Yes, my students too are always quite puzzled—and often worried that I mean to undermine their faith—when I tell them there are some things even God can’t do. In my Theology course the issue first arises when, in lecturing on the doctrine of creation ex nihilo, I underscore the important distinguo between two modes of necessity: extrinsic and intrinsic.

While it’s true, I explain, that God is extrinsically free in the act of creating, since He’s subject to no force or authority “outside” Himself, He’s nonetheless intrinsically obliged to create. He cannot but act in accord with His nature, and it’s in His very nature to be the Creator. God can therefore no more not create than He can lie or commit deicide. For all such actions entail contradiction, and as St Thomas says, “Nothing which implies contradiction falls under the omnipotence of God” (Summa Theologica, Part I, Question 25, Article 4).

But wait! my young charges counter. Why should mere contradictions prove to be such a problem in Heaven? Surely God can suspend the law of non-contradiction, in just the same way that He’s able to suspend other laws whenever He works a miracle.

Even though it’s mainly Christian students I teach—most of whom take the Bible seriously and who are therefore firm in their conviction that “the Logos was God” (John 1:1)—pointing out that the English “logic” is derived from the Greek logos usually doesn’t get me very far! So what I do instead, and I recommend you consider this strategy, is to ask them three questions of my own:

1. If God did “suspend” the law of non-contradiction, would it be false to say that He had not suspended it?

2. If it would be false, wouldn’t God still be acting in conformity with the law?

3. If it would not be false, then wouldn’t the law still operative?

It can take some minutes, but as soon as the smiles (or grimaces) of recognition begin showing up on a few faces, I step back from the reductio and propose the following moral: Saying that God can’t do something may sound a bit strange at first, but the alternative is madness.

I wish I could say that this whole business about the possibility of contradictions in Heaven was rooted in my students’ piety alone—in their wish to safeguard the majesty of God. I have little doubt, however, that they’re willingness (even eagerness) to credit the Divine with a tertium which is obviously non datur is rooted at least in part in their wish to avoid the hard edges of truly rigorous argument. If only the occasional A could also be not-A—if only they could have their propositional cake and eat it too—they wouldn’t have to think so hard!

But let’s not lay all the blame on the young people. Given the postmodern and other relativistic pseudo-philosophies by means of which our students’ minds are increasingly victimized, their attitude is hardly surprising. Contextualization can’t help but induce complacency in the face of contradiction.