The law of contradiction means that two antithetical propositions cannot both be true at the same time and in the same sense. X cannot be non-X. A thing cannot be and not be simultaneously. And nothing that is true can be self-contradictory or inconsistent with any other truth.
All logic depends on this simple principle. Rational thought and meaningful discourse demand it. To deny it is to deny all truth in one fell swoop.
Until a little more than a hundred years ago, the law of contradiction was almost universally accepted by philosophers as a self-evident truth. Francis Schaeffer attributed the decline of 20th-century society to the demise of the law of contradiction. He suggested that when philosophy abandons this principle it sinks beneath "the line of despair" and ultimately makes suicide the only viable course of action.
Scripture very clearly affirms the law of contradiction. First John 2:21, for example, is explicit: "No lie is of the truth." Many other passages, such as 2 Timothy 2:13, ("[God] cannot deny himself") either assume or reiterate the law of contradiction.
Lots of well-meaning Christians, however, seem to operate with the misconception that biblical revelation is somehow exempt from the law of contradiction. They suggest that God's truth can contravene logic if God is so pleased. They often point to the doctrine of the Trinity or pit divine sovereignty against human responsibility as evidence that revealed truth is sometimes contradictory.
But Titus 1:2 tells us that "God . . . cannot lie." Therefore even God's Word must be in harmony with the law of contradiction. One clear, unresolvable contradiction would be enough to destroy the trustworthiness of the whole. That's why the enemies of truth are so eager to try to prove that God's Word contradicts itself.
Certainly we who love truth ought to jealously guard against any suggestion that God's revelation is internally inconsistent. But more than that, we need to defend the law of contradiction itself, because this is a biblical principle, and it lies at the root of all truth.
I'm troubled when terms like paradox and antinomy are bandied about by Christians without sufficient explanation. Neo-orthodoxy built a whole theology of contradictory ideas by labeling every incongruity a "paradox." But be warned: when the neo-orthodox use the term paradox they are actually speaking of real contradictions. Their whole system is designed to accommodate those contradictions. Thus they have baptized irrationality and labeled it Christian. But it is not true Christianity.
I'm frankly not even comfortable with the common use of the term antinomy to describe the tension between divine sovereignty and human responsibility. According to the Oxford English Dictionary, antinomy is "a contradiction between two equally binding laws; a conflict of authority; and a contradiction between conclusions which seem equally logical." I don't believe a true contradiction exists between divine sovereignty and human responsibility. (If you believe these doctrines plainly contradict each other, you'll have to demonstrate where the contradiction lies. I don't believe any such "contradiction"— real or apparent—exists. But I'll save that discussion for another article.)
What about Jesus' "paradoxical" statements—"the first shall be last," "you must lose your life in order to save it," and so on? These are not contradictions, but plays on words. Jesus was not asserting contradictory propositions, but merely using oxymoronic language to stress the point He was making.
The Trinity is certainly difficult (no doubt impossible) for the human mind to fathom, but self-contradictory it is not. We do not believe that God is three in the same sense that He is one. A reading of the church councils' teachings on this doctrine will reveal that historic orthodoxy has carefully avoided the language of contradiction. The church Fathers knew very well that to concede the critics' charge that this truth is self-contradictory would have been tantamount to saying that Christianity itself is false.
What they knew—and modern Christians often miss—is that whenever our language shifts into the vocabulary of antinomy and contradiction, the words themselves no longer communicate. If we overthrow the law of contradiction, literally anything might be true. Black might mean white and hot might mean cold and everything would mean nothing. This is exactly where most modern men and women now live—in the abyss of existentialism, where Joe and Sally might hold world-views that flatly contradict one another—yet both earnestly deny that if one system is right the other must be wrong. This type of thinking seems merely affable and benign, yet it destroys the very concept of truth.
Many discard the law of contradiction precisely so they can declare truth falsehood and make righteousness evil. Therefore the notion that truth might be inconsistent with itself is one of the most popular but pernicious misconceptions held by the unbelieving men and women of our age. It is a concept hostile to truth and fraught with deadly danger. That's why it is absolutely crucial that we who believe every word of God is true must oppose irrationality with every fibre of our being.
Consider this, for example: if antithetical propositions can simultaneously be true, then who are we to say that those who deny the deity of Christ are actually wrong? If contradictory propositions can be true, then Arianism might actually be just as true as Trinitarianism. What's the point in defending any truth in a system like that? See the problem?

Phil Johnson

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