Richard Cartwright on Trinity and Mystery
From Richard Cartwright, "On the Logical Problem of the Trinity," on-line here. Cartwright's important article is required reading for anyone seriously interested in the doctrine of the Trinity.
At this point I need to anticipate an objection. It will be said that a philosopher is trespassing on the territory of the theologian: the doctrine of the Trinity is a mystery, beyond the capacities of human reason, and hence the tools of logic are irrelevant to it. The objection is based on a misunderstanding. The doctrine of the Trinity is indeed supposed to be a mystery. That simply means, however, that assurance of its truth cannot be provided by human reason but only by divine revelation. It is to be believed "not because of the natural light of reason, but because of the authority of God who reveals it." But a mystery is not supposed to be refutable by human reason, as if a truth of reason could somehow contradict a revealed truth; on the contrary, putative refutations are supposed themselves to be refutable. Nor is a mystery supposed to be unintelligible, in the sense that the words in which it is expressed simply cannot be understood. After all, we are asked to believe the propositions expressed by the words, not simply that the words express some true propositions or other, we know not which.
Cartwright is making two main points:
1. A mystery is a doctrine that cannot be known to be true by unaided human reason, but only by divine revelation.
2. Mysteries are not supposed to be unintelligible or logically contradictory. We could say that mysteries transcend human reason, but without contradicting it. They are suprarational but not irrational or infrarational. A proposition is suprarational in this sense just in case it can be thought without logical contradiction but cannot be known by human reason alone.