Deductive and Inductive Knowledge of God

The answer to this question all depends on what you mean by proof and what it means to prove. If you mean to come up with a deductive argument that will lead in an air-tight way to the conclusion God exists, the answer is no.

A deductive proof is one in which the conclusion must be true based on the premises. If, for example, I say, "All stones when released fall toward the earth," and then add, "What I'm holding is a stone," these statements together lead with absolute certainty to the conclusion, "What I am holding, if I let it go, will fall toward the earth." Another example is the familiar, "All men are mortal," "Socrates is a man," therefore, "Socrates is mortal." Both of these conclusions, one about a stone and the other about a man, are not open to challenge.

The difficulty with trying to come up with this kind of proof for the existence of God is that not everyone agrees on premises that, if taken together, inexorably lead to the conclusion God exists. But there's another kind of proof, one that has more to do with probability, with what makes one conclusion (inference) more likely than another.

Suppose I tell you that a lake at the equator in South America froze over. If I further said that the water was at sea level rather than high in the Andes, you'd almost certainly be skeptical. You might be inclined to think my knowledge of physics was astoundingly deficient. Or, perhaps, that I needed to see a doctor.

But if you later heard on the news that a report just came in about a lake frozen over at sea level in Ecuador, you might be less skeptical. And, if you then came across a trustworthy report about scientists having discovered that, for unknown reasons, water at sea level near the equator occasionally freezes, you'd be less skeptical still. What I told you might now seem a lot more credible.

Francis Bacon (1561-1626) substantially launched modern science by emphasizing the importance of inductive reasoning, of coming to a general conclusion based on specific observations. Many of the conclusions we come to in life, including those having to do with God, have this character. They are conclusions we reach based on acquiring what we take to be new information. Often, we begin with a belief of some kind--an assumption about the way things are--and then come across something that either supports or calls this belief into question. A Christian looks up at a star-filled night sky and is awed by God's handiwork. An atheist gazes into the same dark sky and perceives only vast expanses of frozen space, sprinkled with tiny lights, destined someday to go out.

It is worth noting that (St.) Thomas Aquinas (1225-1274) probably never intended his five ways to serve as hard (deductive) proofs of God's existence. Just about everyone in the thirteenth century believed in the existence of God, and if they didn't, they were prudent enough not to say so. Thomas principally wanted to strengthen the faith of believers.