosophy is to study the nature of "creatures in themselves" to come to "the knowledge of God," whereas that of theology is to consider their "relation to God" as their origin and goal.66 Purely philosophical conclusions about the nature of things, without losing their rational character, can be ordered towards an essentially theological end.67 While collaborating on common questions, philosophy and theology remain radically distinct in their principles of demonstration. Whereas philosophic reasoning begins with the self-evident principles of natural intelligence, investigates the essence of things, and argues to God as their first cause, theological reasoning starts with the articles of faith, and reflects on God’s revelation of himself and his relation to creatures.68

- Science. Aquinas defined his philosophico-theological method in terms of science conceived in its strict Aristotelian sense as certain and evident knowledge which reason demonstrates about things.69 As a result of these demonstrative acts, the mind develops an intellectual habit of thinking effectively in a definite way, and moving steadfastly towards truth. Theoretic reason aims to know truth by the three intellectual virtues of understanding, science and wisdom. Understanding grasps first principles; science demonstratively draws conclusions from principles; and wisdom demonstrates from the highest and widest principles. Practical reason activates truth by the virtues of prudence directing man’s doings to secure the ends of life, and of art ensuring that the things man produces are well made.

Aquinas divided the speculative sciences according to the aspect of reality that each attains by abstraction from things. For example, being as the proper subject of metaphysics differentiates it from other sciences.70 Following Aristotle, Aquinas distinguished the abstraction of the human mind’s first operation simply apprehending "what a thing is" from its second operation of judgment which "joins and divides" the intelligible essence by affirming and denying that and how something is or is not.71 Whereas natural philosophy and mathematics attain their proper subjects through apprehensive abstraction of objects which cannot exist in reality without other things, metaphysics reaches its object by the separation through a negative judgment affirming that being is not necessarily linked to matter nor to any of its conditions. In such a judgment based on knowledge of non material reality, the intellect considers being apart from all matter and declares that to be is not, as such, material.72

- Natural philosophy. The natural philosopher abstracts a whole from its parts or from its individuating notes which are really together in things; it considers, not this form and that matter, but form and matter as a whole — what is universal and necessary in corporeal things, what is essential in a nature to the disregard of what is incidental to it.73 With his rational method, the physical philosopher analyzes the constantly changing manifold of sense data to demonstrate from their effects the efficient and final causes, and to discover the nature and interrelationships of things.74 The rational approach of natural philosophy terminates "in senses with the result that we judge of natural beings as the senses manifest them. . . ."75 Sense experience is the final court of appeal for the veracity of its scientific judgments. Natural science sometimes reasons to true demonstrations, whereas in other cases it is restricted to "suppositions," which explain sensible appearances without being necessarily true, as with the Ptolemaic theory of astronomy.76

- Mathematics. Mathematics abstracts the form of quantity from the sensible thing,77 and deduces, by way of formal causality, conclusions from definitions and principles. For instance, a certain property of a triangle is shown to follow from its very definition.78 Because mathematics abstracts from changing sensible qualities, it is more exact and certain than natural philosophy.79 Since the mathematician’s judgments concerning geometrical entities "terminate in the imagination and not in the senses,"80 his scientific conclusions are directly verified by an appeal to the imagination.

- Metaphysics. Metaphysics goes beyond physical and mathematical abstraction to consider being as being,81 such of its properties as goodness and truth, and God, the first cause.82 Now being and its properties can exist in spiritual beings separate from matter.83 The metaphysician recognizes that spiritual beings actually exist or can exist without matter in view of a negative judgment which denies that being is necessarily bound up with material conditions. The judgment that being as such is not the same as form, as well as matter, implies that the mind has gone beyond being as essence and affirmed being in its existential character simply insofar as it is.84

The metaphysical method is uniquely intellectual, because it begins with insight into first principles, contemplates purely intelligible objects of metaphysics which are separated from material conditions, and terminates in the intelligible aspect of things by judging in the light of evidence revealed by the intellect.85 The human mind can attain a supreme synthesis in the metaphysical intuition of the multitude of truths in the unity of simple principles. "It is distinctive of reason to disperse itself in the consideration of many things and, then to gather one simple truth from them."86 The analytic movement of reason in other sciences finds its ultimate term in the metaphysical synthesis of objects in view of the universal notion of being and of God as the first cause of all beings. Because of the profundity of its insight and the unity of its ideas, Aquinas held metaphysics as the highest science.

Within a philosophico-religious framework Aquinas developed his thematic ideas under the influence of Aristotelian and Augustinian thought. He evaluated the positions of other thinkers, not according to the argument from human authority, which he regarded as generally the weakest of all proofs in philosophy, but in view "of the reasoning of what is stated."87

In the tradition of Augustine, Aquinas philosophized under the influence of faith as freely and rationally as Plato or Aristotle. Impressed by Aristotle’s insights and Albert the Great’s scientific reflections, he recognized the power of natural reason to follow its own method and principles to reach truth. He adopted Aristotle’s method and division of the speculative sciences and added to Boethius’ distinction of the sciences in terms of objects by defining the cognitional acts which grasp the different objects. As a consequence, the intellect, though passive insofar as it is determined by forms in the world, is shown to play an essential role in the abstractive determination of the subjects of the sciences.88 What is significant in the maturing of Aquinas’ mind is his recognition that being is constituted the proper subject of metaphysics, not through the abstractive apprehension of essence which is required for Aristotle’s philosophy of form, but through the affirmation of existence and separation in judgment.89

In his explanation of the relation between God and creatures, Aquinas used Aristotle’s concept of form as the point of departure for deepening his notion of being in terms of existential act. In his notion of being as existence he was decisively influenced by Boethius who distinguished between the individual and the form whereby the substance is,90 and by the Moslem philosophers who disclosed that existence is not included in essence but must somehow be added thereto. Alfarabi conceived existence as an accessory accident of essence, Avicenna regarded it as a property of essence, and Averroes viewed it as substance.

Aquinas went further and located existence at the very core of being as the act of all acts, "The existential act of being (esse) is the most intimate element in anything, and the most profound element in all things, because it is like a form in regard to all that is in the thing."91

Aquinas synthesized his insight into the existential actuality of Aristotelian being with the Platonic theory of participation to explain the plurality and unity of reality.92 He radically transformed Plato’s participation of things in ideas as their principle of intelligibility, into a participation of creatures in one supreme being, their source of reality. He incorporated the basic insights of previous philosophers in terms of existential participation: a being is one (Plotinus), true (Augustine), good (Plato), and beautiful (Pseudo-Dionysius), insofar as it shares in existence. In defining the participatory relationship between creatures and God, Aquinas followed Avicenna’s line of reasoning from participating beings whose essence is other than existence to the unparticipating simple being which is its own existence.93 In view of his notion of existential participation, Aquinas adopted Dionysius’ vision of creation as a hierarchy of beings whose summit is God, the pure act of divine existence.

- Substance and Accident. Within an Aristotelian context, Aquinas analyzed changing things into the nine accidents — as quality, quantity, and place — and substance which he defined as "that which is possessed of a nature such that it will exist of itself."94 Whereas the whole reality of the accidental determinations is "to-be-in"95 the supporting subject, the substance with its own act of to be exists by itself. Accidents participate in the existence of the substance.

