I’m in agreement with Justin that, on my understanding of what rationality is, neither concept could apply. I can give some fundamental reasons why this is so if you like.
Why cannot God be rational?
Rationality is the commitment to reason as one’s only means of acquiring and validating knowledge, and as his only guide to chosen action. By contrast, irrationality is the reliance on something other than reason (e.g., emotions, astrology, palm-reading, tea leaves, faith in invisible magic beings, etc.) to acquire and/or validate knowledge and guide his choices and actions. In general, rationality is compliance with reason, and irrationality is non-compliance with reason. If you look up ‘rational’ in the dictionary, even here you will find a close connection with reason.
Now reason is the faculty which identifies and integrates perceptual input. This faculty is made possible by the ability to form concepts from perceptual input (and higher concepts from the initial concepts formed on the basis of perceptual input).
It should not be difficult to recognize from this why man needs rationality. He needs rationality because he needs reason. And he needs reason because he needs knowledge in order to live, and reason is how he gets that knowledge. If he does not get the knowledge he needs to live, man will die. Like any living organism, man faces a fundamental alternative: life or death. So if man wants to live, he has no choice but to employ his faculty of reason.
When it comes to the Christian god, however, we have a much different story. The concept of rationality would not apply since the concept of reason could not apply. Take for example the claim that the Christian god is omniscient. It is all-knowing, possessing all knowledge. There’s nothing this god doesn’t know, so we are told. Would it make sense to say such a being is “rational”? Well, again, if rationality is a commitment to reason as one’s only means of acquiring and validating knowledge and his only guide to chosen actions, then clearly it wouldn’t make sense. An omniscient being would have no use for a means of acquiring and validating knowledge, since it is said to already possess all knowledge. There would be no knowledge for it to acquire or validate. Essentially, such a being could not learn. So there’d be no need for it to be committed to reason as its only means of acquiring and validating knowledge, for it already knows everything. To call such a being “rational” in this case would be to say it is committed to something it couldn’t possibly need. So it would be a stolen concept at this point.
Also, since the Christian god is said to be non-physical and bodiless, it wouldn’t have any sense organs. It wouldn’t have eyes, ears, a tongue, a nose, skin. It wouldn’t have nerve cells, a spine (yes, the Christian god is spineless), or a brain (yes, it’s brainless, too). Because it lacks sense organs, a nervous system and a brain, it would not have awareness via senses. Consequently, it would not have perceptual input from external stimuli, such as when we see an apple, a grove of trees, a baby, a city skyline. Consequently, it would have no perceptual input to identify and integrate. This is yet another reason why the Christian god would have no use for reason, and consequently no need to be committed to reason (i.e., rationality). So again, the theist has another stolen concept on his hands when he claims that his god is “rational.”
Another point is that, because the Christian god is said to be omniscient, it would not possess its knowledge in the form of concepts. I have already given my argument for this conclusion here. The point here is that, since reason is a conceptual process, a being which would not have its knowledge in the form of concepts would have no use for it. So to call such a being “rational” is, again, to say that it is committed to something it would have no use for and could not need. So here we have a third count of the fallacy of the stolen concept.
A final point is that, because the Christian god is said to be eternal, indestructible, omnipotent, etc., it would have no need or use for a guide for its choices and actions. Unlike man, who faces a fundamental alternative and can die if he acts on bad choices, the Christian god could do anything, and no harm would come to it. In fact, it could sit idle for all eternity, performing utterly no actions whatsoever, and it would still continue on as what it is just fine.
So these are some reasons why I would say that neither the concept ‘rational’ nor ‘irrational’ would apply to the Christian god. It would be, like a rock on a hillside or an asteroid in the cold of space, wholly arational, and for reasons which are not dissimilar: like the Christian god, rocks and asteroids have neither need nor use for a faculty for acquiring and validating knowledge, nor do they have either need or use for a guide to action. So consequently, they would have no need or use for committing themselves to such a faculty or guide.
by Dawson Bethrick