22. Knowledge of the Existence of God
Part I
THE UNITY OF GOD
The mystery of God, known through revelation and accepted by faith, is the first problem discussed by dogmatic theology. God is “the first and the last” (Is 44:6), the beginning and end of everything.
Reason, enlightened by faith, faces this mystery and strives for a deeper understanding of what God is, his nature and operations, and how to describe his unity (God is one and there is only one God) and trinity of persons. The theological treatise in question has two parts:
The One God, which studies God’s being and his perfections
The Blessed Trinity, which deals with what is proper to each of the divine Persons, having studied what belongs to them in common.
The unity and trinity of God is the central mystery of the Christian faith. This explains the importance of this treatise: All other treatises, in one manner or another, will be founded on this one.
A deep and rigorous theology of God, One and Triune, is extremely important for Christian piety. Christian hope is grounded in knowing and loving God more and more in this life so as to enjoy his company forever in the next.
1. Natural Knowledge
Each person is, by nature and vocation, a religious being. We come from God and go continually to God; thus, we will not live a real human life if we do not choose freely to live this bond with God.
Every person has been created to live in communion with God; happiness is found in God. “When I abide by you with all my being, there will be no more sorrows or trials for me. My life—full of you—will be fully accomplished.”1
One can arrive at the knowledge of the existence of God in two ways: by the light of reason and by the grace of faith. Using reason (natural knowledge), listening to the message of the creatures, and listening to the prompting of conscience, a person can reach the certainty of God’s existence.2
The Catholic Church professes that “God, the origin and end of all things, can be known with certainty by the natural light of human reason, through the things that he created.”3 This is dogma, that is, a revealed truth solemnly defined by the Magisterium of the Church.
The Church had a double aim in defining this truth. First, she wanted to teach—once again and with her full authority—that the truth of the natural knowledge of the existence of God has always been part of her doctrinal heritage. It is clearly taught in Sacred Scripture (cf. Wis 13:1–9; Rom 1:19–21) as well as Tradition. She also wanted to condemn, with the same authority, the agnostic errors that were widespread during the second half of the nineteenth century.
Sacred Scripture describes the knowledge of God as mediate (obtained through created things), natural (reached through the light of the intelligence), universal (accessible to all people), certain (since creatures indubitably lead us to the Creator), and easy to attain (because it requires only the natural use of reason). The definition of the First Vatican Council quoted above underscores these characteristics.
2. The Existence of God Can Be Proved by Reason
Can we demonstrate God’s existence? The First Vatican Council specified only that one can know God naturally. Nevertheless, the possibility of proving God’s existence is included implicitly in the dogmatic definition. This was the mind of the Council, as later teachings of the Magisterium show. Among the documents relevant to this topic, the motu proprio Sacrorum Antistitum (issued by St. Pius X in 1910) is especially significant. It states: “God, the origin and end of all things, can be known and demonstrated with certainty by the natural light of reason starting from the created world, that is, from the visible works of creation, as a cause is known through its effects.”4
These words speak of the starting point of the proof (the visible works of creation) and its basis (as a cause from its effects), namely, the principle of causality, which is the experience of causality analyzed philosophically.
3. Proof of the Existence of God
The Church affirms that the existence of God can be demonstrated rationally. The best proof of this assertion is the existence of such demonstrations. Philosophers and theologians have developed multiple demonstrations throughout the centuries. All have great relevance and speculative interest to the current discussion. Those of St. Thomas Aquinas are among the most popular. They are known as the Five Ways. He used arguments from earlier authors (mainly Aristotle, but also Plato, St. Augustine, St. John Damascene, and Avicenna) in his demonstrations. Nevertheless, he was not merely a compiler; he was able to leave the imprint of his own genius and peculiar style in the proofs. Before studying the Five Ways, we must mention other arguments that are worthy of study as well. These include St. Augustine’s argument and the ontological proof of St. Anselm (whose demonstrative force is contestable). The ontological proof was later recast by other authors, such as Descartes and Leibniz.
The Ways of St. Thomas5 are five metaphysical arguments based on the rational development of sensory data. The development uses very specific concepts in Aristotelian-Thomistic philosophy, such as the notions of esse (or actus essendi), causality, and participation. To understand the Ways of St. Thomas properly, it is necessary to be familiar with these notions. This is a requirement to understand the proofs according to the spirit of their author, as scientific rigor demands. Only in this way can the solidity and eternal value of the proofs truly be appreciated.
The first key to the understanding given by the Ways is the multiplicity of beings we find in the world. The existence and variety of creatures bear witness to a real distinction between their essence (what they are) and their esse or act of being (that by which they are). This fact, in turn, requires the existence of a Supreme Being whose very essence is to be, thus possessing the power to communicate esse—the act of being—to other things. We know from experience that no existing being has, in itself, its own reason for being, since nothing can give the act of being to itself. No finite being is capable of accounting for the act by which it is. This lack on the part of finite beings means that a “First Cause” of the act of being of each thing must exist. The composition of essence and esse, proper of limited beings, is not found in this “Cause.” The essence of this “Cause” should precisely be his esse.
