The central mystery of the Christian faith is that God is three Persons in one divine nature. This is the mystery of the Trinity. A Christian is one who believes that God is this Trinity of Persons. The reason is that Christ revealed God as Father, Son, and Holy Spirit, and a Christian is one who believes in the claims of Christ.
Consider the following passages from the New Testament. In the Gospel of Matthew, Jesus says: "Everything has been entrusted to me by my Father, and no one knows the Son except the Father, just as no one knows the Father except the Son and those to whom the Son chooses to reveal him" (11, 27). Here Jesus reveals himself as the Son of the Father who has entrusted "everything" to him. No human being has ever made such a claim, nor could any mere human person make such a claim without a diagnosis of mental illness.
But this is not the only place in which Jesus reveals himself as the Son of the Father. Consider the Gospel of John: "The Father loves the Son and has entrusted everything to his hands" (3, 35). Later on we read: "...whatever the Father does the Son does too. For the Father loves the Son and shows him everything he himself does" (5, 21). Further, he says: "Anyone who has seen me has seen the Father, so how can you say, "Show us the Father?" (14, 9). But Jesus also reveals God as Holy Spirit, who is distinct from the Father and the Son: "I have said these things to you while still with you; but the Paraclete, the Holy Spirit, whom the Father will send in my name, will teach you everything and remind you of all I have said to you" (14, 25-26). Two chapters later, Jesus tells his disciples: "...unless I go, the Paraclete will not come to you; but if I go, I will send him to you....when the Spirit of truth comes he will lead you to the complete truth, since he will not be speaking of his own accord, but will say only what he has been told; and he will reveal to you the things to come" (16, 7, 13). And after his resurrection, "he breathed on them and said: Receive the Holy Spirit. If you forgive anyone's sins, they are forgiven; if you retain anyone's sins, they are retained" (20, 22). Also, Christ commissioned his Apostles to go out and make disciples of all nations and to "baptise them in the name of the Father and of the Son and of the Holy Spirit" (Mt 28, 19).
To be a son is to have a relation to someone, namely a father. To be a father is to have a relation to an offspring. Paternity and sonship are relations. But a son is of the same nature as his father. And so if Jesus is truly the Son of God the Father, then he is of the same nature as God. In other words, Christ has a divine nature. And if only God can forgive sins, and it is through the Holy Spirit that sins are forgiven, then the Holy Spirit has a divine nature. And if baptism is carried out not only in the Father's name, but in the name of the Son, and in the name of the Holy Spirit, then all three are equal in dignity. Hence, God the Father, God the Son, and God the Holy Spirit. Not three gods, but one God.
But is this reasonable? Is it not irrational to assert that God is three distinct Persons, and at the same time assert that there is only one God? Are we not violating the principle of non-contradiction in doing so? The answer to these questions is simply, no. The rest of this article is nothing more than an attempt to summarize points made in previous centuries that show that what Christians believe about the Trinity is not irrational or impossible, but perfectly in accordance with reason. Now it is impossible to attain a knowledge of the Trinity by means of natural reason alone. The Trinity is an article of faith that exceeds reason's natural capacity. But reason can go a long way in resolving what appear to be contradictions and inconsistencies in the doctrine.1
Reason can attain an indirect knowledge of God as First Cause of all that has being. And through a kind of negative method of reasoning, we can deduce a great deal about the divine essence. But reason cannot go so far as to attain the three Persons. Once the Trinity is a given, however, reason aided by faith can demonstrate that such a doctrine is neither absurd nor impossible. But before we begin, let us review some of what reason, unaided by faith, can attain to in the knowledge of the nature of God.
Note how the verbs 'to have' and 'to be' relate to the principles of essence and existence. Essence, recall, describes "what" a thing is and is expressed by the definition. What are you? The answer is, human. And a human being is a rational animal. That is what you are. But existence is not what you are, but rather what you have. You are human, but you have being. No created thing is its existence. Rather, it is what it is. The cow in the barn is bovine (essence), but it has existence. The dog in the park is canine (essence), but it has existence.
God, on the other hand, does not have a received act of existence, like you and me and everything else. If He did, He would not be God, but a creature, a created being. Rather, God is His act of existing (esse). In other words, His essence is to exist. God is pure act of existing (Ipsum Esse Subsistens).
Now anything that belongs to a thing's essence belongs to it necessarily. For example, man is essentially a rational animal. Thus, we can say that it is necessarily the case that if there is a man on the other side of this wall, he or she is rational. But whatever is outside the essence of a thing does not belong to the thing necessarily, but contingently. Thus, since blond and blue eyed do not belong to the essence of man -- otherwise all men would be blond and blue eyed -- , the man on the other side of this wall is not necessarily blond and blue eyed. He or she might be, but is not necessarily.