- Matter and Form. Deeper reflection upon the concrete data of substantial change discloses that the element persisting through the transition is prime matter, the indeterminate substrata of change, and that the element which determines the character of a thing to be plant or animal and places it in its specific class, is the substantial form. "Evidently, then, essence embraces matter and form."96 Every corporeal substance is composed of matter and form. Following Aristotle, Aquinas defined prime matter as pure potentiality to every form, and form as the first act of a physical body, placing a body in its class and determining its essence. United in corporeal substances, matter shares in the form, as potency in act.

Aquinas saw no need of the Augustinian theory of seminal reasons in his concept of prime matter as pure potentiality, without act or form even in a germinal way.97 The agent so changes the dispositions of a corporeal substance that it develops an exigency for a new form which is educed out of the potentiality of matter. Aquinas also rejected the traditional theory of the plurality of forms with the argument that what is already constituted as substance by the first form, can be subsequently determined only by accidental forms.98

- Individuation. Aquinas agreed with Aristotle that individual substances, which alone actually exist, are classified in a determined species in virtue of their form. But to exist in a particular substance, form, which of itself is a universal element, needs to be individuated and numerically multiplied by matter. But matter of itself is pure potentiality without any determination. Aquinas, therefore, was compelled to include quantity along with matter in the principle of individuation. Form is individuated by "designated matter", or matter determined by quantitative dimensions.99 The principle of individuation, therefore, is matter as signed by quantitative determination which it receives from union with the form.

- Spirit. Within the framework of a hierarchic scale of being, Aquinas found it natural to posit the existence of angels. There would be a glaring gap between God, the uncreated pure spirit, and man, the created embodied spirit, if created pure spirits did not exist.100 Unlike Bonaventure’s application of the hylomorphic theory to angels, Aquinas argued that purely spiritual intelligences in the hierarchy of being must be completely immaterial with no exigency for quantity. Without matter, angels are not multiplied in the same specific class; rather each angel is an individual pure form which alone fulfills the capacity of its species. "While there is no composition of form and matter in angels, there is a composition of actuality and potency," of form and existence by which it subsists101 as contingent beings radically distinct from God.

- Existence. Going beyond Aristotle, Aquinas reasoned that substance is a being, not insofar as it is matter or form, but inasmuch as it has existence. Because matter has no existence of its own apart from some form,102 it cannot be the cause of the existence of substance. Although form substantially determines and specifies its matter, it is limited to making a being belong to a class.103 It is necessary to posit beyond the form by which a thing is such and such a being, the act of being by which the substance exists. "For if we say that in composites of matter and form the form is the principle of existence (principium essendi), it is because it achieves the substance whose act is the act-of-being (ipsum esse)."104 The substance exists only by reason of the act of being in which form participates as potency in act.

Since the form exists only in virtue of the existential act which makes it a real being, existence holds a radical primacy over essence. Existential act is the core of reality: "Existence is more intimately and profoundly interior to everything than anything else, since it informs all that is real."105 The act of being is the primordial principle in things, because it is "the ultimate actuality of everything else, even including forms. Its relation to other things therefore is not that of receiver to received, but of received to receiver."106 By integrating the Platonic doctrine of participation and the Aristotelian notion of being, Aquinas explained Dionysius’ vision of creation as a hierarchy of beings in terms of a graded sharing in existence. For Aquinas, metaphysics is the science of being as existential act.

- Unity. In view of his existential notion of reality, Aquinas conceived being as transcendentally one, true, good, and beautiful insofar as it exists. A being is one inasmuch as it is or shares in its single act of to be. In virtue of the undivided act of to be, being and unity are convertible: every being is one and whatever is undivided is being. Hence, "everything existing is one."107 Identity is a negation of divisibility.108 Plurality arises from the unity of a being in itself and its division from other beings. "Clearly then everything’s existence is grounded in indivision. And this is why things guard their unity as they do their existence."109 In this way, Aquinas incorporated unity, which Plotinus posited at the summit of reality, into his notion of being.

- Truth. Whereas Aristotle did not consider truth to be a property of being as such, since it is found in the mind and not in things,110 Aquinas referred it to being insofar as it is related to the mind. In this context, he concluded "truth is primarily in the intellect, and secondarily in things, by virtue of a relation to the intellect as to their origin."111 Truth resides formally in the intellect which, in knowing "its own conformity to the thing known, . . . judges that the thing corresponds to the form of the thing which it apprehends."112 Truth and being are interchangeable: every being is knowable by the intellect, and everything knowable by the intellect is a being.113 As with being and unity, being and truth are identical in reality, they differ only conceptually with truth adding the notion of knowability to being.114 In this analysis, therefore, Aquinas integrated truth, which Augustine sought as supreme reality, into his notion of being.

- Good. Aquinas also incorporated Plato’s central notion of good into his metaphysics of existential being. In view of Aristotle’s dictum that "good is what all things desire,"115 Aquinas reasoned that desirability follows from an object’s perfection and actuality which is achieved by existing.116 That is why "the Book of Causes says that `existence is the first thing created’,"117 and "Augustine says that inasmuch as we exist, we are good.’"118 Conversely, everything that exists is good. The same in reality, they differ in concept, with good adding the notion of desirability to being. Thus goodness is being conceived under the aspect of its perfection and desirableness.119 "Since good is what all thing desire, and this involves the idea of a goal, clearly being good involves being a goal."120 With St. Anbrose, Aquinas divided good into the worthy which is desirable in itself, the useful which is sought for some other thing, and the delightful which is appetible for its satisfaction.121

- Beauty. Beauty does not play a role comparable to the other properties in Thomistic metaphysics. In line with pseudo-Dionysius’ statement, "the good is esteemed beautiful," Aquinas grounded the identity of beauty with goodness in the form of a thing.122 Whereas goodness relates to form as fulfilling the appetite, beauty pertains to form as restful to apprehension. Hence, "we call a thing beautiful when it pleases the eye of the beholder."123 Beauty is that which pleases when seen. The three elements of beauty — integrity, due proportion, and clarity124 — are given by the form through which a beautiful thing has existence.

Aquinas explained the structure and relations of existing being in view of Aristotle’s fourfold division of causes: moving, formal, material and final. He integrated Augustine’s seminal reasons into the Aristotelian causes rather than as being in the material causes from the beginning of the world.125 Whereas Aristotle conceived efficient causality in terms of motion (hence, the Aristotelian designation ‘moving cause’), Aquinas, influenced by Avicenna’s notion of a creative cause giving actual existence, viewed God as the efficacious cause of existence as such and creatures as cause of a particular aspect of existence.126 Aquinas’ integration in terms of existence of the Platonic doctrine of participation and the Aristotelian notion of causality provided him with a metaphysical framework for reasoning from creatures to God and from God to creatures.127

He criticized Anselm’s so-called ‘ontological’ argument for illicitly proceeding from the idea of a being than which no greater can be thought to its existence in fact. It does not necessarily follow from the concept of the greatest conceivable being that such a being exists outside the mind. Anselm, no doubt, would respond to Aquinas, as he did to his comparative critic, Gaunilo, that the objection holds for all concepts except that of God. As the being than which no greater can be thought, God is not simply possible but a necessary being. He must exist in reality, otherwise he is not that being than which no greater can be thought. But Aquinas added that the human intellect has no direct intuition of God’s nature in the sense of discerning a priori the positive possibility of the supremely perfect being whose essence is to exist.128

