Is Christianity Illogical? (A Presuppositional Argument)
Is Christianity illogical? This is the same as asking whether Christianity violates the laws of logic, i.e. the rules that govern proper thought and the relationship between a conclusion and its premises.
What Are the Laws Of Logic?
The laws of logic are:
Identity: A = A ("It is what it is")
Noncontradiction: A ≠ not-A ("It is not what it isn't")
Excluded middle: A or not-A ("A statement is either true or false").
Rational inference: A=B, and B=C, so A=C (used to reason from the general to the specific, as in "all men are mortal; Bill is a man; therefore Bill is mortal).
What Are the Laws of Logic Like?
These laws govern all our thinking (you are assuming they are true right now, even as you read this post and to see if it "makes sense"). They exist, and they exist in your mind. In my mind too.
And yet I didn't invent them, and neither did you.
And the ones in my head aren't different from the ones in yours (the way my imagination of, say, a unicorn might be different from your imagination of one).
These laws are not made of matter (how could a law be made of matter? "Could you hand me a bucket of logic?")
They apply everywhere at all times.
There are no exceptions to them (a thing is never not itself!).
They never change (there was never a time when a statement could have been both true *and* false in the same way at the same time, and there never will be such a time).
And they are directly knowable. We discover them (not invent them), even without any interaction with the outside world. Even if all I knew was myself, I could determine that I was me, that I was not me, that "I am me" is either true or false (but not both), etc. etc. etc.).
So these laws of logic are real, but they are immaterial, universal, absolute, unchanging, and knowable.
And how important are the laws of logic? They are vital! Nothing that is self-contradictory or illogical can be true, and nothing that is true can be self-contradictory or illogical.
Does Christianity have any explanation for how such laws could exist?
Yes!
Logic and God
The laws of logic perfectly express God's own thinking. According to the Christian worldview, God is perfectly logical, never contradictory, and totally rational in all he says and does. This means that the Bible, which is God's word, exhibits the same qualities (sometimes alleged contradictions or discrepancies arise, and our belief in God's nature is what prompts us to discover these and explain them; if we didn't believe in logic, we would have no reason to do so. But we do believe in logic, because we believe in God, so we do so. And when we do, we discover there are no true contradictions in Scripture).
Furthermore, the laws of logic themselves are perfectly grounded in God's nature.
They are immaterial, and God is immaterial.
They are universal, and God is universal.
They are absolute, and God is absolute.
They are unchanging, and God never changes.
They are knowable, and God is knowable.
The laws of logic are exactly what you would expect to discover in a world created by the God of the Bible.
In other words, if Christianity were true (and it is), then we would expect to find the laws of logic as characteristic of God, the world, and our own thinking (of course sometimes we fail to be perfectly logical, which is why it's good to have friends to help!).
However, if Christianity were *not* logical, then it would be necessarily false. But this would mean that God's nature and character would *not* be the basis for logic. This would mean that there would have to be some *other* basis for logic (I'll save you the trouble; no other worldview—and certainly not atheism!—provides a necessary basis with all the above attributes).
So then, the laws of logic would just be something we prefer, with no basis in reality. They would be unreal. Untrue. And ultimately unimportant. And if you said "That's false!" I could just say, "So it's true," and that would be valid. Because logic would have no basis in a world without God.
Logic Presupposes Christianity
So then, to ask the question, "Is Christianity illogical" gives the answer away. It assumes that "logic" is a meaningful concept, which means logic has all the attributes we've mentioned, which assumes a universe in which such laws could exist, which assumes the God of Christianity (who, again, has all those attributes needed to ground logic) exists, which assumes the truth of Christianity.
And whatever is true must also be logical. So the question, which (tacitly) assumes the truth of Christianity, also tacitly assumes that Christianity is logical.
To ask "Is Christianity illogical" is to answer it: No.