That is why all created things are contingent beings, and not necessary beings. Existence is not what we are, but what we have. The act of existing is not part of man's nature. For whatever belongs to a thing's nature or essence belongs to it necessarily, and so if existence belongs to you essentially, then it belongs to you necessarily. That would mean that you necessarily exist, and could not not exist, and thus always existed. But you and I did not always exist. We are aware that we came into existence in time and enjoy a received existence.
It follows that since God's essence is to be, God necessarily exists and cannot not exist, and thus always existed. Saying this does not constitute a proof of God's existence. To do that, we'd have to take a slightly different route, which we need not go into at this point. But once it has been established through reason that contingent beings depend upon a non-contingent being in order to first be and continue to be, reason can deduce a number of things about this non-contingent being.
The first thing we can deduce is that He necessarily is and is thus eternal. God never had a beginning. We can also deduce that there can only be one being whose essence is to exist, not more than one. What would distinguish two beings who are Being Itself? It would have to be something outside of what they are in common. What are they in common? Being Itself. What is it that is outside of being? Non-being, or in other words, nothing. Hence, nothing distinguishes them. And so there are not two non-contingent beings, but only one.
We also know that since God is pure act of being, He has no potentiality. And since change is the fulfillment of what exists potentially, God is unchanging. It follows from this that God is immaterial; for it is by virtue of matter that material beings are mutable, and, ultimately, matter is nothing other than potentiality. Also, if there is no potentiality in God, that means that God is not open to further perfection. God is perfect. And if He is perfect, all existing perfections found in creatures exist in God preeminently. And since intelligence is the highest perfection in man, God cannot lack intelligence.
Now, any perfection that exists in God will be identical to his act of existence. The reason is that there is no potentiality in God, and so He cannot be related to one of His perfections as potency is related to act. He is pure act. It follows that God is absolutely simple, that is, He is entirely without composition. Consider the human person for a moment. We are related to our knowledge as potentiality is related to actuality. Before we acquire knowledge, we are in potentiality towards actually attaining it. After acquiring it, we are no longer in potentiality to having it, but actually have it. Nevertheless, this knowledge is a received knowledge, or a perfection received. We are related to what we know as potentiality is related to actuality.
But as we said, there is no potency in God. Thus, His knowledge is His act of existing. He does not have knowledge. He is His knowledge. And since He is His knowledge, and He is perfect, His knowledge is perfect, which is to say He is omniscient. It also follows that since He is His knowledge, and He is First Cause of all that is, His knowledge is the cause of what is. In our case, knowledge is not the cause of the being of other things.
God is also the supreme Good. For the good is the object of desire. Now all things desire first and foremost their own perfection. But perfection (from the Latin "made through") is act. But being is act (esse is the act of being). To say that all things desire first and foremost their own perfection is to say that all things desire to be, and to be most fully. Thus, "good" is a property of being. Whatever is, is good insofar as it is -- evil is a privation of being. Now if God is pure act of being without in any way being limited by potentiality, and if good is a property of being, then God is the supreme and unlimited Good.
God knows Himself, since God is pure act of being, and a thing is knowable insofar as it is in act2, He knows Himself to be supremely and perfectly good. As the supreme and perfect Good, He rests in the possession of Himself. Hence, there is will in God; for the will is the intellectual appetite that desires and rests in the possession of the known good. Moreover, His will is identical to his act of existing, since there is no composition in God. Thus, God does not have love, rather He is His love. And since He is First Cause of all that is, His love is the cause of what is. And since love is not love unless it is freely given, God does not create by necessity. Rather, creation is free and gratuitous.
And since His intellect is His act of existing, and His will is His act of existing, and His act of existing is one, God knows and loves Himself and all things through one act of the intellect and will, not by many different acts, as is the case with us.
Finally, to say that God is Being is not to say that all existing things are divine in some way. It is impossible to share in the act of existing of any other being. For being is not a genus, like animal. Animal, or plane figure, or thing, are examples of a genus. Note that the genus is specified by a specific difference that is outside of it, as the genus animal is specified by "rational" to give us the species "man", or as plane figure is specified by the genus "three sides" to give us the species "triangle". Being cannot be a genus because there is nothing outside of it to specify it (outside of being is "non-being"). That is why being is not common, that is, it is not generic. Being is diverse, and diverse things share nothing in common. Participating in the act of existing of anything would make us one being with that thing. Yet it is this natural tendency to regard being as a universal (a genus) that is responsible for the error of pantheism -- very prevalent today as it was throughout history -- , which holds that God is ultimately all things.
Human reason can certainly deduce more from the notion of God as Ipsum Esse (Being Itself), for example, that He is the supremely beautiful and the measure of what is true. In other words, we can continue to move horizontally at this level, but this is as far as reason can go vertically, so to speak. Revelation, however, has opened up an entirely new picture that is inaccessible to unaided reason. It is as if the sky has opened, and we can reach much higher as a result. Jesus revealed God as Father, himself as the Son of the Father, and the Holy Spirit who proceeds from the Father and the Son. He has revealed that God so loved the world that He gave His only begotten Son, so that everyone who believes in him may not perish but have eternal life (Jn 3, 16).