The second metaphysical key to the Ways is the notion of causality. In Aristotelian-Thomistic philosophy, causality is not merely an external action that transforms a passive object. Rather, it is a relation by which an agent actualizes a pre-existent potential in a passive object. Causality is the union of active intervention and a passive disposition. Because it is a union, causality requires a cause of the agent’s causality in the agent, that is, a cause of its being. With this in mind, it is possible to understand why the principle of causality (“every effect has a cause”) leads to God, since secondary causes cannot account for their own causality. There must be a First Cause, the cause of causality. That cause is God.
The notion of participation is the basis for the Fourth Way. It is closely connected to the two previous notions. It can be defined as simply the partial possession of an act or perfection possessed fully by another. If we apply this notion to the act of being, we conclude that all things possess the act of being in a partial, participated way. Therefore, a “Being by essence” in which all other beings participate must exist. This Being possesses the full perfection of Being as his own and is, therefore, the cause of the partial possession of Being in others. This Being by essence is God.
The five ways are similar in structure, and their elements may be summarized as follows:
· Starting point: a fact of experience, metaphysically considered
· Application of the principle of causality to this starting point
· Recourse to infinity in a series of subordinate causes is discarded (in the first three ways)
· Conclusion: God exists
We will now develop the First and Fifth Ways and outline the other three.
3a) The First Way
Starting point: We start from the experience of motion. “It is certain,” writes St Thomas, “and evident to our senses, that in the world some things are in motion.”
Motion, in this context, is the passage from potential to act. Potential is what could be something but is not that something yet. Act is what already is. All finite beings are composed of potential and act.
Application of the principle of causality: “Now whatever is in motion is put in motion by another, for nothing can be in motion unless it is in potentiality to that towards which it is in motion; whereas a thing moves inasmuch as it is in act.… Now it is not possible that the same thing should be at once in actuality and potentiality in the same respect, but only in different respects.… It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, i.e., that it should move itself. Therefore, whatever is in motion must be put in motion by another.”
Once motion is defined as the passage from potential to act, applying the principle of causality is simple: Whatever moves is moved by another. As St. Thomas shows in the above quotation, if we claimed that something moved itself, we would go against the principle of non-contradiction (a thing cannot be itself and another at the same time in the same sense), which is a first principle of our knowledge and understanding of reality.
Impossibility of proceeding ad infinitum: “If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover; seeing that subsequent movers move only inasmuch as they are put in motion by the first mover.”
At this point, the reasoning proceeds as follows: Every effect (what is moved) has its proper cause. This cause also moves, and, therefore, is moved, and, therefore, has in turn its own cause and so on for the third, fourth, and succeeding causes. These causes are essentially subordinated in the present; they all have to act in the present for the effect to take place. For example, for a stone to move, it has to be pushed by a staff, which in turn is held by a hand, and so on. They all have to act at the same time.
This type of subordinate cause is different from those accidentally subordinated in the past. Causes of the latter type do not have to act all at the same time in order to produce the effect. For example, for a man to exist, it is not necessary for his father, grandfather, and great-grandfather to exist all at the same time.
It is not possible to proceed to infinity in the first way because it would require eventually denying the very existence of motion. Subordinate movers cause movement only insofar as they themselves are moved. This demands the existence of a first mover who is not moved by any other, that is, an unmoved mover.
Conclusion: “Therefore, it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God.” This unmoved mover is God because he moves without himself being moved, that is, he acts without passing from potency to act, so he is always in act. He is his own activity and his own Being. This subsistent esse, this pure act of Being, is God.
3b) The Fifth Way
Starting point: We start from the experience of purpose in the world—everything moves toward an end. “We see that things that lack intelligence (such as natural bodies) act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that they achieve their end not fortuitously, but designedly.”
Beings endowed with intelligence are capable of knowing what is good for them and moving toward it. They know both the end and the means, and they act intentionally, for a purpose. However, those lacking adequate knowledge cannot direct themselves to their end. Nevertheless, they also act for an end. This demands a cause that can explain such behavior.
Application of causality: “Now whatever lacks intelligence cannot move toward an end, unless it be directed by some being endowed with knowledge and intelligence, as the arrow is shot to its mark by the archer.”
The evidence of purpose and governance in the world implies the existence of an intelligent being who knows the end and the means to reach it. This explains why irrational beings always act in the most appropriate way to reach what is good for them.
Conclusion: “Therefore, some intelligent being exists by whom all natural things are ordered to their end, and this being we call God.” This supreme intelligence, whose being is his intelligence, is God—the pure act of Being.
3c) Outline of the Other Ways
The Second Way starts from efficient causality and reaches God as the Uncaused Cause.
The Third Way begins with the experience of generation and corruption and shows that God is the only being necessary in itself.
The Fourth Way starts by observing that some creatures are more perfect than others and concludes that God is the source of all perfection.
We should consider now whether the Five Ways are absolutely conclusive, that is, whether or not they can prove the existence of God to everybody. In fact, some people dismiss them as inconclusive. The arguments, however, are solidly grounded and logically irrefutable. Sometimes, the rejection is due to ignorance of the philosophy on which they are based. Another factor that sometimes leads to their rejection is the prevalent role of human freedom in our knowledge of God. As they prove the existence of God, the Five Ways of St. Thomas call for a personal commitment to this truth. This involves certain concrete obligations toward the Creator at a personal level. If a person is not willing to accept dependence on God, he will voluntarily reject any argument proving his existence.
