Article 5 — Whether there is a number of persons in God

The fifth point of inquiry is whether there is a number of persons in God. (Parallel texts: ST I.30.1; In I Sent. 2.4; 23.4; Compendium theologiae, cc. 50, 55; Quodlibet VII, q. 3, a. 1.)

Obj. 1: And it seems that there is not. For Boethius says: that is truly one in which there is no number. (Boethius, On the Trinity 2 (PL 64:1250).) But God is most truly one. Therefore, number is not in him.

Obj. 2: It will be replied that in God there is no number simply speaking but a number of persons.

On the contrary, from a qualified statement we may always infer a simple statement, provided the qualification has not the effect of diminishing: thus, from the proposition, “there is a white man,” it follows that there is a man, but from the proposition, “there is a dead man,” it does not follow that there is a man. Now, when we say a “number of persons” the qualification does not diminish, since person is something most complete. Therefore, if in God there is a number of persons, it follows that there is number simply.

Obj. 3: Unity is opposed to number, according to the Philosopher. (Aristotle, Metaphysics 10.3, 1054a20–22.) But opposites are not in the same subject. Since, then, in God there is supreme unity, there cannot be number or any plurality in him.

Obj. 4: Wherever there is number there is plurality of units, and where there are several units there is manifold being, because the being of one unit is distinct from the being of another unit. If, then, there is number in God, there must be manifold being and manifold essence; which is clearly false.

Obj. 5: Just as unity is undivided, so is there division in number. But there cannot be division in God, since there is no composition in him. Therefore, there cannot be number in God.

Obj. 6: Every number has parts, for it is composed of units. But there are no parts in God, since there is no composition in him. Therefore, number is not in God.

Obj. 7: We should not attribute to God anything wherein the creature differs from him. Now, the creature differs from God in that it is produced in a certain number, according to Wisdom 11:21: you have ordered all things in measure and number and weight. Therefore, we should not ascribe number to God.

Obj. 8: Number is a species of quantity. But there is no quantity in God, inasmuch as if any quantitative expression were predicated of God, he would be substantially changed, as says Boethius. (Boethius, On the Trinity 2–4 (PL 64:1250–53).) Therefore, either there is no number in God, or it belongs to his substance; which is contrary to the faith.

Obj. 9: Wheresoever is number there are the qualities of number, such as perfect and diminished, multiplication and division, and the like, which result from number. But these cannot be in God. Therefore, number cannot be in God.

Obj. 10: Every number is finite. Therefore, the infinite cannot be numbered. Since, then, God is infinite, there cannot be number in him.

Obj. 11: To this it might be replied that God, though infinite to us, is finite to himself.

On the contrary, that which belongs to God in himself is truer than that which belongs to him as compared to us. If, then, God is finite to himself and infinite to us, he is more truly finite than infinite, and this is clearly false.

Obj. 12: According to the Philosopher, number is multitude measured by the unit. (Aristotle, Metaphysics 10.3, 1054a26–28; 10.6, 1057a2–4.) But God is a measure that is unmeasured. Therefore, no number is in God.

Obj. 13: In a nature that differs not from its supposit, it is impossible to have several supposits of that nature, since it is because of this that it is possible to have several men in the one human nature, that the individual man is not his own humanity; therefore, the multiplication of individuals in the one human nature is consequent upon the diversity of individual principles, which do not belong to the account of the common nature. In immaterial substances, however, wherein the very nature of the species is the subsisting supposit, there cannot be several individuals of one species. Now, in God, there is an identity of nature and supposit because the divine being itself, which is the divine nature, is subsistent. Therefore, there cannot be in God several supposits or persons.

Obj. 14: “Person” is the name of a real thing; hence, where there is not a number of realities, there is not a number of persons. Now, there is not a number of realities in God: for Damascene says that in God the Father, Son, and Holy Spirit are really one thing, though in account and in our thinking they are distinct. (John Damascene, On the Orthodox Faith 1.12 (PG 94:845–50).) Therefore, in God, there is not a number of persons.

Obj. 15: There cannot be a number of things in one without composition. Now, God is one; therefore, if in God there are several persons, which is the same as several realities, it follows that there is composition in him, and this is incompatible with his simplicity.