This is a far more intimate picture, one that unaided reason could never have anticipated. Furthermore, human beings are called to enter into this intimate trinitarian life. That is why there is no understanding Christianity without the doctrine of the Trinity.
But if reason cannot attain a knowledge of the Trinity, can it at least show that such a doctrine is not irrational and impossible? We would argue, yes. The rest of this article will be devoted to doing just that.
Father and Son are terms describing persons who have a relation to one another. A relation consists in the referring of one thing to some other thing. Equality, for example, is a relation. As such, it refers one thing to another. Consider two persons of equal height. The person that is referred, namely the first person, is the subject of the relation. The person to which it is referred -- in this case the second person, is called the term. The cause of the relation, in our example, the height in which the coincidence takes place, is called the ground of the relation.
A relation is either real or logical. For example, John is really the same height as Bill, and this can of pop really has the same amount of fluid as that can of pop. Equality in these cases are real relations that exist independently of the mind. But a logical relation comes into being only in and through the activity of the intellect. Left and right in a stone, for example, are not real relations, but logical relations. They do not correspond to any real disposition in the stone, but exist only in the mind of one who apprehends the stone as right or left, because it is to the left or right of some other thing, for example the dog or cow. So too, the relation of the word "computer" to a particular device that processes information at high speeds is found neither in the word nor in the object signified. It is found only in the minds of people who have made the word stand for the computing device.
We bring up this distinction in order to point out that in God, Father, Son, and Holy Spirit are real relations, not logical ones, as some have maintained, like Sabellius, an early third century heretic who argued that Father, Son and Spirit are only nominally distinct. In other words, Father, Son, and Holy Spirit are not logical relations set up by man as a way of describing how the one God relates to human beings, for example, in three different ways. Rather, it can be said that if no human or angelic persons existed, God would still be Father, Son, and Holy Spirit, three distinct Persons in one divine nature. As we say in the Creed of St. Athanasius: "We adore one God in the Trinity and the Trinity in one God, without confusing the Persons or dividing the substance of God. For the Person of the Father is different from the Person of the Son. And both are different from the Person of the Holy Spirit".
What does it mean to be a father of a son? To be a father is to be the origin of a generation, in this case the generation of a son. A father generates a son. A son is someone who is generated by his father and is of the same nature as his father. Christ has revealed that in God, there is a generation, for he reveals himself as Son (the generated) of the Father.
This generation, however, is not a physical generation. The reason is that God is not physical. Nor is this generation one that involves change, that is, the fulfillment of what exists potentially; for there is no potentiality in God, thus no change. This generation of the Son from the Father, therefore, is eternally active, that is, it is an eternal generation that does not involve movement. How then, are we to begin to understand this? Both St. Augustine and St. Thomas Aquinas look to man's intellectual nature in order to come to some understanding of generation and procession in the Trinity. This is appropriate seeing that God created man in the image of Himself: "Let us make man in our image, according to our likeness" (Gn 1, 26). Man exists in the image of His knowledge and love, that is, he is like God in his capacity to know and will. When we look to our intellectual nature, we find that there is generation and conception, but of a spiritual or intellectual kind.3
We speak of concepts. A concept is an intellectual conception. Having a concept means having conceived an idea, which has a likeness to the thing known. When we know an object, there is a sense in which the object exists in us, but in an immaterial way. If we know the object, we have apprehended its nature. The essence of the tree, for example, exists outside the mind as a real existing nature. But when I know it, that is, when I apprehend "what" the tree is, the "what" (essence) of the tree is in me, which is why the knowledge I have of the tree is in me. In other words, the essence of the tree exists in a new way in me. It has a logical existence in the mind. It exists as universal, separated from its individuating conditions surrounding it in the phantasm (which is either a percept or image).
But what I know in knowing the object is the object itself, not the idea. The idea is that through which or by which I know the object. The intellect conceives this mental word or concept through which I know the thing itself outside the mind. This interior conception or mental word is a formal sign. Now to understand what is meant by formal sign, let us treat first what it is not. Consider the conventional sign, such as a wedding ring, a mathematical symbol like the plus or minus sign, or a stop sign. A wedding ring has come to signify marriage, but only by convention, that is, by general agreement. That is why one has to be taught what conventional signs mean or signify. The significance of a natural sign, on the other hand, is naturally understood. Smoke is a natural sign of fire, a scream is a natural sign of pain, and laughter is a natural sign of joy. No one had to decide and agree that smoke would signify fire, nor was it necessary to learn the signification of laughter. They arenaturally known. But a formal sign is something else entirely. A formal sign is a pure sign, that is, a sign whose sole function is to signify. Smoke is not a formal sign because smoke is precisely what we focus our attention on first; for I know there is fire because I see smoke. But a formal sign does not call attention to itself first. Rather, it immediately signifies something other than itself. A sensible species, a percept, and a concept are all examples of formal signs.