4. The Existence of God is Also an Object of Faith
God has revealed his existence. Thus, this truth is also an object of faith. God is One; this second truth—rooted in the Old Testament—is inseparable from the fact of his existence.
Sacred Scripture reveals the personal nature of God, his infinite power in creation, oneness, infinite perfections, and Trinity of Persons. God revealed himself to Israel as the One. “Hear, O Israel: The Lord our God is one Lord; and you shall love the Lord your God with all your heart, and with all your soul, and with all your might” (Dt 6:4–5). Through the prophets, God invited Israel and all nations to turn to him. “Turn to me and be saved, all you ends of the earth! For I am God, and there is no other.… To me every knee shall bow, and every tongue shall swear. Only in the Lord, it shall be said of me, are righteousness and strength” (Is 45:22–24; cf. Phil 2:10–11).
Jesus confirmed that God, the Lord, is One, and that he should be loved with all one’s heart, with all one’s soul, with all one’s mind, and with all one’s strength (cf. Mk 12:29–30).
The acceptance of revelation through the gift and commitment of faith is a source of knowledge about God’s existence. The sacred books do not offer any formal demonstration of his existence, although several proofs are implicit. They are not needed since God is the main protagonist of the Bible. His active presence is constant and evident from the very first verse to the last. Scripture itself calls the person who does not recognize God in all his works a “fool” (cf. Wis 14).
4a) God’s Name
God revealed his name to his people, Israel. A person’s name expresses his essence, identity, and sense of his life. God has a name. He is not merely “an anonymous force.”
God revealed himself gradually and with diverse names, but the fundamental revelation of his name was to Moses through the burning bush on Sinai: “I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob” (Ex 3:6). God is the God of the ancestors, the One who called and guided the patriarchs in their wanderings. He is faithful and compassionate; he remembers his people and promises; he comes to liberate his people from slavery. Since God is almighty and loves his people beyond space and time, he will use all his might for this purpose.
4b) “I Am Who I Am”
Then Moses said to God, “If I come to the people of Israel and say to them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’ what shall I say to them?” God said to Moses, “I am who I am.” And he said, “Say this to the people of Israel, ‘I am has sent me to you.’” God also said to Moses, “Say this to the people of Israel, ‘The Lord, the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has sent me to you’: this is my name for ever, and thus I am to be remembered throughout all generations.” (Ex 3:13–15)
God revealed his mysterious name “I am who I am” or yhwh. It reveals God as he is, much above anything we may say or understand. He is “a God who hidest thyself” (Is 45:15); God’s name is “wonderful” (Jgs 13:18); still, he is a God who becomes intimate with people.
In revealing his name, God also reveals his fidelity. As he was faithful in the past (“I am the God of your father”), he will be faithful in the future (“I will be with you” [Ex 3:12]) for the sake of his people.
Out of respect for God’s sanctity, the people of Israel do not utter the name of God. While reading Sacred Scripture they say God’s title “Lord” (Adonai in Hebrew, or Kyrios in Greek) instead. Jesus was acclaimed with the same title, which revealed his divinity: “Jesus is Lord.”
5. Principal Errors Regarding the Existence and Natural Knowledge of God
5a) Atheism and its Moral Responsibility
The Second Vatican Council clearly states in the pastoral constitution Gaudium et Spes that atheism is not something spontaneous in man.6 It is, rather, an unnatural development that has both intellectual and moral causes. Knowing and loving God is the first commandment of the Law of God, positively prescribed by the natural law written in the hearts of mankind. Its fulfillment is necessary for salvation. The unnatural passage into atheism presupposes the mystery of sin, which turns the hierarchy of values of the person upside-down. The First Vatican Council mentions a negligent training in the faith, sidestepping important matters, and defective explanation of the doctrine—rendering it either trivial or unintelligible, unable to inspire one’s life—as some causes of atheism.
As for the intellectual roots of modern atheism, foremost among them is the theory of immanence. Essentially, immanentism reduces the reality of things to their being known by a subject. Thus, being is reduced to a mere mental structure. The theory of immanence could be summarized as “Without thought, there is no being,” or “To be is to think.”
Atheism appears with several façades. One frequent form is practical materialism, which limits human needs and ambitions to space and time. Another form is atheistic humanism, which falsely considers man as the end of himself, the sole maker and creator of his own history (propriae suae historiae solus artifex et demiurgus).7 Finally, the common current form of atheism expects man’s salvation by a kind of earthly economic and social liberation for which “religion, of its very nature, thwarts such emancipation by raising man’s hopes in a future life, thus both deceiving him and discouraging him from working for a better form of life on earth.”8
5b) Agnosticism
Agnosticism is a philosophical tenet that denies the ability of human reason to transcend the limits of sensorial experience. This leads to erroneous consequences regarding the natural knowledge of God; if it were true, human reason would not be able to attain knowledge of God and prove his existence. Consequently, agnostics propose the suspension of judgment regarding God and the last end of man. The most representative agnostic school is Kantianism, which was singled out and condemned by the First Vatican Council in the dogmatic definition Dei Filius. This error greatly influenced modernism, which was in turn condemned by St. Pius X in his encyclical Pascendi.9
The agnostic refuses to deny God, allowing for the existence of a transcendent being who cannot reveal himself and about whom no one can say anything. Agnosticism frequently results in indifference and escapism from moral responsibility.
