In this post I’d like to focus on Richard’s initial argument for why God must be a Trinity of persons. Thus far in his argument he has argued for two divine persons, and now adds a further line of argument to show that God is in fact a Trinity and not a Binity of persons. Why must God be a Trinity of persons? Richard argues from his notion of perfect love.
“Greatest love cannot lack in anything.”
Perfect love requires the following.
(i) A person “wishes another to be loved as oneself.”
(ii) A person “wishes that another person be loved equally by the one whom s/he loves supremely and by whom s/he is supremely loved.”
Translation: For person a, person b, and person c, a has perfect love only if
(1.) a equally loves b, and vice versa.
(2.) a equally loves c, and vice versa.
(3.) a desires that b equally loves c, and that c equally loves b.
(1)-(3) will be jointly sufficient for a‘s perfect love if it turns out that there is a b and a c, and that all the lovin’ obtains between a, b and c as described in (1.)-(3.), especially that b equally loves c, and vice versa.
Recall that ‘equal love’ requires that the persons who ‘equally love’ have the same substance-kind. We might say the intensity (my word) of love is measured by the kind of substance that is the object of love. If I love a human, there’s a certain intensity of my love for a human; but if I love God, then my love is maxed-out because God is the most lovable being. Also, recall that Richard argued in Book 1 of On the Trinity that there can be only one divine substance. Thus, for a to love an equal, b and c, b and c must satisfy the following necessary and sufficient condition:
For divine person a, who has the one divine substance essentially, persons b and c are equal to a if and only if b and c each has the one divine substance essentially.
Notice that a divine person can love a creature ‘perfectly’, but that this love is not ‘love of an equal’ because no creature (besides Jesus) is constituted by the divine substance. So, God can “so love the world that …”, but we might say the quality of this love is fixed by the object of the love. Since divine persons are divine, love for such a person is as intense a love as possible; but love for creatures is less intense simply by reason of the kind of being that a creature is.
The argument from perfect love for a Trinity of persons continues.
(4.) If a has perfect love, then there must be a third person c, otherwise a fails to have perfect love.
(5.) If a fails to have perfect love, then either a is unwilling to have perfect love or is unable to have perfect love.
(5.i) If a is unwilling to have perfect love, then perfect love must be elsewhere. But who else besides a divine person could have perfect love essentially? Nobody. But a person who has the divine substance essentially satisfies the description of ‘the best of all possible beings’ (substances). Therefore, a person, who has the divine substance essentially, has perfect love.
(5.ii) If a, who has the divine substance essentially, is unable to have perfect love, then a does not satisfy the description of the best of all possible beings (substances). But a, who has the divine substance essentially, satisfies the description ‘the best of all possible beings’. But a person who satisfies the description ‘the best of all possible beings’ has perfect love. Therefore, a has perfect love.
(6.) Therefore, there are (at least) three divine persons.
In the next post I survey another argument that Richard employs, namely an argument from perfect happiness.