Trinity Beyond Reason
"That three beings should be one being, is a proposition which contradicts reason, that is, our reason; but it does not from thence follow, that it cannot be true; for there are many propositions which contradict our reason, and yet they are demonstrably true. One is, that very first principle of all religion, the being of God. For, that any thing should exist without a cause, or that any thing should be the cause of its own existence, are propositions equally contradictory to our reason; yet one of them must be true, or nothing could have existed.
"All these difficulties arise from our imagining that the mode of existence of all beings must be similar to our own, that is, that they must exist in time and space, and hence proceed our embarrassments on the subject. We know that no two beings, with whose modes of existence we are acquainted, can exist on the same point and space, and that therefore they cannot be one. But how far beings whose mode of existence bears no relation to time and space, may be united we cannot comprehend. And, therefore, the possibility of such a union we cannot positively deny."