5c) Fideism and Traditionalism
Fideism and traditionalism have agnostic traits. They both deny the ability of human reason to reach transcendent truths. One holds instead that faith alone can give certainty (i.e., fideism of Bautain). For the other, the only source of certainty is the tradition of a primitive revelation, kept and transmitted from generation to generation (i.e., traditionalism of Bonnetty).
In either context, “transcendent truths” are not just the strictly supernatural truths, which human reason cannot know by its own power. They also include the fundamental truths of the metaphysical, moral, and religious order. It is regarding the latter that both schools disqualify human reason. Hence, they were condemned by the Church in documents of Gregory XVI and Pius IX.10
5d) Ontologism
Ontologism postulates that human reason immediately perceives the Absolute Being. God himself would be the proper object of the mind; that is, the intellect would immediately know the infinite Being and, through him, all the other things. Hence, this erroneous theory holds that the immediate knowledge of God is essential to the intellect and without it no other knowledge is possible. It contradicts both sound philosophical reason and the Christian doctrine on the power of our created mind. Ontologism leads to serious errors in other fields as well. This error was condemned by the Church in a decree of the Holy Office in 1861.11 The doctrines of its most representative proponent, Rosmini, were condemned by the decree Post Obitum in 1887.12
6. Our Knowledge of God Is Analogical
As we have seen, God can be known by created intellects, but he is also incomprehensible because his being and the mysteries of his intimate life infinitely surpass the capacity of human reason. Man cannot fully comprehend God, but he can acquire a certain knowledge of the essence of God, even in the present life. This knowledge is mediate and analogical.13
6a) The Analogy of Being
Our analogical knowledge is based on the analogy of being. The analogy of being is the likeness or similarity between all beings by participation and the Being by essence. As a result of the total causality of God, all creatures bear a certain likeness to him. All agents bring out effects similar to themselves (as the philosophical adage puts it) and, consequently, all effects bear some resemblance to their causes. Accordingly, all creatures have a certain degree of similarity with the Creator, and this similarity varies according to the degree of perfection of their being.
6b) Univocity and Equivocity
Analogy is intermediate between univocity and equivocity. In a comparison, analogy entails both similarity (univocity) and dissimilarity (equivocity). In the case of the analogy of creatures with God, the similarity is minimal (although real, i.e., based on causality) and the dissimilarity is infinite. The human mind can discover something about God through the similarity between creatures and him. It is very little, but it is something really found in God; otherwise, it would not be found in the creatures, which were made by God out of nothing. We can, therefore, speak about God on the basis of the perfections found in creatures.
The perfections found in creatures cannot be attributed univocally to God because these same perfections are found in God in an infinitely superior way. Still, it is not an equivocal predication either, because these perfections are not totally different in God and in creatures—they maintain some resemblance. Therefore, the predication must be analogical—halfway between univocity and equivocity.
6c) Affirmation, Negation, and Eminence
Our analogical knowledge of God includes the ways of affirmation, negation, and eminence.
The way of affirmation is the first step in our analogical knowledge of God. It implies attributing all the pure perfections that are found in creatures (such as truth, goodness, beauty, life, and intelligence) to God. The concept of pure perfection excludes any imperfection whatsoever.
The second step is the way of negation, by which we deny that these pure perfections are found in God in the same way as they are found in creatures, whose perfections are always limited.
Consequently, it is necessary to proceed to the way of eminence: We admit that these same perfections are in God but in an ineffable and eminent way, being infinite and identified with the divine essence. These ways are not three different ways to God through creatures, but rather three consecutive stages in a rational path to God.
The pure perfections of the creatures are predicated of God in a proper sense because they are really present in him at an infinitely greater scale. The mixed perfections, however, are necessarily mingled with imperfections because they are exclusive of creatures, and can be attributed to God only in an improper or metaphorical sense.
6d) Analogical Knowledge Is True but Imperfect Knowledge
Knowledge is true when it agrees with the reality of the known object. In other words, there is true knowledge when the idea produced by the mind in the act of knowing is an accurate representation of the known object. In the case of our analogical knowledge of God, the divine perfections are the known object. This knowledge is based on the real and true likeness between the creatures’ perfections and God’s. In this case, human reason really reaches God through analogy. However, given the infinite distance between God and creatures and the infinite dissimilarity implied in the analogy between them, this type of knowledge is necessarily imperfect. We know God truly, but his essence is infinitely richer than whatever degree of knowledge we may acquire about it.
Footnotes:
1. St. Augustine, Confessions, 10.28.39.
2. Cf. CCC, 27–30, 44–46.
3. DS 3004, 3026; cf. CCC, 36–38.
4. Cf. DS 3538; CCC, 31–35.
5. Cf. ST, I, q. 2, a. 3; cf. St. Thomas Aquinas, Summa Contra Gentiles, 1.13.
6. Cf. GS, 19–21; cf. CCC, 2123–2126.
7. Cf. GS, 20.
8. Ibid.
9. Cf. DS 3475–3500; CCC, 2127–2128.
10. Cf. DS 2751–2756 for Bautain, DS 2811–2814 for Bonnetty.
11. Cf. DS 2841ff.
12. Cf. DS 3201ff.
13. Cf. CCC, 39–43.
THE UNITY OF GOD
The mystery of God, known through revelation and accepted by faith, is the first problem discussed by dogmatic theology. God is “the first and the last” (Is 44:6), the beginning and end of everything.