Obj. 16: The absolute is more perfect than the relative. Now, the absolute properties, namely, the essential attributes, such as wisdom, justice, and so on, do not constitute so many persons in God. Neither, therefore, do the relative properties, such as paternity and filiation.

Obj. 17: That which differentiates things from one another stands in relation to them as their constituent difference. If, then, the divine persons are distinguished by their relations, these latter must be the constituent differences of the persons; and consequently, there will be composition in the divine persons, inasmuch as the difference constitutes the species by being added to the genus.

Obj. 18: Things that are distinguished by specifically different forms must themselves differ specifically; thus, man and horse differ specifically as being rational and irrational. Now, paternity and filiation are specifically different relations. If, then, the divine persons are distinguished by the relations only, they must differ specifically and consequently will not be of one nature, which is against the faith.

Obj. 19: It is inconceivable that several supposits have one being. Now, in God, there is but one being. Therefore, there cannot be several supposits or persons in him.

Obj. 20: Since creation is the proper act of God alone, it must proceed from every supposit of the divine nature whatsoever. Now, it is impossible that this action, since it is one, proceed from several supposits, because one action is from but one agent. Therefore, there cannot be several supposits or persons in the divine nature.

Obj. 21: Here below, difference in properties does not make a difference in supposits: thus, one supposit of human nature is not distinct from another through the one being white and the other black but through the diversity of individual matter, which is the substance of each individual. If, then, in God there is no distinction save that which arises from relative properties, there cannot be in him a number of supposits or persons.

Obj. 22: The highest creatures are more like God than the lowest. Now, in the lowest creatures there are several supposits in one nature, while in the highest creatures, which are the heavenly bodies, there are not. Therefore, in God there are not several persons in one nature.

Obj. 23: The Philosopher says that when the whole perfection of a species is found in one supposit, there are not several supposits of that nature, and that for this reason there is but one world, because it consists of its whole matter. (Aristotle, On the Heavens 1.16–17, 276a22–277b12.) Now, the whole perfection of the divine nature is in one supposit. Therefore, in the one nature there are not several supposits or persons.

Obj. 24: To this it may be replied that the fullness of joy requires the companionship of several in the divine nature, because there is no pleasure in possessing a thing unless we share it with a companion, according to Boethius. Moreover, perfect love is to love another as oneself.

On the contrary, to depend on another for the fullness of one’s joy and love is an indication of insufficient goodness in oneself. Hence, the Philosopher says that the wicked, who find no pleasure in their own company, seek the companionship of others, while the good seek to commune with themselves, as though finding pleasure within themselves. (Aristotle, Nicomachean Ethics 9.4, 1166a23–b29.) Now, the divine nature cannot lack a sufficiency of goodness. Therefore, since one supposit of the divine nature has in himself all fullness of joy and love, there is no need to put several supposits or persons in God.

On the contrary, it is written: there are three who give testimony in heaven, the Father, the Word, and the Holy Spirit (1 John 5:7). (Cf. q. 9, a. 4, obj. 1.)

Furthermore, Athanasius (Cf. q. 1, a. 1, obj. 6.) says in the Creed: all the three persons are coeternal and coequal with one another. (Athanasius, Athanasian Creed 26 [8] (PG 28:1583).) Therefore, in God, there is a number of persons.

I answer that the plurality of persons in God is an article of faith, and natural reason is unable to investigate and adequately understand it, though we hope to understand it in heaven when we shall see God in his essence, and faith will be succeeded by vision. The holy fathers, however, being pressed by those who gainsaid the faith, were compelled to discuss this and other things that look to faith, yet humbly and reverently withal, and avoiding any pretense to comprehension. Nor is such a discussion without its use, since it enables the mind to grasp some of the truth that is sufficient to rule out errors. Therefore, Hilary says: believing this (namely, the plurality of persons in God), set forth, run, persevere; and though I may know that you will not reach, I shall acclaim your progress. He who religiously pursues the infinite, although he will never catch up with it, will progress so long as he continues. (Hilary of Poitiers, On the Trinity 2.10 (PL 10:58–59).)