Take a percept, for example. Look up from this article and gaze at something in your immediate vicinity, say a television or a lamp stand. What you are perceiving is the thing itself outside of you. Now close your eyes and imagine what you just perceived. You can see the television or lamp stand in your imagination. An image is a remembered percept. While you were actually looking at the object in your immediate vicinity, the percept was there as the product of the internal sense called the unifying sense. Its sole function was to signify, that is, to refer you immediately (not mediately) to the object outside the mind. The percept is that by which you were able to perceive the object. Like the percept, a concept (which is universal, unlike the percept) is a formal sign whose sole function is to signify. Through it you and I understand the nature of the thing outside the mind.
And so a concept is a conception. This kinship between knowledge and birth evident in the word "conception" is reflected in various languages. The French word connaitre, to know, contains in itself the verb naitre, to be born. The Latin cognosco (cognition) reflects nascor, to be born. So too, the Greek gignosko, is related to gignomai (to be born). We see this in the Italian conoscere, which is allied to nascere, also 'to be born'. We speak of generating ideas or thoughts in our students. The word generate is derived from the Latin genus and the Greek genos (kind, essence), both derived from the Aryan gen, to beget or engender. The same word gen gave rise to the old English word kin (next of kind, offspring, family), which in turn is reflected in the german kennan, to know.4
What revelation has made known to us is that in God there is an eternal generation of a Word: "In the beginning was the Word: the Word was with God and the Word was God. He was with God in the beginning. Through him all things came into being, not one thing came into being except through him" (Jn 1, 1-3). The Word (Logos) is distinct from his origin ("with God"), but the "Word was God". We know that the Word is the Son and his origin is the Father: "The Word became flesh, he lived among us, and we saw his glory, the glory that he has from the Father as only Son of the Father, full of grace and truth" (Jn 1, 14).
This generation is like the generation of the word by the intellect, but is is unlike it in that the interior word conceived by the human intellect is not a person. It is also unlike the divine generation in that the generation of the interior word by the intellect is a change. The potential intellect is specified, that is, it is moved from potency to act by the active intellect that abstracts the intelligible content or essence from the phantasm (percept) and impresses it upon the potential intellect. But God is pure act of being. If the Word is God, then the Word is pure and eternal actuality, eternally generated.
The human generation of a son is like the divine generation of the Son in that what is generated is not merely a concept but a Person. It is also like the divine generation in that the son who is generated is of the same nature as the father. It is unlike the divine generation in that the person generated is a distinct being from the father. In God, the generated Son is of the same nature as the Father. But God's nature is His act of existing, and so God the Father and God the Son are not two beings, but one in being.
The Son is generated from the Father as His eternal Word. Consider that the interior word conceived by the human intellect is the essence of the thing known. The essence of a material thing is existentially neutral. It can exist outside the mind as an existing nature, and it can simultaneously exist inside the mind, having a logical or intentional existence. And yet the essence itself really is inside the mind, which is why through it I really know the nature of the object outside my mind. It's nature is in me immaterially and intentionally. My potential intellect has become what it knows immaterially. Hence, there is a likeness between the interior word and the object known through it. This is a more perfect likeness than that of an image reflected in a mirror and the thing of which the image is a reflection.
Similarly, the likeness between the Word and the Father is more perfect than that of the interior word and the object known. The reason is that the interior word exists differently in me than it does outside me. But the likeness between the Word and the Father is perfect -- for the Word is one in being with the Father.
Just as it is through the interior word conceived in the mind that we know the thing outside the mind, it is through the Word that the Father knows Himself perfectly, because the Word is the perfect image of the Father. The Word is His eternal and perfect self-understanding. The Word is the perfect expression, the perfect likeness of the Father, which would not be the case were he separated from the Father or created by the Father. And yet the Son is related to the Father as generated, and the Father is related to the Son as origin.
Now relation is one of the nine accidents of material substance. But there are no accidents in God; for He is not subject any accidental mode of being, otherwise He'd be related to it as potency is related to act, which is impossible, since He is pure act of being. Therefore, any real relation in God is identical to His act of being. This means that any real relation that exists in God is subsistent. As such, it is a Person, for God's nature is intelligent; thus, He is a Person (a person is an individual substance of a rational nature). And so paternity in God is a Person, and filiation in God is a Person.5 As was said above, these are real relations, not logical relations. The Father is really distinct from the Son because paternity and filiation are really distinct and opposite relations. And if these relations, which are opposite and distinct, are Persons, then it follows that Father and Son are really distinct Persons, yet of the same nature. In God, these distinct and opposite relations are divine and subsistent Persons.
