Recently I’ve been talking about the rationality of Christian (and specifically Catholic) belief in God, and how one’s mind can begin to ascend to the reality of God. It’s an imperfect ascent; God is infinite, and human reason, even at its best, is both weak and finite; but with God’s help it is possible.
Thomas begins, as Aristotle does, by reflection on the world around us. He takes for granted the existence of objective reality, and our ability to perceive and grasp it directly, or in other words he assumes that metaphysics is logically prior to epistemology. This is much disputed, and many put it the other way around, giving the question of how we know priority over the question of what we know; but personally, I regard the history of philosophy since then as a massive reductio ad absurdum, and that a belief in objective reality is the only truly rational one.
From objective reality, then, and with the aid of a very few basic principles (e.g., non-contradiction and the principle of sufficient reason) Thomas reasons to the existence of a creator God, the ultimate and first cause, who must necessarily be the source of all Being, that is, the source of all that is Good, True, and Beautiful. Thus far one can go by pure reason taken with a rational position on the nature of reality. But note that it’s a much longer and harder road than one might think from the brief sketches in Thomas’ famous Five Ways; I assure you that if you have spent no more than the five or ten minutes it takes to read them, you haven’t understood him.
So how does one rationally assess divine revelation? Some have said that it isn’t for us to assess; that we must simply accept it and move on. Historically, this point of view has been called fideism; and though it is a common Christian point of view it is not a specifically Catholic point of view. God gave us the ability to reason for a reason, and He expects us to make use of His gifts.
According to Thomas, truths come in two flavors: those we can ascertain for ourselves, and those we can know by revelation, and these sets overlap slightly. For example, God revealed the Ten Commandments to Moses as the basic moral law, but to Thomas they are also accessible to reason; and indeed the principles of the Ten Commandments are generally observed (though often in the breach) in almost every human society.
Of those things that we can know only by revelation, we cannot hope to prove them; but we can show that they make sense, and that they are not inconsistent with the other things we know, and this is Thomas’ approach in the bulk of the Summa Theologiae. And in the end, revelation depends on the character of God as He has revealed Himself to us in Jesus Christ.
Photo credit: William H. Duquette, 2015