NOTE: This proposal is being submitted to both ETS and EPS.
While not accepting the more controversial aspects of his argument, J. P. Moreland and William Lane Craig embrace one feature of Richard Swinburne’s natural theological argument for the Trinity: that mutuality is an essential requirement of love. Accordingly, God’s being essentially all-loving entails that any “other” who is necessarily a recipient of the divine love must be internal to God’s own being. From this Moreland and Craig conclude that God must be multipersonal, but not that God must be precisely tripersonal (1).
Building on the aforementioned work, my paper attempts to supply a successful natural theological argument for the Trinity by furnishing and defending two missing premises. First, genuine love (understood as agapē) entails an absence of personal possessiveness. For any persons X and Y to genuinely love each other, their relationship cannot be construed such that only X can be the source of love for Y and only Y can be the source of love for X (2). Here we can make an a fortiori argument. Any human relationship so construed—even if neither X nor Y is being deliberately selfish—leaves both X and Y unfulfilled, rendering their relationship de facto or ontologically possessive in an unhealthy sense. Now suppose that the divine being contained only two persons (say, the Father and the Son). Even though neither the Father nor the Son would be deliberately selfish, the ontological reality is the same as though they were. As the paradigm of love, God cannot be so ontologically constituted. For if God were so constituted, then God would not be a maximally great being, as we could conceive of a being greater than it. This first premise therefore requires that God be comprised of at least three persons.
Second, any divine person must exist necessarily, not merely contingently. Love has two essential requirements: the positive requirement of mutuality and the negative requirement of non-possessiveness. Three agapically inclined persons are necessary and sufficient to fulfill the essential requirements of love, rendering any additional persons contingent. Therefore, there can only be three divine persons comprising the one God.
NOTES
(1) Richard Swinburne, The Christian God (Oxford: Clarendon, 1994), 170–79; J. P. Moreland and William Lane Craig, Philosophical Foundations for a Christian Worldview, 2nd ed. (Downers Grove, IL: IVP Academic, 2017), 593.
(2) This point is anticipated but not developed in Swinburne, Christian God, 175.