Now the Father not only knows Himself through the Son, his Word, but the Father loves what He knows; for what He knows is supremely good and infinitely lovable. In other words, the Father loves the Son. He loves the Son with infinite and omnipotent love. The Son, who is distinct from the Father and eternally begotten of the Father, loves the Father with infinite and boundless love. The mutual love between the Father and the Son is subsistent and personal, for whatever is in God is identical to His act of being. The love between a human father and his son is unlike the love between God the Father and God the Son in that the mutual love between them is not a subsistent person. But the love between the Father and the Son is a third Person, namely the Holy Spirit.
It is a third Person because the procession of love is different than the generation of a word.6 But there are no terms for what comes forth by love and the relation that results from it.7 But the relation of the principle of what comes forth by love is called spiration or breathing. The answering relation is called a proceeding forth or procession. The Holy Spirit is this procession. And since love follows upon knowledge, the procession originates in the Father and the Son, not in the Father alone, as does the Son's generation. This spiration is thus a common spiration.8
The love that the Father has for the Son is not the Word. It is the love He has for His Word, His only begotten Son. The love that the Son has for the Father is not the Father. The Father is the object of His love. But this love, which is neither the Father nor the Son, exists in God, and whatever exists in God is God (identical to His act of being). Thus, the mutual love of the Father and the Son is a divine Person, a real relation different than filiation. For the Son proceeds from the Father as Word, but the Holy Spirit proceeds from the Father and the Son as Love. Hence, The Creed of St. Athanasius:
The Father was made by no one: neither created nor generated. The Son is from the Father: not created, but generated. The Holy Spirit is from the Father and the Son: not made, not created, not generated, but proceeding. There is one Father, therefore, not three fathers. And there is one Son, not three sons. And there is one Holy Spirit, not three spirits.
To love is to will good, either for oneself or for another. It also includes resting in the possession of the good. The object of the will is the good, and so the will naturally loves the good. But a person of intelligence and will does not necessarily choose what is best for himself, nor does he necessarily will the good of another. His love -- either for himself or for another -- may be deficient. But the greatest achievement of love is to love other human persons as another self. The perfection of this kind of love is supernatural charity (caritas).
Because I can know the other person as another self, for example, that he is of the same nature as myself, that he is a person who also naturally seeks his own perfection, etc., I have the ability to will what is best for him as another self. I am not bound by nature to pursue my own good to the exclusion of the good of another. I necessarily will my own happiness, but a genuine love for another will mean that I wish happiness befall him or her. But if my understanding of what constitutes happiness is distorted, so too my love for myself and for others will suffer the same flaw. A rightly ordered love prefers the greater good to the lesser good. The greatest love wills that the other enjoy the greatest good, and thus the greatest possible happiness. It wills that the happiness of knowing and loving God befall another.
This most selfless of loves involves a kind of exit-of-self, or an ability to become another. In love, I wish that the other be more fully. I will good for him not for my sake, but for his sake. Thus, when I know another person, he exists in me as known; but when I love another person, I exist outside myself as him, willing that he possess and delight in the good. And so love, above all things, enlarges the human person. Loving the other as another self expands us beyond ourselves such that his good becomes my good, and his joy becomes my joy. We are always finite, but as we grow in love, we become larger and increasingly like God, who is boundlessly large, but without size. By growing in love, we can forever approach a likeness to God.
But the one who will not love the other as another self, but only as a means to himself, does not expand and enlarge but contracts. He is an egoist who remains small and at the very center of his world.9 But genuine love is expansive. It longs to share its own happiness with another. There is nothing better than to love God under the aspect of friendship and wish that others benefit equally from such a friendship. In other words, there is nothing better than charity.
Now, we know through reason that God is perfect and supremely good. If God is perfectly good, and there is nothing more perfect than charity, then there is charity or perfect love in God. In fact, we can say that God is Love (1 Jn 4, 8), since whatever exists in God is identical to his act of being.
But no one can be said to have charity on the basis of his own private love of himself. It follows that where there is a plurality of persons lacking, charity does not and cannot exist. Hence, there must be a plurality of persons in God.10
We might raise an objection at this point, namely, that this does not show that in God there is a plurality of persons, but merely that creation exists as the object of divine charity. But this does not work. For it would imply that God is not sufficient unto Himself and thus needs to create in order to acquire the perfection of charity. Nor is creation sufficient, because creation cannot have any perfection that it does not receive from God. Thus, the idea that God would create something in order to acquire something for Himself is absurd.
Also, God cannot have a supreme charity for a created person, because such a love is disordered. To draw a simple analogy, consider a person who loves his pet rock like he should love his own child. He sleeps with it, eats with it, waters it, registers it for school, etc.,. Such a love is disordered, for it is not proportionate to the nature of a rock. Some people have such a disordered love for animals, in particular those who hold that non-rational animals have an inalienable right to live and not be slaughtered to serve the needs of man. Such love is not proportionate to the nature of the animal, who in this case is loved as a human person ought to be loved, that is, as an end in itself.