- Self-Evident Propositon. Aquinas realized that the historical fact of atheism would not be possible were God’s existence immediately manifest to man. The fact that the atheist can affirm that "God does not exist," indicates that the proposition "God exists" is not self-evident to man. While the proposition, "God exists", is self-evident in itself inasmuch as God is his own existence, it is not self-evident to man who does not directly know what it is to be God and consequently cannot immediately predicate existence of God.129

B. Possibility of Proof. Here Thomas faces a number of difficulties. First to the challenge that if God’s existence is not immediately evident to human knowledge, how can it ever be uncovered he responds that "faith presupposes natural knowledge"130 of God’s existence. Second, to the question how can natural reason discern what is not evident except to faith, or overcome its restriction to knowing only what God is not, he responds by insisting that knowing what God does not presuppose knowing that he exists. And third to the difficulty of proceeding disproportionately from finite things to an infinite source he counters that limited effects "can serve to demonstrate that God exists, even though they cannot help us to know him comprehensively for what he is."131 It is possible to demonstrate the fact of God’s existence without knowing why it is true by reasoning "from effects evident to us" in immediate experience to the existence of their cause.132

C. Demonstration. Aquinas presented five ways of demonstrating God’s existence. Their metaphysical core is the central principle of his notion of participation, namely, that where the essence of a being is potency to esse as act (composit being) its actual existence cannot be explained by itself, but only by another being whose essence is identically its existence (simple being). There are five indices of the state of being a composite being, namely, motion, causality, contingency, perfection and order.133

- Proof from Motion. Like Maimonides and Albert the Great, Aquinas adopted Aristotle’s proof from motion or change,134 which essentially entails potency. Anything in process of change is being moved by something else, because nothing can be reduced from potency to act or from passivity or mere possibility to activity or actualization except by another in act. If that other is itself moved, it must be actuated by yet another agent. An infinite series of movers and moved things, taken as a whole, must also be moved, and hence requires a cause which is not so moved or subject to potency in order to reduce it from potentiality to actuality. Therefore, there must be "some first cause of change not itself being changed by anything, and this is what everybody understands by God."135

- Proof from Causality. The second proof, used by Avicenna and Albert, and traceable to Aristotle, starts from the series of efficient causes, each caused by, or dependent upon another in order to cause. This argument turns on things as producing rather than on their undergoing change as in the first proof. In an ordered series of efficient causes, there could be no last cause nor intermediate one without some first cause which is not itself caused or subject to potency. To this "everyone gives the name `God’."136

- Proof from Contingency. Like Maimonides,137 Aquinas adopted Avicenna’s proof from the contingency of things in the world. In this demonstration, he went beyond the changing, causal character of things, to focus on the contingency of their being. Observation shows that things spring up and perish in time, indicating that while they can exist they are not bound to be. Even if one were to proceed beyond changing things to an order of unchanging but limited beings the question remains whether such beings are necessary of themselves or of another. If the latter "one is forced therefore to suppose something which must be, and owes this to no other than itself; indeed it itself is the cause that other things must be."138

- Proof from Degrees of Perfection. The fourth argument from the perfection of things penetrates deeper into the metaphysical structure of the world. Here Aquinas synthesized some observations in Aristotle with the ideas of Plato, Augustine and Anselm.139 Observable things show a gradation in the sense that they are more or less good, more or less true, more or less being, and so on. "But such comparative terms describe varying degrees of approximation to a superlative."140 The truest and best and most noble of things, the most fully in being, causes in other things the perfections they have, for participated being which has more or less of perfection as limited must be constituted of a distinct essence which stands as a limiting potency for existence. Hence, its limited perfection must be received from a simple and unlimited being which is perfection in its purest state. The most perfect existent is called "God".

- Proof from Order. The fifth argument from the orderedness of inorganic bodies turns on the principle that operations cannot be directed to ends except by an intelligent cause. Observation reveals an orderedness in the cooperation of different things with contrary qualities and in the operation of individual objects for an end. The fact that their behavior hardly ever varies and practically always turns out well for the harmony of the world shows that they do not function haphazardly but rather tend to a goal. "Nothing however that lacks awareness tends to a goal, except under the direction of someone with awareness and with understanding,"141 as the arrow is guided by the archer. In the pattern of the prior four ways, however, such ordering, like moving, even if in an infinite series of final causes, is not causes is not except by something self-sufficient in ordering. This director is called "God".

- Positive Way (via affirmativa). Whereas negative names, such as "immutable", remove from the notion of God a characteristic incompatible with him as first cause, positive names such as existing, unity, truth, goodness, and life, are affirmatively predicated of God and signify something in God.155 For Aquinas, the opinion of Moses Maimonides that all names of God are negative predicates implies the affirmation of something existing in God. "The meaning of a negation always is founded in an affirmation," for "unless the human understanding knew something of God affirmatively, it could deny nothing of God. . . ."156 The statement that God is not a body implies the proposition that God is.

Aquinas also rejected the opinion of Alan of Lille (d. 1202) that the assertion "God is good" means nothing more than "God is the cause of all goodness." If such were the case, then consistency would dictate that God is body inasmuch as he is the cause of all bodies. To affirm that God is good means that goodness positively exists somehow in God. Hence, Aquinas concluded that "God is not good because he caused goodness, but rather goodness flows from him because he is good. As Augustine says, `Because he is good, we exist.’"142

For Aquinas, the positive predicates attributed to God imperfectly signify how God exists. The statement "God is good" implies what is predicated, but not how it is predicated. The word "goodness" which is affirmatively predicated of God, signifies a reality which involves no defect. Likewise, the formal notion of "to be" (esse), unity, truth, and wisdom, which do not necessarily imply any note of imperfection, "can be used literally of God."143

- Negative Way (via negativa). Because every limited effect experienced by man is unequal to its unlimited first cause, Aquinas emphasized under the influence of the neo-Platonist Pseudo-Dionysius that "we are unable to apprehend it (divine essence) by knowing what it is. Yet we are able to have some knowledge of it by knowing what it is not."144 He conceived this negative way as a process of successively removing (via remotionis) from the notion of God all the modes of finite existence that cannot belong to the divine being. Because "by its immensity, the divine substance surpasses every form that our intellect reaches,"145 it cannot be positively defined by genus and species, but must be negatively affirmed and negatively differentiated from the phenomena of our immediate experience.

- Negative Attributes. After reflecting on the data of empirical experience, the mind can progressively affirm that God who exists beyond sensible things as their ultimate cause is not material, because matter (or body) which is potentiality and participates in form cannot belong to God who must be "sheer actuality" and "essentially form."146 Nor is God composed of matter and form, substance and accident, essence and existence, for these components, involving the correlation of potency and act and the causation of the composite, cannot be found in God who is pure actuality "without qualification" and the uncaused "first cause".147 In positive terms, God is absolute simplicity.