Reason, enlightened by faith, faces this mystery and strives for a deeper understanding of what God is, his nature and operations, and how to describe his unity (God is one and there is only one God) and trinity of persons. The theological treatise in question has two parts:
The One God, which studies God’s being and his perfections
The Blessed Trinity, which deals with what is proper to each of the divine Persons, having studied what belongs to them in common.
The unity and trinity of God is the central mystery of the Christian faith. This explains the importance of this treatise: All other treatises, in one manner or another, will be founded on this one.
A deep and rigorous theology of God, One and Triune, is extremely important for Christian piety. Christian hope is grounded in knowing and loving God more and more in this life so as to enjoy his company forever in the next.
1. Natural Knowledge
Each person is, by nature and vocation, a religious being. We come from God and go continually to God; thus, we will not live a real human life if we do not choose freely to live this bond with God.
Every person has been created to live in communion with God; happiness is found in God. “When I abide by you with all my being, there will be no more sorrows or trials for me. My life—full of you—will be fully accomplished.”1
One can arrive at the knowledge of the existence of God in two ways: by the light of reason and by the grace of faith. Using reason (natural knowledge), listening to the message of the creatures, and listening to the prompting of conscience, a person can reach the certainty of God’s existence.2
The Catholic Church professes that “God, the origin and end of all things, can be known with certainty by the natural light of human reason, through the things that he created.”3 This is dogma, that is, a revealed truth solemnly defined by the Magisterium of the Church.
The Church had a double aim in defining this truth. First, she wanted to teach—once again and with her full authority—that the truth of the natural knowledge of the existence of God has always been part of her doctrinal heritage. It is clearly taught in Sacred Scripture (cf. Wis 13:1–9; Rom 1:19–21) as well as Tradition. She also wanted to condemn, with the same authority, the agnostic errors that were widespread during the second half of the nineteenth century.
Sacred Scripture describes the knowledge of God as mediate (obtained through created things), natural (reached through the light of the intelligence), universal (accessible to all people), certain (since creatures indubitably lead us to the Creator), and easy to attain (because it requires only the natural use of reason). The definition of the First Vatican Council quoted above underscores these characteristics.
2. The Existence of God Can Be Proved by Reason
Can we demonstrate God’s existence? The First Vatican Council specified only that one can know God naturally. Nevertheless, the possibility of proving God’s existence is included implicitly in the dogmatic definition. This was the mind of the Council, as later teachings of the Magisterium show. Among the documents relevant to this topic, the motu proprio Sacrorum Antistitum (issued by St. Pius X in 1910) is especially significant. It states: “God, the origin and end of all things, can be known and demonstrated with certainty by the natural light of reason starting from the created world, that is, from the visible works of creation, as a cause is known through its effects.”4
These words speak of the starting point of the proof (the visible works of creation) and its basis (as a cause from its effects), namely, the principle of causality, which is the experience of causality analyzed philosophically.
3. Proof of the Existence of God
The Church affirms that the existence of God can be demonstrated rationally. The best proof of this assertion is the existence of such demonstrations. Philosophers and theologians have developed multiple demonstrations throughout the centuries. All have great relevance and speculative interest to the current discussion. Those of St. Thomas Aquinas are among the most popular. They are known as the Five Ways. He used arguments from earlier authors (mainly Aristotle, but also Plato, St. Augustine, St. John Damascene, and Avicenna) in his demonstrations. Nevertheless, he was not merely a compiler; he was able to leave the imprint of his own genius and peculiar style in the proofs. Before studying the Five Ways, we must mention other arguments that are worthy of study as well. These include St. Augustine’s argument and the ontological proof of St. Anselm (whose demonstrative force is contestable). The ontological proof was later recast by other authors, such as Descartes and Leibniz.
The Ways of St. Thomas5 are five metaphysical arguments based on the rational development of sensory data. The development uses very specific concepts in Aristotelian-Thomistic philosophy, such as the notions of esse (or actus essendi), causality, and participation. To understand the Ways of St. Thomas properly, it is necessary to be familiar with these notions. This is a requirement to understand the proofs according to the spirit of their author, as scientific rigor demands. Only in this way can the solidity and eternal value of the proofs truly be appreciated.
The first key to the understanding given by the Ways is the multiplicity of beings we find in the world. The existence and variety of creatures bear witness to a real distinction between their essence (what they are) and their esse or act of being (that by which they are). This fact, in turn, requires the existence of a Supreme Being whose very essence is to be, thus possessing the power to communicate esse—the act of being—to other things. We know from experience that no existing being has, in itself, its own reason for being, since nothing can give the act of being to itself. No finite being is capable of accounting for the act by which it is. This lack on the part of finite beings means that a “First Cause” of the act of being of each thing must exist. The composition of essence and esse, proper of limited beings, is not found in this “Cause.” The essence of this “Cause” should precisely be his esse.
