Genetic and Ad Hominem Fallacies

Genetic and Ad Hominem Fallacies October 10, 2014

Genetic and Ad Hominem FallaciesIn 2012, the Heartland Institute (an American conservative think tank) put up a series of billboards featuring Ted Kaczynski (the Unabomber), Charles Manson (a cult leader), and Fidel Castro (a dictator). The text was the same for each: “I still believe in Global Warming. Do you?”

These are examples of the genetic fallacy. We’re asked, “How plausible can the claim of global warming be if these nutjobs accept it?” A genetic fallacy ignores any actual evidence or argument and looks instead at the origin (think genesis) of the argument. It’s a fallacy because it offers no relevant argument.

More examples

Another example would be, “You’re a vegetarian? Don’t you know that Hitler was a vegetarian?”

But consider this: “You can’t tell me that those new phosphorescent zucchinis are safe! Don’t you know that the research that supports that claim was funded exclusively by MegaCorp, the company that patented that vegetable?”

This makes more than a simple origins claim (X comes from/is supported by Y) and is more compelling. To make this a classic genetic fallacy, we’d need to strip it down like this: “Don’t tell me that phosphorescent zucchinis are safe! MegaCorp says they’re safe.” Maybe the research funded by MegaCorp was actually good science.

Genetic fallacies in Christianity?

Now consider these claims: “Christianity was influenced by myths of dying-and-rising saviors; therefore, the resurrection of Jesus must also be a myth.” Or, “The Noah flood story came from a society influenced by neighboring flood stories like that of Gilgamesh; therefore, the Noah flood story is a myth.”

These are (1) genetic, since they make conclusions based on origins, (2) unsubstantiated, since these claims will need lots of supporting evidence, and (3) fallacies. I would argue that these aren’t genetic fallacies, however. They fail in my mind because the unequivocal conclusion (“… must also be a myth”) can’t be drawn from evidence that simply points in that direction.

The fallacy vanishes when we make a conclusion that could follow from the evidence: “Christianity was influenced by myths of dying-and-rising saviors; therefore, we must consider that the resurrection of Jesus may also be a myth.” We still have work to do to establish that Christianity was influenced as claimed, but the fallacy is gone.

Related fallacies

The genetic fallacy is the term for any argument that points solely to origin as its evidence, but there are many subsets of the genetic fallacy based on the specific origin.

  • Ad hominem: attacking the person rather than the argument. “Senator Jones wants to raise taxes, but he beats his dog; therefore, raising taxes is a bad idea.”
  • Tu quoque: saying, in effect, “Oh yeah? Well you do, too!” This argument tries to respond to a problem by claiming that the other person suffers from it also.
  • Argument from authority fallacy: using someone as a relevant source when that person is not an authority in the field at hand or is biased.
  • Credential fallacy: rejecting an authority because that person doesn’t have the right degrees.
  • Ad feminam: rejecting an authority because that person is a woman.

And so on.

Avoid making thoughtless charges of these fallacies. Not every attack on a person is an ad hominem fallacy. “Just ignore that fire alarm; that’s nutty Mrs. Smith” may be a fallacy, but “Ignore that fire alarm; that’s Mrs. Smith, and she’s phoned in a false alarm every week for three years” isn’t. (It may not be the safest response for the fire department, but it’s not a logical fallacy.)

And as seen above, not every genetic (origins) argument is a fallacy.

The human race can’t quit stupid cold turkey.
— commenter Greg G.

(This is an update of a post that originally appeared 5/12/12.)

Photo credit: Simon Varwell


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