In order, then, to throw some light on this question, and especially in accordance with the elucidations of Augustine, (Rather: Anselm of Canterbury, Monologion 14 (PL 158:161).) we must observe that we must attribute to God every perfection that is in created things, as regards the account of that perfection, taken absolutely, but not as regards the mode in which it is in this or that thing. For goodness or wisdom is not in God as some accident, as it is in us, even though in him there is supreme goodness and perfect wisdom.

Now, in created things nothing is found nobler or more perfect than understanding. A sign of this is that of all created things, intellectual substances are the noblest and are said to be made to God’s image in respect of their intellect. It follows, then, that understanding is in God as well as all things that belong to its account, even though it belongs to God in one way and to creatures in another.

Now, it belongs to the account of understanding that there is one who understands and something being understood. However, that which is understood through itself is not that reality the awareness of which is held through the intellect, since this is at one time only potentially understood, and it is outside the one who is understanding it, as when a man understands material realities, like a stone, an animal, or something of the kind; for nonetheless, the thing understood must be in the one understanding it, and it must be one with him. Nor is the thing understood through itself the likeness of the reality understood, through which likeness the intellect is formed for the purpose of understanding; for the intellect cannot understand except insofar as it becomes actual through this likeness, just as nothing else can act insofar as it is in potency but only as it becomes actual through some form. Accordingly, this likeness, in the act of understanding, stands as the principle of understanding, just as heat is the principle of heating something, and not as the terminus of the understanding.

Consequently, that which is understood primarily and through itself is what the intellect conceives within itself about the reality understood, whether it be a definition or proposition, insofar as these are posited as two operations of the intellect in On the Soul 3. (Aristotle, On the Soul 3.8, 431b28–432a9.) Now, this thing so conceived by the intellect is called an “interior word,” for it is signified by means of vocal speech, for the exterior spoken word does not signify merely the thing understood itself, or the intelligible form thereof, or the very act of understanding, but the concept of the intellect by the mediation of which it signifies the reality, as when I say “man” or “man is an animal.” And in this respect it matters not whether the intellect understands itself or something other than itself, since just as when it understands something other than itself it forms a concept of that reality that is then signified orally, so also when it understands its very self it forms a concept of itself that it also can express by vocal speech.

Since, then, there is understanding in God, and by understanding his very self he understands all other things, it follows that there must be in him a concept of the intellect, which, absolutely speaking, belongs to the account of understanding. And if we were able to comprehend the divine understanding, both what it is and how it takes place, just as we comprehend our own understanding, the conception of the divine Word would not surpass reason, just as neither does the conception of a human word.

We can, however, know what that understanding is not and how it is not; and thus, we are able to know the difference between the Word conceived by God and a word conceived by our intellect. For, first of all, we know that in God there is but one act of understanding and not many, as in us, for our understanding a stone is distinct from our understanding a plant, whereas for God there is one understanding whereby he understands both himself and all other things. Hence, our intellect conceives many words, but the Word conceived by God is only one.

Moreover, our intellect frequently understands both itself and other things imperfectly, whereas the divine understanding cannot be imperfect. Hence, the divine Word is perfect, representing all things perfectly, whereas our word is often imperfect.

Again, in our intellect, understanding and being are different things; therefore, a word conceived in our intellect, since it proceeds from our intellect as such, is not united to it in nature but only in the act of understanding. However, God’s understanding is his being, so the Word that proceeds from God as understanding proceeds from him as existing; and for this reason, the conceived Word has the same essence and nature as the conceiving intellect. And because that which in living things is the recipient of the nature is said to be begotten and is called a son, the divine Word is said to be begotten and is called the Son. But our word cannot be described as begotten by our intellect or as its son, except metaphorically.

Accordingly, since a word of our intellect differs from our intellect in two respects—namely, in that it is both from it and is of a different nature than it—and we have removed from the divine Word a difference of nature (as was shown), the only remaining difference is that of being from another. (Q. 8, a. 1.) Therefore, since difference causes number, it follows that the only number in God is that of relations. Now, in God, relations are not accidents; rather, each one is really the divine essence. Therefore, each of them, like the divine essence, is also subsistent, and just as divinity is the same thing as God, so too is paternity the same thing as the Father; and therefore, the Father is the same thing as God. Accordingly, the number of relations is the number of realities subsisting in the divine nature, and these realities subsisting in the divine nature are the divine persons, as is clear from the preceding article. For this reason, then, we place a number of persons in the divine.