The second metaphysical key to the Ways is the notion of causality. In Aristotelian-Thomistic philosophy, causality is not merely an external action that transforms a passive object. Rather, it is a relation by which an agent actualizes a pre-existent potential in a passive object. Causality is the union of active intervention and a passive disposition. Because it is a union, causality requires a cause of the agent’s causality in the agent, that is, a cause of its being. With this in mind, it is possible to understand why the principle of causality (“every effect has a cause”) leads to God, since secondary causes cannot account for their own causality. There must be a First Cause, the cause of causality. That cause is God.
The notion of participation is the basis for the Fourth Way. It is closely connected to the two previous notions. It can be defined as simply the partial possession of an act or perfection possessed fully by another. If we apply this notion to the act of being, we conclude that all things possess the act of being in a partial, participated way. Therefore, a “Being by essence” in which all other beings participate must exist. This Being possesses the full perfection of Being as his own and is, therefore, the cause of the partial possession of Being in others. This Being by essence is God.
The five ways are similar in structure, and their elements may be summarized as follows:
· Starting point: a fact of experience, metaphysically considered
· Application of the principle of causality to this starting point
· Recourse to infinity in a series of subordinate causes is discarded (in the first three ways)
· Conclusion: God exists
We will now develop the First and Fifth Ways and outline the other three.
3a) The First Way
Starting point: We start from the experience of motion. “It is certain,” writes St Thomas, “and evident to our senses, that in the world some things are in motion.”
Motion, in this context, is the passage from potential to act. Potential is what could be something but is not that something yet. Act is what already is. All finite beings are composed of potential and act.
Application of the principle of causality: “Now whatever is in motion is put in motion by another, for nothing can be in motion unless it is in potentiality to that towards which it is in motion; whereas a thing moves inasmuch as it is in act.… Now it is not possible that the same thing should be at once in actuality and potentiality in the same respect, but only in different respects.… It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, i.e., that it should move itself. Therefore, whatever is in motion must be put in motion by another.”
Once motion is defined as the passage from potential to act, applying the principle of causality is simple: Whatever moves is moved by another. As St. Thomas shows in the above quotation, if we claimed that something moved itself, we would go against the principle of non-contradiction (a thing cannot be itself and another at the same time in the same sense), which is a first principle of our knowledge and understanding of reality.
Impossibility of proceeding ad infinitum: “If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover; seeing that subsequent movers move only inasmuch as they are put in motion by the first mover.”
At this point, the reasoning proceeds as follows: Every effect (what is moved) has its proper cause. This cause also moves, and, therefore, is moved, and, therefore, has in turn its own cause and so on for the third, fourth, and succeeding causes. These causes are essentially subordinated in the present; they all have to act in the present for the effect to take place. For example, for a stone to move, it has to be pushed by a staff, which in turn is held by a hand, and so on. They all have to act at the same time.
This type of subordinate cause is different from those accidentally subordinated in the past. Causes of the latter type do not have to act all at the same time in order to produce the effect. For example, for a man to exist, it is not necessary for his father, grandfather, and great-grandfather to exist all at the same time.
It is not possible to proceed to infinity in the first way because it would require eventually denying the very existence of motion. Subordinate movers cause movement only insofar as they themselves are moved. This demands the existence of a first mover who is not moved by any other, that is, an unmoved mover.
Conclusion: “Therefore, it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God.” This unmoved mover is God because he moves without himself being moved, that is, he acts without passing from potency to act, so he is always in act. He is his own activity and his own Being. This subsistent esse, this pure act of Being, is God.
3b) The Fifth Way
Starting point: We start from the experience of purpose in the world—everything moves toward an end. “We see that things that lack intelligence (such as natural bodies) act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that they achieve their end not fortuitously, but designedly.”
Beings endowed with intelligence are capable of knowing what is good for them and moving toward it. They know both the end and the means, and they act intentionally, for a purpose. However, those lacking adequate knowledge cannot direct themselves to their end. Nevertheless, they also act for an end. This demands a cause that can explain such behavior.
Application of causality: “Now whatever lacks intelligence cannot move toward an end, unless it be directed by some being endowed with knowledge and intelligence, as the arrow is shot to its mark by the archer.”
The evidence of purpose and governance in the world implies the existence of an intelligent being who knows the end and the means to reach it. This explains why irrational beings always act in the most appropriate way to reach what is good for them.
Conclusion: “Therefore, some intelligent being exists by whom all natural things are ordered to their end, and this being we call God.” This supreme intelligence, whose being is his intelligence, is God—the pure act of Being.
3c) Outline of the Other Ways
The Second Way starts from efficient causality and reaches God as the Uncaused Cause.
The Third Way begins with the experience of generation and corruption and shows that God is the only being necessary in itself.
The Fourth Way starts by observing that some creatures are more perfect than others and concludes that God is the source of all perfection.
We should consider now whether the Five Ways are absolutely conclusive, that is, whether or not they can prove the existence of God to everybody. In fact, some people dismiss them as inconclusive. The arguments, however, are solidly grounded and logically irrefutable. Sometimes, the rejection is due to ignorance of the philosophy on which they are based. Another factor that sometimes leads to their rejection is the prevalent role of human freedom in our knowledge of God. As they prove the existence of God, the Five Ways of St. Thomas call for a personal commitment to this truth. This involves certain concrete obligations toward the Creator at a personal level. If a person is not willing to accept dependence on God, he will voluntarily reject any argument proving his existence.
