The following argument, like the other arguments in this section, prove or give evidence for the existence of the Christian God specifically ( and rules out the truth of other monotheisms (Judaism and Islam). The argument I’m going to present comes from Richard Swinburne’s popular work Was Jesus God?. We can start by assuming the existence of a generic monotheistic God implied by the arguments of natural theology (or the various arguments for the existence of God).
Divinity implies perfect goodness
Perfect goodness implies being perfectly loving
Perfect love is a love between equals
Therefore, God will exist as a plurality of persons
Love between two persons is inferior to love between three persons. (Love between two persons can be selfish and constricted in a way that love between three cannot be).
The quality of love relationship between more than three persons is either redundant or inferior to love between only three.
Therefore, God exists as three persons.[ii]
Why should love be a necessary component of goodness and why should perfect love be a love between equals? That love is a necessary component of goodness can only have support from our moral intuitions. We recognize that love, at least in the form of goodwill and benevolence, is an essential component of a moral life.
The absence of it would thus imply an immoral life and someone who is completely alone is incapable of benevolence. However, can one not be benevolent at heart, but simply have no opportunity to express it? For example, one can say that God has always been just, but didn’t always express his justice. Before the creation of the world, God didn’t act on his just nature, because he hadn’t yet judged anybody (at least as far as we know). However, that doesn’t mean he wasn’t just. Can’t we say that God had a benevolent nature, but just didn’t express it?
The crucial point here is that most moral qualities (perhaps even all of them) require a community within which to come about. Justice, love, kindness, patience, even chastity and fidelity, require a community in order to be manifested. Without a community, most of God’s goodness would lie “dormant”. Thus, God would perhaps still be good, but he wouldn’t be perfect, or maximally good. His glory would be diminished. Why does God’s goodness need to be manifested in order for him to be perfect? Goodness is not goodness unless it has being. If goodness is dormant in God’s nature, it lacks existence. It exists in some sense, but it has no significance, or no consequence. Goodness means next to nothing if it is never expressed, much like food that is stored and never eaten. It might as well not be there. However, if God expresses his goodness once the earth is created, doesn’t it have significance then? The significance of God’s goodness would then be finite and impermanent, because it would only be expressed at certain times rather than eternally. If God is to be maximally good, the significance of his goodness must be maximal as well (that is, infinite). But why must perfect love be a love of equals? Swinburne contends that a love like parental love, which is not the love of equals, is only valuable because, the parent is trying to turn the child into an equal.[iii] Without that goal, parental love would not be love at all. Arguably, perfect love exists between individuals only when it is perfectly reciprocated and not one-sided (as parental love often is). A child is incapable of reciprocating parental love, as much as any creature of God would be incapable of perfectly reciprocating his love, both because of the creature’s finitude and because it would probably lack the moral perfection of divinity.
We still have to address why there should be three members of this divine society. Why not two? Why not a thousand? Swinburne states the objection thus, “Do not these arguments suggest that there should be more than three divine persons, perhaps an infinite number?”[iv] Swinburne answers the objection by saying that the good achieved by adding a third divine person is unique, and that no additional unique best action is achieved by adding a fourth member or a fifth etc. To put it another way, a fourth, fifth or sixth member of the Trinity would be redundant as far as goodness is concerned. Whatever good they could achieve has already been achieved in adding the third member. Can’t we say “the more the merrier” and that the goodness of the community increases with its numbers? I don’t think this is the case. The more persons there are, the less intimate the relationships become. Also, the goodness achieved through a community can be equally well achieved through three as through a hundred. The virtues that we looked at in the last post, that require a community to be expressed, can be just as adequately expressed in a community of three as in a community of a thousand. No virtue, and perhaps especially not a virtue like love, increases in proportion to the numbers within a community. Neither love, nor any other virtue, is quantitative. The “amount” of love that can be achieved among a thousand members can equally be achieved among three. Indeed love can probably be better achieved through three members than through a thousand. So we know that real goodness and love requires community, but by ontological parsimony ( or Ockham’s razor) we should not multiply entities beyond what is necessary and we have just seen that adding persons beyond three is unnecessary. So why can there not be only two members? Can the goodness of a community not be expressed equally well in two? Swinburne answers: “A twosome can be selfish. A marriage in which a husband and wife are interested only in each other and do not seek to spread the love they have for each other is a deficient marriage. The love of the Father for the Son must include a wish to cooperate with the Son in further total sharing with an equal…”[v]
Can a threesome not be equally selfish? In a human context, it could undoubtedly be. When three people are friends, but do not share their friendship with any other, and exclude others who might be a part, then it is selfish. But the context here is quite different. The Trinity is obviously not acting to exclude other divine persons. The adding of a third member adds a particular type of love to the divine community. It is a love in which two persons cooperate in order to love someone else, rather than two persons only loving each other alone. If a fourth of fifth member is added, the relation would only be duplicated, but no unique quality would be added that has not already been added: the co-operative sharing of love. Cooperating in loving another is a completely unique relationship, different from merely loving another. Adding more divine persons would only increase the numbers involved in cooperating in loving them, but would not add a unique kind of love. “Bringing about cooperating in sharing with a fourth person is not a qualitatively different kind of good action from bringing about cooperating in sharing with a third person.”[vi] In order to put this in another way (and somewhat more confusingly) Swinburne references Richard of St Victor as saying, “bringing about the Spirit as well as the Son would provide for each divine person someone other than themselves for every other divine person to love and be loved by.” To seal the deal, Swinburne adds a further, and more logically coercive point. He contends that a fourth divine person would not be a necessary being, because it would not be the necessary consequence of an ontologically necessary being (the Father). Because the adding of a fourth person is not qualitatively different from adding a third, the Father is only logically “obligated” to cause two other divine persons. Thus, leaving divine society at three is (for the sake of argument) equally good to adding a fourth. However, there is no “obligation” on the Father to add a fourth and thus its existence would not be a necessary consequence of the existence of the Father (whereas the existence of the Son and Holy Spirit is a necessary consequence). This means that there cannot be a fourth (or fifth or sixth) divine person, because it would not be a necessary being and so it would not be divine.
[i] A Joubert, Richard Swinburne’s Argument for the Trinity, Apologetics Canada, June 4, 2015, https://www.apologeticscanada.com/2015/06/04/richard-swinburnes-argument-for-the-trinity/
A Joubert, Richard Swinburne’s Argument for the Trinity (Pt. 2), Apologetics Canada, July 7, 2015,
[ii] Richard Swinburne, Was Jesus God? (New York: Oxford University Press, 2008) 28
[iii] Ibid., 28
[iv] Richard Swinburne, Was Jesus God? (New York: Oxford University Press, 2008) 33