God is not composed insofar as he is not limited as form is by matter, substance by accidents, and existence by essence, because his actuality is unrestricted and self-existing.148 Not circumscribed (in positive terms, "omnipresent"), his unlimited existence is not by power inasmuch as everything is subject to his power, by presence inasmuch as everything is naked and open to his gaze, and by substance inasmuch as he exists in everything causing their existence. . . ."149 As pure self-actuality, he is the fullness of perfection with no imperfection.150 Since God is pure self-actuality without any potentialities to be actualized, he does not need to move; he is not changeable.151 In virtue of his unchangeableness, God’s duration is not temporal, because in his immutable duration he exists eternally or all at once now without beginning or end.152

Words are predicated of God in an imperfect manner. They express realities in the limited way they are conceived by the human intellect and articulated in speech. It is not that man knows and talks about God from his experience of empirical things which only finitely resemble their first cause. It is the nature of metaphysics to develop the notion of being from which such limitations are removed as to what it is that is said. The problem which remains, however, is related to the limited character of the human mind itself and from which the mode even of its metaphysical expression cannot escape. "The reason why Dionysius says that such words are better denied of God is that what they signify does not belong to God in the same way that they signify it, but in a higher way."153

- Transcendence. In predicating these negative attributes of God, the mind affirms that God surpasses all sensible and intelligible things. That is why Aquinas affirmed that "neither the Catholic nor the pagan understands the nature of God as he is in himself. . . ."154

Words as wisdom and truth mean more of God than they signify of creatures. "The sentence (`God is living’) is used say that life does pre-exist in the source of all things, although in a higher way than we can understand or signify."157 Life and wisdom belong to God in supreme manner.

- Transcendental Predicates. Aquinas positively predicated of God being or existence and its transcendental properties of unity, truth, and goodness. He found Avicenna theologically ahead of Plato and Aristotle in affirming that God’s being is not other than his existence.158 God is being in the sense that his "existence is his essence"159 in contradistinction to creatures whose essence is really other than their existence which is received and limited. Hence, God is most appropriately named "Existence itself" (ipsum esse), or in the words spoken to Moses, "He who is" (Yahweh).160

Because God’s essence is to exist, he is supremely one in himself and distinguished from the multiplicity of creatures.161 Truth as conformity of mind and being "is verified most of all in God. For his being is not only conformity with his intellect, but is his very act of knowing. . . ."162 Because "God’s understanding is his being",163 he is supreme, original truth which measures all other being and truth. "Since it is as first source of everything not himself in a genus that God is good, he must be good in the most perfect manner possible."164 Goodness belongs essentially to God who alone is perfect existence and consequently supremely lovable in himself and the ultimate source and goal of creatures.

B. Analogy. In his concern for using words to mean more of God than they signify of creatures, Aquinas applied names to both, "neither univocally nor equivocally but analogically."165 On the one hand, if in the statement "God is good," the word "good" means univocally the same for God as it does for creatures, then God is reduced to the level of creatures — an unacceptable consequence. On the other hand, if empty of all significance God would have left the universe bereft of ability to relate to its source and goal.166

Words are used analogously of God and creatures according to a meaning that is more than verbal and less than specific or generic sameness. A meaning is common to different objects according to their relation to some third thing or to each other. As regards a third term, "we say that an animal is healthy as the subject of health, medicine is healthy as its cause, food as its preserver."167 This kind of analogy, however, is inadequate to explain the application of predicates such as being and goodness to God and creatures who in themselves and not by reason of a third thing are really related to God.

Since creatures are related to God as effects to their cause, meanings can be analogously predicated of them as between two sets of paired terms. In this analogical context, positive perfections, such as being, whose formal meaning does not necessarily imply imperfection, are affirmed first of God who is essentially existence, and secondarily of creatures who participate in existence. "When we say he (God) is good or wise we do not mean simply that he causes wisdom or goodness, but that he possesses these perfections transcendentally or eminently."168 What is meant by the names "existence" and "goodness" is affirmed originally of God and derivatively of creatures.169 The likeness of effects to their cause makes possible the predication of pure perfection to God and creatures in a similar sense, whereas the deficiency of this resemblance necessitates predicating it in a dissimilar meaning.

- Analogy of Proportion and Proportionality. To clarify his theory of analogical knowledge and language, Aquinas distinguished between "proportion" and "proportionality". According to the first kind of analogy, "there is a certain agreement that they have determinate distance between each other or some other relation to each other. . . ."170 Analogy of proportion is the similarity of a simple relation, for example, between 8 and 4. Being is analogically predicated of created substance and accident which resemble each other according to a simple proportion. However, being cannot be attributed to God and creatures in the same way, because unlike the real relation of created substance to accident, God is not dependent on creatures and not included in the definition of creature. Nevertheless, the fact that creatures are really related to God, makes it possible for the same term to be attributed analogously to both.

Analogy of proportionality involves "the agreement . . . between two related proportions. . . ."171 This is not the identity of a mathematical proportionality, as for example, 6 is to 3 as 4 is to 2, but the infinite distance from creature to God, from composit to simple being developed in the five ways above. Literally, as being is to creatures, so being is to God: the existence of a creature is to its creaturely essence, the existence of God is to the divine essence. No matter how much human knowledge progresses, it does not know how God exists in himself. "Indeed, this is the situation, for, while we know of God what he is not, what he is remains quite unknown."172 Man cannot know what it means for perfections to exist in God.

C. Intelligence. Intelligence and will, the noblest perfections of man, can be attributed to God by analogy with his creatures. Intelligence is a perfection of an immaterial spirit which can and should be predicated of God in a superlative way since he is a spirit who is infinite, eternal, and "immaterial in the highest degree. . . ."173 Since in God "intellect and what is known must be identical in every way,"174 he is completely present to himself and affirms himself perfectly. Unlike Aristotle’s self-enclosed divinity, Aquinas affirmed that in perfectly comprehending his power which is one with his being, God grasps all the effects to which his power extends. "Things other than himself he sees not in themselves but in himself, because his essence contains the likeness of things other than himself,"175 not only in their general characteristics but also in their individual reality.176 Eternally embracing the whole of time in an immovable present, God knows all possible177 and future contingents as actually present and realized.178

As a subjective mental modification, the idea cannot be plurality in God whose intellect is identical with his undivided essence without any possibility of receiving determinations or any sort of composition. The divine ideas are not really distinct modifications but together with God’s act of knowing they are identical with his simple essence and hence absolutely one. "God in his essence is the likeness of all things. Hence an idea in God is simply the divine essence."179

D. Will. Will is also a perfection which, removed from the limitations of creatures, can be predicated in the highest degree of God as identical with his simple being. Since "anything with a mind has a will, just as a thing with sensation has emotional appetite, . . . there must be a will in God because he has a mind."180 God primarily and necessarily wills his own being as the principal good apprehended by his intelligence, and in so doing, wills all other things insofar as they can participate in the divine goodness.181 With no need of perfection from creatures, God does not necessarily will other things. He wills unchangeably whatever changes he wills.182 Because a self-destructive contradiction, for example, a square circle, cannot share in resembling the divine being, it cannot fall within the scope of God’s will.

- Life and Beatitude. As "that Being, then, whose own nature is its act of knowledge" and willing, "which also does not have what belongs to it by nature determined for it by another," God is "the Being which has life in the highest degree."183 Fully conscious of the "plenitude in the good" he possesses, and complete "master of his actions," God is supremely happy.184 God is happiness, creatures have happiness.