4. The Existence of God is Also an Object of Faith
God has revealed his existence. Thus, this truth is also an object of faith. God is One; this second truth—rooted in the Old Testament—is inseparable from the fact of his existence.
Sacred Scripture reveals the personal nature of God, his infinite power in creation, oneness, infinite perfections, and Trinity of Persons. God revealed himself to Israel as the One. “Hear, O Israel: The Lord our God is one Lord; and you shall love the Lord your God with all your heart, and with all your soul, and with all your might” (Dt 6:4–5). Through the prophets, God invited Israel and all nations to turn to him. “Turn to me and be saved, all you ends of the earth! For I am God, and there is no other.… To me every knee shall bow, and every tongue shall swear. Only in the Lord, it shall be said of me, are righteousness and strength” (Is 45:22–24; cf. Phil 2:10–11).
Jesus confirmed that God, the Lord, is One, and that he should be loved with all one’s heart, with all one’s soul, with all one’s mind, and with all one’s strength (cf. Mk 12:29–30).
The acceptance of revelation through the gift and commitment of faith is a source of knowledge about God’s existence. The sacred books do not offer any formal demonstration of his existence, although several proofs are implicit. They are not needed since God is the main protagonist of the Bible. His active presence is constant and evident from the very first verse to the last. Scripture itself calls the person who does not recognize God in all his works a “fool” (cf. Wis 14).
4a) God’s Name
God revealed his name to his people, Israel. A person’s name expresses his essence, identity, and sense of his life. God has a name. He is not merely “an anonymous force.”
God revealed himself gradually and with diverse names, but the fundamental revelation of his name was to Moses through the burning bush on Sinai: “I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob” (Ex 3:6). God is the God of the ancestors, the One who called and guided the patriarchs in their wanderings. He is faithful and compassionate; he remembers his people and promises; he comes to liberate his people from slavery. Since God is almighty and loves his people beyond space and time, he will use all his might for this purpose.
4b) “I Am Who I Am”
Then Moses said to God, “If I come to the people of Israel and say to them, ‘The God of your fathers has sent me to you,’ and they ask me, ‘What is his name?’ what shall I say to them?” God said to Moses, “I am who I am.” And he said, “Say this to the people of Israel, ‘I am has sent me to you.’” God also said to Moses, “Say this to the people of Israel, ‘The Lord, the God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has sent me to you’: this is my name for ever, and thus I am to be remembered throughout all generations.” (Ex 3:13–15)
God revealed his mysterious name “I am who I am” or yhwh. It reveals God as he is, much above anything we may say or understand. He is “a God who hidest thyself” (Is 45:15); God’s name is “wonderful” (Jgs 13:18); still, he is a God who becomes intimate with people.
In revealing his name, God also reveals his fidelity. As he was faithful in the past (“I am the God of your father”), he will be faithful in the future (“I will be with you” [Ex 3:12]) for the sake of his people.
Out of respect for God’s sanctity, the people of Israel do not utter the name of God. While reading Sacred Scripture they say God’s title “Lord” (Adonai in Hebrew, or Kyrios in Greek) instead. Jesus was acclaimed with the same title, which revealed his divinity: “Jesus is Lord.”
5. Principal Errors Regarding the Existence and Natural Knowledge of God
5a) Atheism and its Moral Responsibility
The Second Vatican Council clearly states in the pastoral constitution Gaudium et Spes that atheism is not something spontaneous in man.6 It is, rather, an unnatural development that has both intellectual and moral causes. Knowing and loving God is the first commandment of the Law of God, positively prescribed by the natural law written in the hearts of mankind. Its fulfillment is necessary for salvation. The unnatural passage into atheism presupposes the mystery of sin, which turns the hierarchy of values of the person upside-down. The First Vatican Council mentions a negligent training in the faith, sidestepping important matters, and defective explanation of the doctrine—rendering it either trivial or unintelligible, unable to inspire one’s life—as some causes of atheism.
As for the intellectual roots of modern atheism, foremost among them is the theory of immanence. Essentially, immanentism reduces the reality of things to their being known by a subject. Thus, being is reduced to a mere mental structure. The theory of immanence could be summarized as “Without thought, there is no being,” or “To be is to think.”
Atheism appears with several façades. One frequent form is practical materialism, which limits human needs and ambitions to space and time. Another form is atheistic humanism, which falsely considers man as the end of himself, the sole maker and creator of his own history (propriae suae historiae solus artifex et demiurgus).7 Finally, the common current form of atheism expects man’s salvation by a kind of earthly economic and social liberation for which “religion, of its very nature, thwarts such emancipation by raising man’s hopes in a future life, thus both deceiving him and discouraging him from working for a better form of life on earth.”8
5b) Agnosticism
Agnosticism is a philosophical tenet that denies the ability of human reason to transcend the limits of sensorial experience. This leads to erroneous consequences regarding the natural knowledge of God; if it were true, human reason would not be able to attain knowledge of God and prove his existence. Consequently, agnostics propose the suspension of judgment regarding God and the last end of man. The most representative agnostic school is Kantianism, which was singled out and condemned by the First Vatican Council in the dogmatic definition Dei Filius. This error greatly influenced modernism, which was in turn condemned by St. Pius X in his encyclical Pascendi.9
The agnostic refuses to deny God, allowing for the existence of a transcendent being who cannot reveal himself and about whom no one can say anything. Agnosticism frequently results in indifference and escapism from moral responsibility.