So too in God, charity would be disordered if He loves supremely someone who should not be supremely loved -- and only God should be supremely loved. Now if God is supremely good, He is supreme Love, and the perfection of love requires a plurality of persons. For as long as anyone loves no one else as much as he loves himself, he has not reached the perfection of charity, and if God loves no one else as much as he loves himself, he has not the supreme level of charity, which is to love supremely someone who ought to be loved supremely, namely someone of the same nature as God.
Moreover, nothing is more pleasing than charity. The more we learn to love another as another self and grow in that love, the larger we become -- for I begin to exist as him, and as her, and whoever else I choose to love. In other words, I begin to exist more fully. But happiness is fullness of being. The more I will that others share equally in the good that I love, the happier I become. As he begins to possess and enjoy that good, I rejoice because I have begun to exist as him. Through this transportation of love, his good has become my good.
God cannot but possess a perfect and supreme happiness that suffers no deficiency, because he is the supreme good. Now, it is impossible that there be lacking in God either one who can show charity or one to whom charity can be shown; for there are a plurality of Persons in God. And it is characteristic of love to wish to be loved much by the one you love much. It follows that love cannot be entirely pleasing if it is not mutual. But in mutual love, it is necessary that there be one who gives love and one who returns love. Thus, if God is supremely happy, there must exist in God a mutual exchange of love between Persons of the same nature.
Richard also confirms his conclusions by focusing on the fullness of divine glory. What is more glorious, he asks, and what is more magnificent than to have nothing that one does not want to share? In God, there can be no miserly holding back or inordinate squandering. The fullness of glory requires that there be not lacking a sharer of glory. And if this is what God wills, it cannot but be the case, since God is omnipotent. And if His omnipotent will is unchangeable, He has willed a sharer in His glory for all eternity. Thus, it is necessary that an eternal Person have a coeternal Person who eternally shares in the fullness of the divine glory.
And of course supreme charity demands equality of persons. The nature of love is such that it is not sufficient if the one being loved supremely does not return supreme love. A love received that is not returned is dead, as a seed that is sown but does not bear fruit is dead. But to return supreme love requires one equal in supremacy.
But love not only demands a plurality of persons. It demands no less than three persons. All this is implied in what we have reasoned so far. My very existence is a gift. It is a sharing in the goodness of being. As a human person, I share in being more profoundly than does a brute animal. And yet my existence is understood by me to be received. A gift given gratuitously and received has love at its origin; for to love is to will and impart to another what is good. If I have truly learned to love, I will choose to share the goodness that has been communicated to me, that is, to communicate it to another as much as I am able to. Hence, Richard says: "Certainly in mutual and very fervent love nothing is rarer and more magnificent than to wish that another be loved equally by the one whom you love supremely and by whom you are supremely loved"11
It follows that in God, the one who loves supremely and who wills to be loved supremely delights in the eternal actualization of that will, namely in the attainment of that willed love. One cannot be said to have attained the perfection of love if he cannot take pleasure in the sharing of his joy. Thus, it is a sign of tremendous weakness not to be able to allow a sharing of love and conversely, a sign of great perfection to be able to allow a sharing of love. Great it is to allow it, greater still to undertake it with rejoicing; but greatest to search for it with longing.12
Now in those who are mutually loved, the perfection of each requires a sharer of the love that has been shown to them. For if he does not will what perfect goodness demands, he does not achieve the fullness of goodness. But God is perfect goodness, and so the divine Persons will a sharer of the supreme love mutually received. If they will it but it cannot be done, then there is a deficiency of power in God, which is impossible.
And so the Father loves the Son supremely, and the Son receives and returns that love supremely, that is, he loves the Father in return. But in receiving that love, He wills to share it equally. The Father receives the supreme love of the Son and with a will identical and omnipotent wills to share it equally. But to have it shared equally requires a third divine Person. That love, which the Father and the Son will to share, is that Person. They will that the Person who shares in that love be the fullness of that love, of which there is nothing greater. The third Person must be worthy of supreme love, hence He must be divine, that is, one nature with the Father and the Son. Hence, the Holy Spirit is the mutual divine and personified love between the Father and the Son.
There is much more that can be considered and other angles from which to examine this doctrine. But if we glance at the entire hierarchy of being in the physical universe, we discern various kinds of emanation or procession at all levels of the hierarchy and a gradual interiorization thereof. For example, things at the mineral level are not alive; for a living thing moves itself from within itself, but a non-living thing is moved by virtue of an extrinsic principle, for example another rock, or the wind, etc.,. And so what emanates from a moving rock is a likeness of motion, imparted to another non-living thing, or an impression left in some external thing, such as the earth. The effect has a likeness to the cause, but it is entirely external to the cause.
