ears ago I discovered (the hard way) that the Internet is not the friendliest place for anyone who wants to stand up for logic or defend the coherence of truth.
I've long been concerned about the erosion of rationality in postmodern culture. I've always known there are naive Christians who mindlessly parrot worldly values, and I've been concerned for years about the potential for mischief when spiritual-sounding Christian terminology gets blended with worldly irrationalism. But I had no clue how much and how far irrationalism had already infected the visible church when I posted this article on my website back in 1995.
The article is a defense of the principium contradictionis, or "the law of contradiction"which says truth is by definition non-contradictory: "A is not non-A." (Some people prefer to speak of it as "the law of non-contradiction." Whatever.)
The law of contradiction is one of three principles classical logicians universally regard as foundational to all human thought. The other two are the law of identity, which states that an object is the same as itself: "A is A." Then there's the law of the excluded middle, meaning that when two propositions directly negate one another, one must be true and the other false; there is no third alternative: "Either A or non-A, but not both A and non-A."
The codification of those three principles is usually attributed to Aristotle. Most philosophers have regarded them as self-evident. (There have been exceptions. Hegel hated classical logic.) But those rather simple principles are the basis of formal logic and rational thought. Without them, rational discourse is simply not possible. In fact, to deny any of those principles is (by definition) irrational.
Anyway, almost 15 years ago I wrote this little essay on the law of contradiction, and it unleashed the fury of several hordes of budding "postmodern Christians." They filled my in-box with protests, solemnly assuring me that human logic is just that: "human," and therefore ungodly. To acknowledge the incomprehensibility of God is to embrace the incoherence of truth, they (illogically) insisted. Illogic? Who cares? They proudly and steadfastly embraced several contradictions in their own worldview. Their theology (early Emergent nonsense) seemed deliberately muddled. Contradictions in one's doctrine are more to be desired than gold, they seemed to be saying. Their whole idea of "faith" was a Kierkegaardian leap into dark nothingness, where (apparently) any and all biblical propositions are fair game for quacks and amateurs to question or contradict, depending on their personal whims.
But the principium contradictionis they could not tolerate, because it contradicted ideas that were frankly more basic to their worldview than the plain statements of Scripture.
So one of these guyslet's call him Darylwas especially persistent. He e-mailed me again and again, and promised to supply me with "incontrovertible proof that the law of contradiction is false." The irony of his own boast escaped him, and it was clear from the start that his mouth was writing a check his mind could never cash. But he "stayed up half the night" noodling on the problem, then wrote me to say he had two propositions that debunked the principium contradictionis. Here's the salient part of his e-mail: