This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.


Dear Dr. Craig,

I would consider myself agnostic but have a question regarding the probability of God as accepted by the majority of the Christian community: Aren't the odds of a triune god beyond astronomical? To accept that there is an omnipotent, eternal being is difficult enough, but three separate beings that possess this nature? The term "mind boggling" doesn't even begin to describe the unlikelihood ... Thanks!


United States

Dr. William Lane Craig’s Response

Dr. William Lane Craig

Thanks for your question, Steve! Before I address it, let’s be sure we state accurately what the doctrine of the Trinity is. It is not the doctrine that there are “three separate beings that possess this [divine] nature.” That would be polytheism. Christians hold that there is one tri-personal God.

Now this is admittedly mind-boggling. But don’t equate being mind-boggling with being improbable. Quantum mechanics is mind-boggling, but that doesn’t imply that it is improbable as an account of the physical world. We live in a universe that is so mind-boggling as almost to defy comprehension!

Moreover, I have defended a sort of probability argument for the claim that God is not just one person. It goes like this: God is by definition the greatest conceivable being. As the greatest conceivable being, God must be perfect. Now a perfect being must be a loving being. For love is a moral perfection; it is better for a person to be loving rather than unloving. God therefore must be a perfectly loving being. Now it is of the very nature of love to give oneself away. Love reaches out to another person rather than centering wholly in oneself. So if God is perfectly loving by His very nature, He must be giving Himself in love to another. But who is that other? It cannot be any created person, since creation is a result of God’s free will, not a result of His nature. It belongs to God's very essence to love, but it does not belong to His essence to create. So we can imagine a possible world in which God is perfectly loving and yet no created persons exist. Moreover, contemporary cosmology makes it plausible that created persons have not always existed. But God is eternally loving. So created persons alone are insufficient to account for God's being perfectly loving. It therefore follows that the other to whom God’s love is necessarily directed must be internal to God Himself.

In other words, God is not a single, isolated person, as unitarian forms of theism like Islam hold; rather God is a plurality of persons, as the Christian doctrine of the Trinity affirms. On the unitarian view God is a person who does not give Himself away essentially in love for another; He is focused essentially only on Himself. Hence, He cannot be the most perfect being. But on the Christian view, God is a triad of persons in eternal, self-giving love relationships. Thus, since God is essentially loving, the doctrine of the Trinity is more plausible than any unitarian doctrine of God.

Finally, when we ask about the probability of a hypothesis, we must always ask, probable relative to what? Even if we think that the prior probability of the doctrine of the Trinity is low, still its posterior probability, after the introduction of new evidence, may not be low at all. The evidence in this case is the person and work of Jesus of Nazareth. He makes all the difference. The earliest Christians were Jews who were committed heart and soul to the doctrine that “The Lord our God is one Lord” (Deuteronomy 6:4). Only the most forceful considerations would have led them to adjust Jewish monotheism to accommodate a plurality of divine persons. It was trying to make sense of who Jesus was that compelled them to recognize somehow the diversity of divine persons.

It is the same for us today. Who do you think Jesus was or is? How do you make sense of his sublime life and teaching and, especially, of his death and resurrection? Thoughtful consideration of that question may lead you to acknowledge his divinity and so make a Trinitarian view of God seem—not less mind-boggling—but perhaps less improbable to you.

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