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


Dear Dr. Craig

I have been a fan of your work for about 2 or 3 years now. I used to be an atheist until one of my Christian friends directed me to your website and now I would consider myself to be struggling with atheism/scientism and Christianity. The last few days an idea has shaken up my worldview and my trust that philosophy can prove the existence of God. I think I can best sum up the idea as such.

Let's say 50,000 years ago our evolutionary ancestors had no concept of philosophy or that they did not have as an advanced/sophisticated view as we do today. Currently your philosophy, as well as Plantinga, Kreeft, Lennox and the like seem to logically deduce that God exists. My problem is what if in 50,000 years (If the human race survives that long) the human processes of deducing arguments and using logic are much better than ours today, and then they find contradictions in your argument that disprove the existence of God. Or they create better arguments against the existence of God that we currently cannot fathom with our intelligence today.

How can I trust that my mental capabilities are adequate enough to create an air-tight logical argument for the existence of God? (Which will remain as air-tight today with the current human thinking power as it will if the human thinking power develops and grows stronger.)

Your hopeful brother in Christ



Dr. William Lane Craig’s Response

Dr. William Lane Craig

Though very common, Matthew, these sorts of “What if--?” questions are really pointless. “What if I’m just a brain in a vat stimulated by a mad scientist?” “What if I’m just a body lying in the Matrix inhabiting a virtual reality?” “What if I’m being deceived by an evil god or demon?” “What if the universe is just a hologram?”

The problem with all these hypothetical questions is that there is no warrant for any of them, and so they do not constitute defeaters of our beliefs. Simply describing a hypothetical possibility does nothing to undermine one’s belief that x. You have to have some good reason to think that the hypothesis is actually true. Otherwise your belief remains undefeated.

So consider the case of your concern: “what if in 50,000 years . . . the human processes of deducing arguments and using logic are much better than ours today, and then they find contradictions in your argument that disprove the existence of God. Or they create better arguments against the existence of God that we currently cannot fathom with our intelligence today.” Is there any evidence to think that that is going to happen? You might say, “Look at the enormous progress in argumentation and logic that humanity has made in the last few thousand years!” Certainly, that does give good reason to think that progress will continue to be made. But that’s no evidence at all for the claims that contradictions in the theistic arguments will be found or that better, as yet unfathomable, arguments against theism will be found. Those are just sceptical fears. In fact, I suspect that what is more likely, given the historical pattern, is that new arguments for God’s existence will be discovered (e.g., the fine-tuning argument) and solutions will be found to problems that may presently seem intractable (e.g, the resolution of the age-old logical version of the problem of evil). You have just as much reason for optimism as for fear.

You also need to appreciate that as science progresses it’s not as though the old theories are just abandoned. Rather they are taken up and incorporated into the new (e.g., Newtonian physics’ being incorporated into relativity physics for objects moving with velocities not near the speed of light). Similarly, while advances in logic have been made (e.g., sentential logic is able to deal with inferences that Aristotelian syllogistic logic couldn’t handle), it’s not as though the old logic is just dumped. It’s still the case that if all A are B, and all B are C, then all A are C. Unlike science, logic is not dependent on empirical facts and so is less susceptible to revision. The theistic arguments I defend are based on such elementary and intuitive inference rules that there is no realistic chance of their being invalidated or found contradictory.

Perhaps more importantly, however, your question seems to be predicated on a false assumption, namely, that we need or are looking for “an air-tight logical argument for the existence of God.” That’s not right. God’s existence doesn’t need to be proven with the sort of mathematical certainty you imagine in order for belief in God to be both rational and warranted. Certainty is a will o’ the wisp that you ought not to pursue.

Moreover, I don’t think—and neither does Plantinga and, I’ll bet, Lennox—that we even need arguments proving God’s existence in order for us to know that God exists. As Plantinga has explained at considerable length, God has created us with cognitive faculties which, when functioning properly, apprehend His existence and the great truths of the Gospel, when we hear them, in a properly basic way. Thus, we are not dependent upon the vagaries of history for our knowledge that Christian theism is true and so need have no fear of what future developments might bring.

By contrast, Plantinga has argued persuasively that if naturalism is true, then we can have no confidence in our cognitive faculties. Letting R be the proposition that our cognitive faculties are reliable, N the proposition that there is no such person as God or anything like Him (naturalism), and E the proposition that we and our cognitive faculties have come to be in the way proposed by the contemporary scientific theory of evolution, Plantinga formulates the argument as follows:

1. Pr (R | N&E) is low.

2. Anyone who accepts (believes) N&E and sees that Pr (R | N&E) is low has a defeater for R.

3. Anyone who has a defeater for R has a defeater for any other belief he thinks he has, including N&E itself.

4. If one who accepts N&E thereby acquires a defeater for N&E, N&E is self-defeating and can’t rationally be accepted.

5. Therefore, N&E can’t rationally be accepted.

See Plantinga’s Where the Conflict Really Lies: Science, Religion, and Naturalism (Oxford University Press, 2011) for his defense of these premises. Thus, the person who is really in trouble when it comes to trusting his “mental capabilities” is not the theist but the non-theist!

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