The different attributes predicated of God give rise to the question of whether they are really distinct from one another. Since God is absolutely simple, his attributes, such as intelligence and will, are really identical with his divine essence. If this be so, what justification is there for speaking of them as though they were distinct? The distinction arises from the approach of human knowledge which, from the consideration of God’s effects as manifesting their cause, forms different concepts expressed in different names to describe the divine essence. What a finite and discursive intellect knows in composite and distinct concepts is, nonetheless, one simple divine reality. Inadequate and imperfect knowledge of God, to be sure, but true knowledge nonetheless.185

In searching for the origin of all things from the first cause, Aquinas asked not only about their motion, matter, and form, but about their very existence as such, not simply why they are this or that being but why they exist at all. Everything besides God exists not by its own essence, but by receiving existence from Him who exists of himself. Now to cause existence as such implies as the condition of its possibility no preexisting matter whatsoever from which the universe is made. This production of the whole of all ex nihilo, "the non-being which is nothing at all," is none other than "creation."186

Creator and creatures are closely related. The creature is really related to God upon whom it depends as the cause of its being. However, God has no real relation to the creature. If such a relation were in God as identical with his substance, he and creatures would form a totality within which he would necessarily depend on them for his existence. Such a consequence was unacceptable to Aquinas. Neither would he admit an accidental relation, as if God, pure act, could be potential in regard to any of Aristotle’s categories of accidents. Nothing can enter into composition with God who is absolute simplicity. The relation of God to creatures, according to Aquinas, is one of reason, a mental relation, attributed to God by the human intellect on the basis of the real relation of creatures to their creator.187

Because "properly speaking to create is to cause or produce the existence of things" and not simply to effect their form, it is "God’s action by reason of his existence, which is his very nature. . . ."188 Existence, the most universal and original of all effects, is the proper effect, not of a creature whose essence is receptive of existential act, but of "the first and most universal cause"189 who is the unlimited act of to be. All effects produced by finite power presuppose existence tout court which can be caused exclusively by the infinite power of God who alone can bridge the unlimited gap between nonexistence and existence.

Since God’s free will is not necessitated by any good beyond himself, no reason other than his own goodness and his own glory -- that is, the manifestation of this goodness -- can be assigned for his decision to share existence with creatures. "He alone is supremely generous, because he does not act for his own benefit but simply to give of his goodness."190 It was eminently fitting for pure existential act creatively to share its perfection.

While holding that philosophy can show the creation of the world from nothing, Aquinas believed that it cannot adduce reasons "demonstratively" proving the necessity of creation either in time or from eternity.191 Either way is possible in view of divine freedom and the contingency of creatures. As eternal, God might have created the world from eternity, thus making possible "an unlimited number of things" extending into the past.192 "There is no necessity for God to will an everlasting (or temporal) world. Rather the world exists just so long as God wills it, since its existence depends on his will as on its cause."193 As contingent, creatures can either exist or not exist, either from eternity or in time, depending on God’s will.

God is free to will from eternity that the world come to be in time, or that it have eternal duration. What philosophic reason can show to be possible, can be definitively known to be actual only from God’s self-revelation made to the believer of his eternal decision to create the world in time. "This therefore is held through revelation alone, and cannot be demonstrated."194

The world’s continuance no less than its origination depends on the creative efficacy of God. Although artifacts continue to exist after the artist’s work has ceased inasmuch as he simply alters matter by conferring on it a new form, it is a different case with finite nature. Every creature is essentially related to God as the sole source of its existence so that without his continuing present causality the universe would cease to exist. "The preservation of each and every thing depends on its cause. . . ."195

Because God is good, the world he created is itself good. Indeed, "the universe cannot be better, as things actually exist, because the order God has established among them, and in which the good of the universe consists, most befits them."196 However, since divine power is infinite and since every creature participating in perfection is limited, it is always possible for God freely to create another universe that shares more in perfection--a better world. Why God chose the present universe out of the infinite number of possible ones he could have created is his secret. An absolutely best possible universe, like an absolutely greatest number, is inconceivable.

Moral evil, however, the disorder of a creature’s free will, opposes the universal order within which free agents are orientated towards the divine good, and hence cannot be willed even incidentally by God without denying himself. God wills man’s freedom and tolerates his misuse of freedom for a greater good, namely the life of freedom itself. In this sense, "that whole composed of the universe of creatures is the better and more complete for including some things which can and do on occasion fall from goodness without God preventing it."197

Following Aristotle’s theory of hylomorphism, Aquinas viewed human beings as composites of matter and a rational form, standing between the angelic world of pure intellectual forms and corporeal creation which is composed of matter and mineral, plant or animal forms. The substantial form as the inner source of a living being’s self-motion and self-development, is called soul. Each human soul possesses "a complete act of existing in virtue of its own nature."198

- Unity. To explain how the human composite of body and soul with its multiple operations is a single subject, Aquinas, at first, seemed to lean towards the prevalent Augustinian theory of a plurality of forms. Though this theory accounts for the variety of human operations and the difference between matter endowed with a form of corporeity and the human soul with its own independent existence,199 it was rejected by Aquinas as inadequate to explain man’s substantial unity.

Adapting Aristotle’s hylomorphic theory in term of existence, Aquinas reasoned that one being can have but one existence, one existence can have but one essence, and one essence can have but one form. Man exists and operates as one subject insofar as he has one substantial form which also informs the matter and simultaneously confers on man being, corporeity, life, sense, and understanding. "The same act of existing that belongs to the soul is conferred on the body by the soul so that there is one act of existing for the whole composite."200 There is but one undivided human nature and one human subject.

Within the whole human composite matter needs the rational form to be a human body with living, sensory functions which belong to the one human subject. Likewise, the rational soul needs the body so that it intellectual power can grasp the meaning of things sensibly experienced and thus, find fulfillment of its vital, sensory, intellective capacities in the body. "It is for the good of the soul to be joined to the body and to understand by turning to sense images."201 While body and soul are co-constituents by which man is and operates, it is the individual human subject that properly exists and functions.202

In his concern for the manifold functions of the one human being. Aquinas held a real distinction between the essence of the soul and its powers, and between the powers themselves. Because the rational form is not identical with its existential act, it does not essentially exist or function but rather is in potentiality to operation by powers which "are distinguished in terms of their acts and objects."203 Since these powers originate in an orderly way (vegetative, sensitive, intellective) from the one soul and participate in its single existential act, they are "an ordered relationship" in the one human existent.204 In this hierarchy, the higher the power the wider and more comprehensive its object; for example, the intellect has as its object, not only sensible bodies perceived by the sensitive power, but being in general. By reflecting upon man’s functions and their proper objects, Aquinas distinguished in Aristotelian fashion the soul’s vegetative, sensitive, appetitive, locomotive, and intellective powers of acting.205

- Vegetative Powers. In common with other living things, man has the vegetative powers of nutrition, growth, and generation which transcend inorganic physical forces. These powers "do not exist without the body, for they are performed through bodily organs."206 Whereas the object of the vegetative power is simply the body of the sentient subject, that of the sensitive faculty is every sensible body.