5c) Fideism and Traditionalism
Fideism and traditionalism have agnostic traits. They both deny the ability of human reason to reach transcendent truths. One holds instead that faith alone can give certainty (i.e., fideism of Bautain). For the other, the only source of certainty is the tradition of a primitive revelation, kept and transmitted from generation to generation (i.e., traditionalism of Bonnetty).
In either context, “transcendent truths” are not just the strictly supernatural truths, which human reason cannot know by its own power. They also include the fundamental truths of the metaphysical, moral, and religious order. It is regarding the latter that both schools disqualify human reason. Hence, they were condemned by the Church in documents of Gregory XVI and Pius IX.10
5d) Ontologism
Ontologism postulates that human reason immediately perceives the Absolute Being. God himself would be the proper object of the mind; that is, the intellect would immediately know the infinite Being and, through him, all the other things. Hence, this erroneous theory holds that the immediate knowledge of God is essential to the intellect and without it no other knowledge is possible. It contradicts both sound philosophical reason and the Christian doctrine on the power of our created mind. Ontologism leads to serious errors in other fields as well. This error was condemned by the Church in a decree of the Holy Office in 1861.11 The doctrines of its most representative proponent, Rosmini, were condemned by the decree Post Obitum in 1887.12
6. Our Knowledge of God Is Analogical
As we have seen, God can be known by created intellects, but he is also incomprehensible because his being and the mysteries of his intimate life infinitely surpass the capacity of human reason. Man cannot fully comprehend God, but he can acquire a certain knowledge of the essence of God, even in the present life. This knowledge is mediate and analogical.13
6a) The Analogy of Being
Our analogical knowledge is based on the analogy of being. The analogy of being is the likeness or similarity between all beings by participation and the Being by essence. As a result of the total causality of God, all creatures bear a certain likeness to him. All agents bring out effects similar to themselves (as the philosophical adage puts it) and, consequently, all effects bear some resemblance to their causes. Accordingly, all creatures have a certain degree of similarity with the Creator, and this similarity varies according to the degree of perfection of their being.
6b) Univocity and Equivocity
Analogy is intermediate between univocity and equivocity. In a comparison, analogy entails both similarity (univocity) and dissimilarity (equivocity). In the case of the analogy of creatures with God, the similarity is minimal (although real, i.e., based on causality) and the dissimilarity is infinite. The human mind can discover something about God through the similarity between creatures and him. It is very little, but it is something really found in God; otherwise, it would not be found in the creatures, which were made by God out of nothing. We can, therefore, speak about God on the basis of the perfections found in creatures.
The perfections found in creatures cannot be attributed univocally to God because these same perfections are found in God in an infinitely superior way. Still, it is not an equivocal predication either, because these perfections are not totally different in God and in creatures—they maintain some resemblance. Therefore, the predication must be analogical—halfway between univocity and equivocity.
6c) Affirmation, Negation, and Eminence
Our analogical knowledge of God includes the ways of affirmation, negation, and eminence.
The way of affirmation is the first step in our analogical knowledge of God. It implies attributing all the pure perfections that are found in creatures (such as truth, goodness, beauty, life, and intelligence) to God. The concept of pure perfection excludes any imperfection whatsoever.
The second step is the way of negation, by which we deny that these pure perfections are found in God in the same way as they are found in creatures, whose perfections are always limited.
Consequently, it is necessary to proceed to the way of eminence: We admit that these same perfections are in God but in an ineffable and eminent way, being infinite and identified with the divine essence. These ways are not three different ways to God through creatures, but rather three consecutive stages in a rational path to God.
The pure perfections of the creatures are predicated of God in a proper sense because they are really present in him at an infinitely greater scale. The mixed perfections, however, are necessarily mingled with imperfections because they are exclusive of creatures, and can be attributed to God only in an improper or metaphorical sense.
6d) Analogical Knowledge Is True but Imperfect Knowledge
Knowledge is true when it agrees with the reality of the known object. In other words, there is true knowledge when the idea produced by the mind in the act of knowing is an accurate representation of the known object. In the case of our analogical knowledge of God, the divine perfections are the known object. This knowledge is based on the real and true likeness between the creatures’ perfections and God’s. In this case, human reason really reaches God through analogy. However, given the infinite distance between God and creatures and the infinite dissimilarity implied in the analogy between them, this type of knowledge is necessarily imperfect. We know God truly, but his essence is infinitely richer than whatever degree of knowledge we may acquire about it.
Footnotes:
1. St. Augustine, Confessions, 10.28.39.
2. Cf. CCC, 27–30, 44–46.
3. DS 3004, 3026; cf. CCC, 36–38.
4. Cf. DS 3538; CCC, 31–35.
5. Cf. ST, I, q. 2, a. 3; cf. St. Thomas Aquinas, Summa Contra Gentiles, 1.13.
6. Cf. GS, 19–21; cf. CCC, 2123–2126.
7. Cf. GS, 20.
8. Ibid.
9. Cf. DS 3475–3500; CCC, 2127–2128.
10. Cf. DS 2751–2756 for Bautain, DS 2811–2814 for Bonnetty.
11. Cf. DS 2841ff.
12. Cf. DS 3201ff.
13. Cf. CCC, 39–43.