As we move up to the vegetative level, we discern a more interior emanation. The plant reproduces its like from within itself, but the seed of that likeness proceeds outward and into the ground, and the development and complete actualization of the offspring takes place outside the parent plant. Moreover, the process begins outside the plant with nutrition, at the level of the roots. Higher up on the scale, we notice that reproduction in some animals has become somewhat more interior. Gestation takes place within the animal. The offspring is nurtured within, but is born to exist without. But the specific emanation belonging to sentient life occurs on the level of perception -- for an animal is a living sentient creature. I refer to the emanation of the percept by which the animal perceives the object outside of it, without that object or animal changing substantially. This kind of knowledge, however, is imperfect because material things are not capable of perfect self-reflection, and sensation is intimately tied up in matter; for we do not sense ourselves sensing. But in man we find the generation of the interior word by which he knows the nature of the thing outside of him without undergoing any substantial change and without the object of his knowledge undergoing change. The emanation of verbal communication presupposes this more interior conception. And in this kind of knowledge, unlike sense knowledge, the knower achieves total self-reflection, which is why a person knows himself knowing and sensing, and knows that he knows. In knowing himself, man's essence exists in him intentionally. Hence, he is present to himself through this word. He can talk to himself, as we often do when we are alone. And so even in us, we experience a kind of plurality that is an echo of the trinitarian plurality.
As we climb the hierarchy, we discern that generation becomes increasingly interior, and so it is reasonable to conclude that the angelic intellect has an even greater likeness to God than does the human intellect. Angelic knowing does not begin externally, that is, with sensation, as does human knowing, but is from beginning to end entirely interior. But in God, the generation of the Word and theprocession of love is entirely interior, eternal, and existentially perfect. Thus even a bird's eye glance at the hierarchy of material being hints at what revelation fully discloses.
Our destiny, according to what has been revealed in the Person of Christ, is to enter fully into the life of the Trinity. That life begins with the life of supernatural charity. Our purpose here is to begin the process of self-expansion through the transportation made possible by supernatural charity. Everything having to do with the life of the Church is ordered to this end. In Baptism we die to our old life, which was slavery to the constriction of sin and self-negating egoism. We enter into the tomb of Christ in order to rise with him to the new life of grace, that is, to the life of faith, hope and charity, given in baptism as sheer gift. In Confirmation we are sealed with the Holy Spirit of the Father and the Son and are given the power to desire above all things that God be loved and glorified and that the blessing of salvation befall others. In the Eucharist we are given the very substance of Christ and are joined intimately to him, body, blood, soul and divinity. Matrimony is a sign of the love that Christ has for hisbride, the Church, for whom he gave up his life that she might enter into the eternal life of the Trinity. The very precepts and requirements of the Christian moral life are nothing other than the full implications of the life of charity. Actions condemned by the Church are simply instances of choices that are incompatible with charity and our intratrinitarian destiny. It is not these prohibitions that limit us, but those very choices which are prohibited.
All this, of course, needs to be explicated more fully. But it all begins and ends with the Most Holy Trinity, the Father, and the Son, and the Holy Spirit. Amen.
1 St. Thomas writes: "It is impossible to attain to the knowledge of the Trinity by natural reason. For, as above explained (12, 4, 12), man cannot obtain the knowledge of God by natural reason except from creatures. Now creatures lead us to the knowledge of God, as effects do to their cause. Accordingly, by natural reason we can know of God that only which of necessity belongs to Him as the principle of things, and we have cited this fundamental principle in treating of God as above (12, 12). Now, the creative power of God is common to the whole Trinity; and hence it belongs to the unity of the essence, and not to the distinction of the persons. Therefore, by natural reason we can know what belongs to the unity of the essence, but not what belongs to the distinction of the persons. S.T. I. Q. 32. a. 1. [Back]
2 A thing is knowable insofar as it is in act. For example, pure potentiality is unknowable in itself. One cannot know that which is not actually anything. A material thing, because it is a unity of potency and act (matter and form), is not entirely transparent to the human intellect. The active mind must abstract the essence from the individuating conditions surrounding the phantasm to render the thing actually intelligible. Nevertheless, the essence of a material thing includes matter, which is why even when apprehended by the mind, we still do not fully know the essences of material things, which is evident in our imperfect definitions. There remains an opacity that is the result of the potentiality of matter. [Back]
3 St. Thomas writes: "Intelligent substances, the noblest of creatures, express themselves through knowledge and love. Thus they bear the image of the uncreated Trinity. Their own thoughts and their loves, however, are not persons; their understanding and affections are not their substance, but qualities about them. Only with God is understanding and loving his very self, only with him are his Word and Love persons. " Disputations, X, de Potentia, I. [Back]
4 See Larry Azar. Man: Computer, Ape, or Angel. Massachusetts: The Christopher Publishing House, 1989. pp. 185-186. [Back]