Reply Obj. 1: By these words, (Boethius, On the Trinity 2 (PL 64:1250).) Boethius means to exclude number from the divine essence, for this is the point of his discussion.

Reply Obj. 2: Although the persons considered as subsistent do not detract from the account of number, they do so insofar as they are relations; for relative distinction is the least of all distinctions, just as relation itself of all the genera has the least being.

Reply Obj. 3: Unity and number are both attributed to God, but not in the same respect: unity in respect of the essence, number in respect of the persons; or unity in respect of absolutes, number in respect of relations.

Reply Obj. 4: Since plurality of units is caused by some distinction, if this distinction be one of being, the units must differ in being, but where the distinction is one of relations, the units that compose the plurality must differ from one another only by the relations.

Reply Obj. 5: Any distinction suffices to establish a plurality of like kind. Therefore, just as in God there is no distinction in things that are absolute—which distinction cannot exist without composition—but only a distinction of relations, so too in God there is no plurality in respect of things that are absolute but only in respect of the relations, as already stated.

Reply Obj. 6: The parts of a number are always units if we speak of the absolute number, by which we count. But if we take number as it exists in real things, then the account of whole and part is not in number except insofar as it is found in the things numbered. Now, the different relations in God are not parts, just as fatherhood and sonship are not parts of Socrates, even though he is father of one and son of another. Therefore, neither are the units of the relations compared as parts to the number of relations.

Reply Obj. 7: The creature differs from God in that it is produced in a number of essential principles. But this kind of number is not that of the persons.

Reply Obj. 8: The number which is a species of quantity is caused by a division of a continuous quantity; therefore, just as continuous quantity is a mathematical nature—because it is separated from sensible matter in its account and not in being—so also the number that is a species of quantity (which is also the subject of arithmetic), the principle whereof is the one that is the first measure of quantity. Hence, it is plain that this number cannot be in immaterial realities; rather, in them is a multitude that is opposed to the one that is convertible with being; and this is caused by a formal division, which occurs through certain opposite forms, whether absolute or relative, and such is number in God.

Reply Obj. 9: Such attributes result from the number that is the species of quantity, but this kind of number is not in God, as stated above.

Reply Obj. 10: God is infinite in the perfection of greatness, wisdom, and the like; therefore, it is written that of his wisdom there is no number (Ps 146:5), but procession in God, by reason of which there are several divine persons, does not go into infinity; for, as Augustine says in On the Trinity, the divine generation is not immoderate; (Augustine, On the Trinity 2.3, para. 5; 4.20, para. 29; 15.26–27 (PL 42:847–48; 908–9; 1092–97); cf. Against Maximinus 2.12, para. 3 (PL 42:763).) therefore, neither is the number of persons infinite.

Reply Obj. 11: God is said to be finite to himself, not that he knows himself to be finite, but because he is compared to himself as finite things are compared to us, in that he comprehends himself.

Reply Obj. 12: This is the definition of number insofar as it is in the genus of quantity, to which pertains the account of measure.

Reply Obj. 13: In created things, the individuating principles hold two functions. The one is that they are the principle of subsistence (since the common nature does not subsist by itself except in the individual), and the other is that they distinguish the supposits of the common nature from one another. But in God, the personal properties only distinguish the supposits of the divine nature from one another, while they are not the principles of subsistence of the divine essence (since the divine essence is subsistent in itself); on the contrary, the personal properties subsist by the essence; thus, paternity is a subsistent reality because the divine essence, with which it is identical, is a subsistent reality, so that it follows that as the divine essence is God, so is paternity the Father. And hence, it follows likewise that the divine essence is not numerically multiplied by reason of the multiplicity of its supposits, as happens here below. For a thing is numerically multiplied on account of that which gives it subsistence, and although the divine essence is, so to speak, individualized by itself as regards its self-subsistence, yet though it is itself one in number, there are several supposits in God that are mutually distinct through the subsistent relations.