- Sensation. Man shares with animals the five external senses of sight, hearing, smell, taste, touch, distinguished according to their respective formal objects of color, sound, odor, taste, pressure. Sense activity involves a "spiritual change when the form of color is in the eye, which does not become the color it sees."207 Unlike Augustine who thought sensation belonged simply to the soul using a body, Aquinas held that the sensory faculties of the soul belong to the whole human subject in such a way that they cannot operate without a bodily organ.

Sensible objects perceived by the external senses evoke a response in the internal senses: common sense, imagination, instinct, and memory. Common sense distinguishes, compares, and combines different sense data, as it perceives the various functions of the senses. The data collated by common sense is represented and reconstructed by the imagination which conserves the forms grasped by the senses. "What we call natural instinct in other animals in man we call cogitation, which . . . compares individual intentions" in view of their beneficiality or harmfulness, "the way the reasoning intellect compares universal intentions."208 As regards sense memory, man not only shares with other animals the "sudden recollection of things past," but also reminisces or searches in a "quasi-syllogistic" way among memories for the one desired.209

The objects perceived by sensation are desired as an end by the sense appetite and attained by movement in place. "By this (appetitive) power an animal seeks after what is knows, not merely going where inclination leads."210

- Intellect. Deepening his analysis of human subjectivity, Aquinas sees it able to reflect upon being in general, the universal object, and reasoned to the intellect as a faculty whose operation intrinsically transcends the sense experience of particular objects. Unlike sensory powers, the rational faculty belongs to the soul as such, functions without intrinsic dependence on a bodily organ, and remains operative in the soul even when it is separated from the body. In its function of remembering, the intellect transcends sensory memory of particular objects as past by conserving and recalling concepts. The speculative and practical intellects are but one intellectual power, for both concern truth with the latter directing "that known truth towards action."211

- Individual Intellect. In his concern for the uniqueness of each person, Aquinas rejected Averroes’ theory of the intellect (both the active and passive intellect) as a substance distinct from the human soul and common to all men. If there were one intellect for all men, it would be the subject of knowledge, functioning independently of the individual and understanding without the help of the individual’s senses and imagination. However, the fact is that the individual is conscious that he knows, pursues intellectual activity at will, needs sense experience for intellectual operations, and enjoys intellectual capacities and ideas that differ from another’s. These facts can be explained adequately only by the presence of an individual intellectual substance informing the body of each person. The uniqueness of each human being "following upon the unity of its form" which is the "intellective soul".212 Indeed without such there could be no personal responsibility or destiny.

- Appetition. Within the ceaselessly changing universe, man finds himself restless and active. Reflecting on man’s natural inclinations, Aquinas disclosed three kinds of appetites. First, man has certain natural inclinations in common with physical substances, for example, the tendency of heavy bodies to fall downward. Second, he shares sense appetites with animals: "desire" (concupiscibilis) drives towards "what pleases the senses and avoids what hurts them", and "aggressiveness" (irascibilis) resists whatever threatens its pleasure and brings danger" by striving to overcome and rise above the difficulties.213 Love and hostility, desire and aversion, pleasure and pain, are emotions of the inclination of desire; hope and desire, courage and fear, and anger, are passions of the aggressive drive.

- Will. Third, in conjunction with his power of reason, man possesses a rational appetite or will.214 The will "though it bears on objects . . . as concrete particulars, nevertheless attains in them a universal object of reason, desiring a thing precisely because it is good." Motivated by good as such, the will necessarily desires happiness. Such necessity is not imposed from without by violence (necessity of coercion), but is a necessity of nature (natural necessity proceeding from the nature of the will).

"Since the will’s potential is to total and perfect good, that potential cannot be exhausted by any particular good, and so it cannot be moved necessarily by it."216 Although the will’s drive towards good as such implicitly orientates man towards God as the supreme good, this does not mean that man must explicitly desire God as his ultimate goal. Since man encounters only particular goods to which his will is contingently related, he does not see clearly and steadfastly the connection between happiness and God, and consequently does not necessarily will God.

"Free will" signifies, not a power different from the will, but the same faculty as principle of free choice of means to the end. Whereas the will necessarily desires universal good as its final end, it freely chooses particular goods as means to the end: it is able to choose or not to choose, to choose one good rather than another. Unlike the animal whose natural instinct determines its "judgment," for example, a sheep’s "judging" that the wolf is to be avoided, man judges that some good is to be attained or some evil to be avoided by a free act of his intelligence, a decisive judgment. Since "particular actions are contingent . . . reason’s judgment is open to various possibilities, not fixed to one. It is because man is rational that such decisions must needs be free."217

The sensitive soul of the brute intrinsically depends on bodily organs for all its operations and corrupts with the corruption of the body. In contrast, the intellectual soul functions intrinsically independent of the body and subsists in a spiritual and consequently incorruptible state. The mind’s need of the body arises, not from its own intrinsic immaterial activity which is exercised without an organ, but from its natural object in this life with the soul conjoined to a body. Since the intellectual soul "has its own activity in which the body takes no intrinsic part,"218 apprehending "objects universal and incorruptible as such,"219 it must be subsistent and incorruptible.

Furthermore, because "man has an intellectual apprehension of existence as such, and not only of existence here and now as the brutes have,"220 he naturally desires to persist in being not with a temporal limit, but perpetually. Implanted by the author of nature, this desire cannot be in vain. This argument that the natural desire for immortality ought to be fulfilled is based on the previous proof that it is possible of achievement in a spiritual soul.

Though the human soul alone is incomplete in essence, comprised as it is with the body in man’s nature, it is complete as far as its existence is concerned. Possessing its own existential act with no matter from which its form could be separated, the human soul subsists as a spiritual substance in its own right and naturally persists perpetually in being.221

In his affirmations about God, the world, and man, Aquinas critically reflected on the nature and truth of knowledge to lay an epistemological basis for his theology, psychology, and metaphysics.222 He realized that affirmations are, on the one hand, scientific insofar as they possess universality and necessity, and on the other, objective inasmuch as they are applicable to individual, contingent beings of immediate experience.223

Man encounters contingent particular things insofar as he is a sensory being. Truth is in the senses insofar as it "judges of things as they are,"224 that is, perceives its proper object, for example, the visual intuition of color. "Truth is not in senses, however, as something known by sense," for "it knows neither the nature of its act nor the proportion of this act to things."225 Falsity is said to be in the senses insofar as they occasion a misjudgment by the intellect, for example, in presenting the appearance of gold for what in reality is not genuine gold.226

Aquinas agreed with Aristotle that the human intellect is originally a clean slate (table Rosa) without any innate ideas. The mind must draw its materials from what is provided by the senses. How can a transition be effected from singular, contingent, sensible things to universal, necessary conclusions? Because no sensory object nor image can directly affect the spiritual soul, Thomas agreed with Aristotle that the rational soul must possess an "agent intellect" which "by a process of abstraction makes images received from the senses actually intelligible."227 He interpreted Augustine’s theory of illumination as "a proper intellectual light in man,"228 which abstracts "the universal from the particular, or the intelligible species from the phantasm."229 After reducing the universal from potential to actual intelligibility, the intellect presents to itself a possible likeness (species) of the thing. "The intellect actualized and informed by the species, as by a proper form, understands the thing itself" in an immanent act which "remains in the intelligence and bears a relation to the thing which it understands. . . ."230

On understanding the thing, the intellect "forms within itself a certain intention (concept) of the thing understood which is the meaning (ratio) of the thing, which the definition signifies."231 Because the intellect "understands the thing as separated from the material (individuating) conditions"232 and as universal, it needs to form a concept. Although the concept and the thing are different entities, they are intelligibly identical through the intentional "mode by which the similitude existing in the intellect is representative of the thing.233

Thus the conceptual likeness is not what is known but that by and in which the intellect understands the thing itself much as we do not perceive the mirror image but the object in itself which is reflected in the mirror. After grasping the thing via the concept, the intellect can then reflect on the concept as a construct of its own, as in logic.234 Were concepts that which is originally understood, scientific knowledge would be confined to concepts and what each mind judges of them -- however contradictory -- would be true.235 Truth, however, is the conformity of mind and reality.

