Another Favorite Fallacy: Judging An Argument By Its Source

In a previous essay, I identified the ad lapidem fallacy as the one most commonly used in social media “debates” (I use that term very loosely). This is the tactic of responding to an argument not by addressing its substance, but by mocking it, scoffing at it, or otherwise denigrating it so that observers will think the position false because it is patently ridiculous. The ad lapidem fallacy is the evil twin of the legitimate reductio ad absurdum strategy, which teases out the logic of an argument to show that it reaches an unacceptable conclusion, and is therefore false. As with all fallacies, the ad lapidem fallacy works precisely because it resembles its valid counterpart just enough to be mistaken for it at a quick glance.

There is another fallacy, though, which may be used almost as frequently: the genetic fallacy.

We commit the genetic fallacy when we evaluate an argument or an idea based not on its merits, but on its root cause. That is, we accept or reject an idea based on whether we find its source of origin agreeable to us. Rather than examining the structure of the logic or the truthfulness of the premises, we simply ask, “Who said that?” And if we find that the argument or an idea has an odious lineage, we dismiss it as we would a telemarketer: with confident contempt.

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Both the ad lapidem fallacy and the genetic fallacy appeal to a different drive in us. The ad lapidem fallacy scratches that itch we have to mock our opponents, to discredit their arguments, and to have ourselves appear clever and witty. The genetic fallacy reinforces our belief that our opponents are fundamentally corrupt, that nothing will come forth from them but error and vice, that every word that comes out of their mouths is a lie, including “and” and “the” (to quote Mary McCarthy). It’s a form of prejudgment, or prejudice. And, typically, prejudice is not a desirable trait.

Politics provides us prime examples of people rejecting ideas because of whom they’re associated with. During the 2012 presidential election campaign, one late-night talk show sent out TV crews to ask people their opinions on the candidates’ views—but they swapped their positions. So, folks on the street were told that Mitt Romney wanted to require people to buy health insurance (which was actually a key component of the Obamacare law which had already been passed two years prior), to which Obama supporters had responses to the effect of, “Of course, that’s just like those dictatorial Republicans, trying to control people’s lives. That’s exactly why I don’t support him!”

This was further demonstrated in a 2015 HuffPost/YouGov poll showed significant variations in public support for universal health care, Social Security protections, and the Iran nuclear deal depending on who it was the respondents were told supported the measure. Support for universal health care dipped significantly when respondents were told Donald Trump favored it versus when they were told that Barack Obama had praised it, while the Iran deal gained steam when Trump was supposed to support it compared to when John Kerry was attached to it.

The current occupant of the White House has turned much of our political reporting into one continuous exercise of the genetic fallacy. President Donald Trump is, to put it mildly, a polarizing figure. Some people love him and applaud his every move. Some people hate him with a visceral passion usually reserved for serial killers and the rival team’s quarterback. These people echo the sentiment of that great philosopher, Groucho Marx, who once sang, “Whatever it is, I’m against it.” Go back in the Twitter feeds of the likes of Evan McMullin and Jennifer Rubin and see how their positions have shifted in response to Trump’s support for them.

As damaging as this bad mental habit is in our political life, it is even more harmful in the life of faith. When people form a negative view of the Church or the Catholic faith, for whatever reason, they become closed off to its saving message, its salutary suggestions for how to live a good and fulfilling life, its warnings about the dangerous paths our society has set down.

Thus when the chickens of the Sexual Revolution come home to roost, from the degradation of the family to our current moment of revelation about widespread sexual predation by powerful men in entertainment and politics, and one points out that such consequences were predicted by Pope Paul VI in Humanae Vitae as a natural consequence of the separation of sexuality from its final cause of procreation, such knowledge is not met with a recognition of the Church’s wisdom and insight to the human condition, but a scornful look and an irrelevant comment about the imperfections of certain priests.

Or consider that when assisted suicide first came to the ballot in Oregon, the pro-euthanasia crowd ran ads simply saying, “The Catholic Church is funding the battle against this bill. You don’t want the Catholic Church telling you what to do, do you?” Subtly summoning the spirit of anti-Catholicism that lies deep at America’s heart (as Arthur Schlesinger noted), the pro-death crowd played on a prejudice and said that if Catholics wanted to preserve life, it must be a bad thing.

The genetic fallacy is the logical equivalent of a cliché, in that, as George Orwell said, it does our thinking for us, coming to us “like prefabricated hen-houses.” We must do the hard work of considering each argument and claim on its own. Only then can we be open to the truth, and it is the truth that sets us free (John 8:32).


  • Nicholas Senz

    Nicholas Senz is Director of Faith Formation at St. Vincent de Paul Catholic Church in Arlington, Texas and a Master Catechist. A native of Verboort, Oregon, Nicholas holds master’s degrees in philosophy and theology from the Dominican School of Philosophy and Theology in Berkeley, CA. He is on Twitter @nicksenz and his own blog, NicholasSenz.

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