Reply Obj. 14: If the Father, Son, and Holy Spirit differed from one another not in reality but only in account, there would be no reason why one should not be predicated of the other, just as clothing and garment may be predicated of each other; and in like manner, the Father would be the Son and vice versa, which is the heresy of Sabellius. Hence, we must reply that Father, Son, and Holy Spirit are three realities, as Augustine says, provided “reality” be taken for a relative thing; for if “reality” be taken as an absolute, then they are but one reality, as again Augustine says in On Christian Doctrine. (Augustine, On Christian Doctrine 1.5 (PL 34:21).) In this sense, we must take the words of Damascene, where he says that they are really one. (John Damascene, On the Orthodox Faith 1.12 (PG 94:845–50).) And when he says that they differ only in account, this is generally understood to mean relatively. For although a relation as compared with the opposite relation makes a real distinction in God, it does not differ, save in account, from the divine essence. Moreover, of all the genera, relation is a reality in the weakest manner.

Reply Obj. 15: In God, plurality of things is plurality of subsistent opposite relations, and this does not cause composition in God. For relation as compared to the divine essence differs not in reality but only in account. Hence, it does not make a composition with it, just as neither does goodness nor any other of the essential attributes; but if we compare it with the opposite relation, there is a plurality of realities but not a composition of them, for opposite relations as such are distinct from each other. And composition is not of just any distinct things as such.

Reply Obj. 16: The essential attributes are in no way opposed to one another as the relations are; therefore, although like the relations they subsist, they do not constitute a plurality of mutually distinct supposits, since plurality follows on distinction, and formal distinction arises from a certain opposition.

Reply Obj. 17: In God, there is no difference between what is signified through the mode of a form and what is signified through the mode of a supposit; for instance, the divine nature and God, the paternity and the Father. Hence, although the relative properties are, as it were, the constituent differences of the persons, it does not follow that they make any composition with the persons thus constituted.

Reply Obj. 18: Although the Father and the Son are not distinguished from each other except by paternity and filiation, it does not follow that the Father and the Son are, as it were, specifically different in the divine, because paternity and filiation are relations diverse in species. For these relations do not stand to the divine persons as what give species, but rather more as distinguishing and constituting the supposits. But that which stands to the divine persons as giving them species is the divine nature, wherein the Son is like the Father; for the begetter begets his like in species and not in individual properties. Accordingly, just as Socrates and Plato, even if the only difference between them as individuals were that one is black and the other white (which are specifically different qualities), would not differ themselves specifically; for that which is the species for white and black is not the species for Socrates and Plato; thus it does not follow that the Father and the Son differ specifically on account of the difference in species between paternity and filiation. And yet, in God, it cannot be said properly that anything differs specifically, since species and genus are not in him.

Reply Obj. 19: It must be wholly granted that there is not but one being in God, seeing that being always pertains to essence and especially in God, whose being is his own essence. But the relations that distinguish the supposits in God do not add another being over and above the being of the essence, because they do not make a composition with the essence, as already stated. However, every form that adds being over and above the substantial being makes a composition with the substance, and that being is itself accidental, for instance, the being of white and black. Accordingly, difference in respect of being follows plurality of supposits, just as difference of essence does in created things. But neither of these obtains in God.

Reply Obj. 20: Activity issues from the agent by reason of the form or power that is the principle of the activity; therefore, nothing prevents the one creation from proceeding from the three persons that are of one nature and power; for example, if three hot things had numerically the same heat, numerically one heating would issue from them.

Reply Obj. 21: The individuating forms in created realities are not subsistent, as they are in God; hence, the comparison fails.

Reply Obj. 22: In created realities, a multiplication of the essence follows a multiplication of supposits, but this is not the case in God; therefore, the conclusion does not follow.

Reply Obj. 23: Although the divinity is wholly and perfectly in each of the three persons according to its proper mode of existence, yet it pertains to the perfection of the divinity that there be several modes of existing in the divine, namely, such that there be one from whom, himself from no one, and one who is from another. For there would not be absolute perfection in the divine unless the procession of word and love were there.

Reply Obj. 24: This argument takes it for granted that the divine persons differ in essence. For thus the fullness of delight that the Father has in the Son would be in something extrinsic, and the Father would not have it within his very self; but because the Son is in the Father as his Word, the Father could not have full joy in his very self except in the Son, just as a man does not delight in his very self except through the concept he has of his very self.