The concept expresses the intellect’s apprehension of the essence of sensible things, not as individualized in them, but as "abstracted or set apart from matter and from material likenesses such as sense images"236 and hence from the individuality of the object. In its first intention, the intellect "directly" knows the nature. It then either relates this to all the instances of a nature, i.e., universalizes the nature, or through a "quasi-reflection" turns to the image presented by the imagination, thereby "indirectly" knowing the singular thing and discerning that the universal concept is applicable to this individual existent.237 Here Aquinas followed Aristotle in holding that the human intellect understands nothing without a phantasm or image, as is evident from introspection. Thus Aquinas’ theory of abstraction and conversion explains the synthesis of understanding universals and the perception of the concrete.

Favoring the Aristotelian position over the Augustinian view of the rational soul’s direct knowledge of itself, Aquinas reasoned that "the human intellect, which is actualized by a species of the thing understood, is itself understood through this same species. . . ."238 But how is this possible? In view of the Aristotelian principle that nothing is in the intellect which was not first in the senses, the problem arises whether the mind can go beyond sensible things to attain knowledge of the human soul and God, immaterial realities which can neither be objects of the senses nor representations of the imagination.

The human intellect as human, has as its proper object the essence of a material thing, whereas as intellect it is oriented towards the whole range of being: ". . . being is the primary and distinctive object of the intellect, just as sound is the primary object of hearing."239 Within the horizon of being in general, the human intellect indirectly knows immaterial realities insofar as they are manifested in and through concrete experience. For example, one "perceives himself to have an intellectual soul from the fact that he perceives himself to be intellectually acting" and understands "the nature of the human mind from the nature of the intellect’s activity."240 Likewise, the human intellect can know God insofar as sensible objects manifest his existence and can attain an analogical, indirect and imperfect knowledge of his nature.

Truth takes place originally in the judgment wherein the intellect, aware of itself as conforming to reality, "judges about the thing it has apprehended at the moment when it says that something is or is not," by composing and dividing in affirmative and negative propositions.241 Whereas the truth of speculative judgment lies in the intellect’s consciousness of its adequation to intelligible existence, the truth of practical judgment about acts to be done or things to be made resides in the intellect’s awareness of its correspondence with right desire, that is, the will inclining man to suitable goals by appropriate means.242

- First Principles. "All knowledge is in a certain sense implanted in us from the beginning . . . through the medium of universal conceptions . . . immediately known by the light of the agent intellect."243 With being as its horizon, the intellect immediately forms its judgment of things grasped in simple apprehension. When at the third level of knowledge, by judgement it clarifies explicitly the notion of being it affirms the first principles of intelligible being, for example, that being cannot be and not be under the same formal relationship. "These serve as universal principles through which we judge about other things, and in which we foreknow these others."244

Aquinas developed his moral theory on the basis of his theological, psychological, and epistemological conclusions. Within a teleological framework, he viewed every creature striving for its own development as sharing and growing in a resemblance to God: "Anything which tends towards its own perfection, tends towards the divine model."245 To show how man matures in the image of God, Aquinas analyzed man’s ethical life in its general structure and particular modalities.

Morality concerns human acts. Whereas actions of man such as eating and walking are simply physical or biological in themselves, they are said to be human insofar as they "proceed from the will of man according to the order of reason."246 Aquinas adopted Aristotle’s ethical teleology by viewing every human act as oriented towards an end which is the good apprehended by reason and intended by the will.247

Aquinas agreed with Aristotle that the ultimate end of human action is happiness. Because the will is orientated towards the universal good, man does not and cannot find complete fulfillment in any created good, such as riches, power, and bodily pleasure. Even Aristotle’s metaphysical contemplation of the ultimate cause is not fully satisfying since God as he is in himself remains hidden. The most that man can experience in this life is an imperfect happiness, because every created good offers only incomplete fulfillment and God — the uncreated sovereign good — is known imperfectly and analogically.248 The ultimate end which alone can fully realize man’s potentialities is God, "the universal good".249

The Thomistic man seems to be torn between two goals, one an imperfect happiness, and the other complete happiness which is unattainable in this life. Within the Christian perspective, Aquinas distinguished between the natural final end, contemplation of God, as the good proportionate to human powers and the supernatural ultimate end, vision of God, as the good transcending the power of human nature, namely eternal life with God.250 These ends, however, are not mutually exclusive. They refer to different dimensions of existence in the same concrete human being. In the attainment of imperfect felicity as his natural end, man does not put himself outside the way to his supernatural end. As we shall see later, the limitations of man’s natural end point beyond itself to a higher goal.

Aquinas analyzed the moral goodness of human acts within the horizon of man’s ultimate end. Since "the human will’s ultimate end is the supreme good, . . . God, "an act of the human will is good insofar as it is "ordered to the supreme good."251 Human acts are morally good insofar as they orientate man towards the ultimate good, and bad inasmuch as they defeat that purpose. Since man’s whole person is destined for happiness with God, the moral goodness of act refers to him in his total being, or man as man, and not simply under some aspect, for example, a good athlete. With knowledge of the purpose of an act, man can freely choose what leads to his ultimate end and perform good actions. Virtue enables man to be habitually disposed to good acts.

To determine how human actions can be inwardly directed towards God and consequently good, Aquinas analyzed their moral structure into object, circumstances, and end. First, "as the basic goodness of a natural thing is provided by its (specific) form, which makes it the kind of thing it is, so also the basic goodness of a moral act is provided by the befitting objective on which it is set, . . . for instance using what belongs to you."252 The appropriate objective agrees with "the reasonable order of life."253

Second, circumstances determine the morality of actions. As qualities like figure and complexion supervene on the specific nature given by the substantial form to man, so with moral activity "its full goodness as a whole . . . is filled out by the additions which are like its qualities: such are its due circumstances."254

Third, the motive or end shapes the structure of human action. As form actualizes matter, so the end (finis operantis: intention of the doer) intended by the will formally specifies the act which is orientated towards its objective (finis operis: purpose of deed).255 The end is good when it agrees with reason which directs the will to what can be referred to man’s intellectual form and hence, to what is reasonable and good.256 The will can desire either a seeming good, for evil attracts insofar as it appears as a value, or a genuine good, God or some created good which is referable to man’s final and all-embracing value. "Unless it gathers in all these values" — reasonable objective, due circumstances, and proper motive — "an action is not good simply speaking (without reservation), for as Dionusius says, each single defect causes evil, whereas complete integrity is required for good."257

Moral actions are regulated inwardly by virtue and outwardly by law. With Augustine, Aquinas defined virtue as "a good quality of mind by which one lives righteously. . . ."258 As a good habit, virtue disposes a rational being in a steady way to perform good actions, whereas vice is a settled disposition for bad activity. The subject of intellectual virtues, such as science, wisdom, and understanding, is reason, whereas the seat of moral virtues, such as justice, is the will which can impress the sensitive appetites with rational control and habituate the passions to the spiritual for man’s full development.259 The intellectual and moral virtues do not necessarily coexist in the same person, although, it is not possible to have the intellectual virtues without prudence. Gradually formed by repeated good acts, the virtuous disposition facilitates the performance of subsequent acts for the same end.

