A friend recently recommended to me a video promoting something called Family Integrated Church. In the midst of a nicely-done presentation, the video contained some logical gaffes that thoroughly soured me on the case being made. Among these was a claim that teaching children in classes separated by age is morally wrong because the practice has atheistic roots:

“You have John Dewey,…he was an atheist, he was a hater of the Bible….He spent his life building this age-segregated school system. The church went and adopted that age-segregated system.”

This argument attempts to discredit the use of age-segregated teaching not by considering the practice itself, but by claiming that the practice necessarily originated with an atheist. In other words, the reasoning goes this way:  atheists are always wrong, so this idea is wrong.

This is a good example of the genetic fallacy, a fallacy in which the mere origin of an idea or practice is presented as proof for or against its validity. The genetic fallacy, like the ad hominem, is formally categorized as a fallacy of irrelevance. It promotes a conclusion that may or may not be valid, because it ignores the very point that it seeks to prove.

There are a number of ways in which we may indulge in the genetic fallacy. In some instances, one simply claims that an argument has a source that is somehow undesirable.

Another variant is the psychogenetic fallacy, in which it is assumed that by accounting for the psychological origin of someone’s argument, we can dismiss that argument altogether. A.J. Hoover, in his helpful little book “Don’t You Believe It,” provides this example of pyschogenetic fallacy:

[Sigmund Freud] said that God was nothing more than a psychological projection. He argued that God doesn’t exist, but that the belief in God is widespread in all human cultures because man “projects” his fears onto the universe as a whole. As a child grows up he learns to lean on his (real) earthly father for psychological support in the early, fragile years. When he matures, he finds out that he must give up this parental crutch and face the world alone. Such isolation is too much for most people; they create an imaginary cosmic father, God, and then proceed to fear and propitiate him and trust him for lifelong protection. Thus did Freud explain religion as a universal neurosis….

But the psychological reason why I believe in God in no way renders it less probable that God exists, nor, conversely, does it prove that God exists. It proves nothing either way.

We can also commit the genetic fallacy when we claim that the nature of a thing is irrevocably tied to its origin. So, for example, we might note the (apocryphal) claim that the quaint custom of a bridegroom carrying his bride over the threshold of their new home has its origin in the ancient custom of men finding wives by kidnapping them and carrying them off against their will. On this basis, it is argued, the practice should be avoided, because it implicitly condones abduction and rape.

Nicolas Poussin - Abduction of the Sabines

Even assuming the accuracy of the purported origin, the custom holds no such significance today, and it makes no sense to assert that the meaning of a custom can never change.

There is a further variant of the genetic fallacy called the etymological fallacy. When we assert that the meaning of a word at one point in time (usually, but not always, the present) is necessarily directly linked to its original meaning, we commit the etymological fallacy. A common way of expressing this error is by claiming that the true or “root” meaning of a word will always be found in its etymology. In fact, because language can change in strange ways, this is not necessarily true.

This fallacy is tricky, because there are instances where etymology can elucidate meaning. I recently learned that the work “feckless” (meaning lacking in purpose; ineffective, or powerless) has its origins in the Middle English word, “fek,” which meant value or efficacy. In this case, there is some value in seeing that the meaning “lacking in value” arises from the word’s archaic root. Still, we could have learned the meaning by looking at the word used in context; the etymology is just gravy.

In contrast to “feckless,” the word “nice” has been cut loose from its etymology, as it comes into modern English from Latin (nescius = ignorant) through a Middle English word that meant foolish. Chaucer’s “The Reeve’s Tale” begins with the line, “Whan folk hadde laughen at this nyce cas,” in which “nyce” means “foolish,” with reference to the Miller’s Tale. Modern meanings of “nice” bear little resemblance to the word’s roots, and to insist otherwise would be…ignorant.

The genetic fallacy is a handy tool if you are making an argument to your own partisans. Among Christians, for example, if you’re trying to show that an idea is bad, many of us will be swayed by a claim that the idea has pagan (or atheistic) origins. This was the approach used in my opening example. If we wish to argue in favor of a point of view, citing a respected authority who held to that view will often elicit a groundswell of support (among the Reformed, using John Calvin’s name in combination with this technique is often a slam-dunk). ^{[ 1 ]} In any group, there will almost always be people willing to believe an argument because some notable person believes it. Of course, arguments thus made are not logically valid, a fact that ought to nag our consciences when we employ the genetic fallacy.

I suppose that if a disreputable person makes an argument, that argument might deserve careful scrutiny before we accept it. This, strictly speaking, is not the genetic fallacy, because one is not saying that the argument is necessarily invalid because of its source. By the same token, we may feel that an argument made by a respected person is more worthy of consideration – but if we subsequently adopt the argument solely on the basis of someone’s endorsement, we slip into fallacious reasoning.

Like the ad hominem, the genetic fallacy often takes advantage of our prejudices for (or against) certain people or ideas. Like the pickpocket’s trick of bumping into us while he relieves us of our wallet, the genetic fallacy seeks to focus our attention on something irrelevant while distracting us from something important. Since we tend to present arguments informally, rather than rigorously, we are even less likely to notice that the rules of logic have been violated when a genetic fallacy is being used.