5 "It may be said that God has a rational "nature," if reason be taken to mean, not discursive thought, but in a general sense, an intelligent nature. But God cannot be called an "individual" in the sense that His individuality comes from matter; but only in the sense which implies incommunicability. "Substance" can be applied to God in the sense of signifying self-subsistence. There are some, however, who say that the definition of Boethius, quoted above (1), is not a definition of person in the sense we use when speaking of persons in God. Therefore Richard of St. Victor amends this definition by adding that "Person" in God is "the incommunicable existence of the divine nature." S.T. I. Q. 29. a3.ad 4. [Back]
6 "That which proceeds by way of intelligence, as word, proceeds according to similitude, as also that which proceeds by way of nature; thus, as above explained (27, 3), the procession of the divine Word is the very same as generation by way of nature. But love, as such, does not proceed as the similitude of that whence it proceeds; although in God love is co-essential as being divine; and therefore the procession of love is not called generation in God. S.T. I. Q. 30. a1.ad 2. [Back]
7 "For as when a thing is understood by anyone, there results in the one who understands a conception of the object understood, which conception we call word; so when anyone loves an object, a certain impression results, so to speak, of the thing loved in the affection of the lover; by reason of which the object loved is said to be in the lover; as also the thing understood is in the one who understands; so that when anyone understands and loves himself he is in himself, not only by real identity, but also as the object understood is in the one who understands, and the thing loved is in the lover. As regards the intellect, however, words have been found to describe the mutual relation of the one who understands the object understood, as appears in the word "to understand"; and other words are used to express the procession of the intellectual conception -- namely, "to speak," and "word." Hence in God, "to understand" is applied only to the essence; because it does not import relation to the Word that proceeds; whereas "Word" is said personally, because it signifies what proceeds; and the term "to speak" is a notional term as importing the relation of the principle of the Word to the Word Himself. On the other hand, on the part of the will, with the exception of the words "dilection" and "love," which express the relation of the lover to the object loved, there are no other terms in use, which express the relation of the impression or affection of the object loved, produced in the lover by fact that he loves -- to the principle of that impression, or "vice versa." And therefore, on account of the poverty of our vocabulary, we express these relations by the words "love" and "dilection": just as if we were to call the Word "intelligence conceived," or "wisdombegotten." S.T. I. Q. 37. a1. [Back]
8 "The procession of the Word is called generation in the proper sense of the term, whereby it is applied to living things. Now the relation of the principle of generation in perfect living beings is called paternity; and the relation of the one proceeding from the principle is called filiation. But the procession of Love has no proper name of its own (27, 4); and so neither have the ensuing relations a proper name of their own. The relation of the principle of this procession is called spiration; and the relation of the person proceeding is called procession: although these two names belong to the processions or origins themselves, and not to the relations. S.T. I. Q. 28. a4. [Back]
9 Russian Philosopher Vladimir Solovyov writes: "The meaning of human love, speaking generally, is the justification and salvation of individuality through the sacrifice of egoism. The falsehood and evil of egoism by no means consist in the fact that the egoist values himself too highly, credits himself with absolute significance and infinite worth. In this he is correct, because every human subject, as an independent center of living powers, as a potentiality of infinite perfection, as a being capable in consciousness and in his life of accommodating absolute truth -- every person, as such, possesses absolute significance and worth. In every human being there is something absolutely irreplaceable, and one cannot value oneself too highly. (In the words of the gospel: "What shall a man give in exchange for his soul?) Failure to recognize one's own absolute significance is equivalent to a denial of human worth; this is a basic error and the origin of all unbelief. If one is so faint-hearted that he is powerless even to believe in himself, how can he believe in anything else? The basic falsehood and evil of egoism lie not in this absolute self-consciousness and self-evaluation of the subject, but in the fact that, ascribing to himself in all justice an absolute significance, he unjustly refuses to others this same significance. Recognizing himself as a center of life (which as a matter of fact he is), he relegates others to the circumference of his own being and leaves them only an external and relative value." The Meaning of Love. London, Floris Books. pp. 42-44 [Back]
10 St. Thomas writes: "Although the angels and the souls of the saints are always with God, nevertheless, if plurality of persons did not exist in God, He would be alone or solitary. For solitude is not removed by association with anything that is extraneous in nature; thus anyone is said to be alone in a garden, though many plants and animals are with him in the garden. Likewise, God would be alone or solitary, though angels and men were with Him, supposing that several persons were not within Him. Therefore the society of angels and of souls does not take away absolute solitude from God; much less does it remove respective solitude, in reference to a predicate. S.T. I. Q. 31. a3. ad 1. [Back]
11 Richard of St. Victor. Book Three of the Trinity. ch. XI [Back]