In reply, Aquinas pointed out that complete chastity, for example, can be virtuous when it conforms with reason enlightened by God who invites a person to that form of living. If such a way of life were done out of superstition or vainglory, it would be an excess. What determines whether a virtue, which appears as an extreme in one situation, is a mean in another circumstance, is its conformity to the rule of reason directing man’s acts to his final end.260

- Moral Virtues. Aquinas adapted Aristotle’s division of the cardinal moral virtues into prudence, justice, temperance, and fortitude, in view of his notion of God. For example, whereas Aristotle’s concept of the Divine involves no personal relationship between man and the divine, Aquinas’ notion of God as creator and governor of all things led to his regarding religion as a unique natural moral virtue, "annexed" to justice inasmuch as it renders to God due worship and reverence. However, it is superior to the other virtues because it "approaches more closely to God, and to justice because man is unequal to the duty of fully acquitting himself of his debt to God."261 Aquinas grounded Aristotelian virtue in man’s total dependence upon God as his beginning and end.

- Theological Virtues. Within the framework of religion, Aquinas surpassed Aristotle in the reality of "the theological virtues of faith, hope and charity [which] have God as the proper object of their acts," transcending the objects of the moral virtues as "means to the last end."262 In contrast to the natural acquisition of moral virtues, theological virtues are infused by God to lift human activity beyond its pursuits within the earthly city to fellowship with God. "Sympathy or connaturality for Divine things is the result of charity, which unites us to God."263 Natural moral virtues come to completion insofar as they are perfected by the supernatural virtue of charity which "is said to be the end of other virtues, because it directs all other virtues to its own end."264

- Hope. Likewise, Aristotle’s definition of hope as an emotional tendency for "a good that lies in the future and that is difficult, but possible to attain,"265 finds a deeper meaning in Thomas’ concept of hope as "a cleaving to God as source of absolute goodness, since hope is reliance on God’s help to bring us to blessedness."266 In hope, God shows himself not only as "the ultimate good sought after," but also as the source of confidence, "an unfailing source of help in attaining thereto, . . ."267

The outer principle of human activity is law which Thomas succinctly defined: "law is nought else than an ordinance of reason for the common good made by the authority who has care of the community, and promulgated."268 Law then is a function of practical reason which, as director of man’s activity towards his end, is the measure of human acts. Where reason is wanting, there is neither law nor equity, but sheer inequity. Virtue is conformity to the rule of reason. Reason, therefore, is the root of moral obligation. Since law aims essentially at the realization of good without reservation of any kind, it cannot restrict itself to the welfare of particular persons, but rather prescribes the good of the community. For that reason, the authority required for the legitimate establishing of law can belong only to someone duly invested with powers to lead his community, or to the community itself.

- Natural Law. Reason obliges according to the basic inclinations of human nature to constitute the natural law. Since the will naturally tends toward the good, practical reason dictates as "the first command of law, `that good is to be sought and done, evil to be avoided.’"269 This most general prescription expresses itself in three particular precepts for the good of human nature. The natural law commands every rational being to respect his three natural tendencies: first, to conserve his life and protect his health; second, to procreate and care for his wife and family; third, to develop his rational life by seeking truth and grow in social virtue.270

- Knowledge of Natural Law. Although the natural law is inherent in human nature, all people are not aware of its dictates. "As for its common principles," for example, to act intelligently, "here natural law is the same for all in requiring a right attitude towards it as well as recognition,"271 though reason can be confused about how they apply in particular cases. "As for particular specific points" — for instance, restoration of goods to an owner — "which are like conclusions drawn from common principles," Aquinas reasoned that "most people" are aware of them, though in "fewer cases"272 desire and "knowledge of what is right may be distorted by passion or bad custom."273 To overcome these unreasonable situations, he concluded to the value of divine positive law, for example, the ten commandments. In addition, considering the fact that not all men have the time or ability to discover the whole natural law, it was morally necessary that it should be positively expressed by God in the revelation of the Decalog to Moses.

- Eternal Law. The ultimate source of obligation must be found in the infinite Being who determines the nature of things and governs them274 in view of his eternal exemplar ideas. Influenced by Augustine, Thomas concluded that "the Eternal Law is nothing other than the exemplar of divine wisdom as directing the motions and acts of everything."275 Since man’s rational ordering of his natural tendencies is a created impression of the eternal law indelibly written on the tablets of the heart, so to speak, natural law is aptly called, "the sharing in the Eternal Law by intelligent creatures."276 The eternal law is applied by divine providence and executed by divine government. Because natural law is grounded in the eternal law of divine reason ordering man’s acts according to the unchangeable exemplar idea of human nature, it remains fundamentally the same.

- Human Law. "Human positive laws are either just or unjust. If they are just, they have binding force in the court of conscience from the Eternal Law from which they derive, . . ."277 The human legislator applies the natural law to particular cases in clearly defined enactments and supports it with effective sanctions.278 For example, murder, forbidden by natural law but in an unclear dictate without immediate sanctions, is clearly defined in positive enactments with sanctions added. When man-made law "is at variance with natural law, it will not be a law, but spoilt law,"279 and consequently does "not oblige in the court of conscience," unless perhaps a greater evil would follow from its nonobservance.280 But sooner or later it must be modified. Since the ruler receives his legislative power ultimately from God, he has no right to promulgate laws counter to the natural law.

- Law and Change. Law needs to adapt to a living situation in which reason develops insight into a better regulation, or changing conditions vary what is for the common benefit. However, stability and security dictate that law "should never be altered, unless the gain to the common well-being on one hand makes up for what has been lost on another."281 The natural law may change by addition or substraction. First, "many things over and above natural law have been added, by divine law as well as human laws, which are beneficial to social life."282 Second, "the first principles of natural law (e.g., do good and avoid evil) are altogether unalterable"283 by subtraction since they are founded on human nature which remains basically the same, whereas secondary precepts, "though not alterable in the majority of cases . . ., can nevertheless be changed on some particular and rare occasions,"284 for example, not returning goods to the owner who needs them to attack one’s country.

- Natural Institution. The State is founded on man’s nature as animal and social. First, "it is natural for man, more than any other animal to be a social and political animal, to live in a group."285 Whereas nature provides animals with clothing and means of defence, she leaves man to fare for himself by the use of reason in cooperation with other men, dividing their labor and specializing, for example, in medicine and agriculture. Second, man’s