We have already taken up in the previous three columns the nine most common kinds of material fallacies, so we will now proceed to the second broad category of logical fallacies—
the fallacies of relevance, which are arguments that seek to persuade people to accept evidently nonlogical propositions.
In this form of fallacy, the premises and evidence offered are actually irrelevant to the conclusion, but they are couched in language that makes them somehow psychologically or emotionally persuasive. People often have very strong opinions about the issues in fallacies of this kind, so they seldom notice when their attention has been diverted from the real issue.
Indeed, on the strength of one person’s persuasive powers alone, fallacies of relevance are often demonstrably false and can hook in only the unwary, the predisposed, and the gullible. But with the growing sophistication of their purveyors in using the modern mass media, particularly television and radio, this form of illogic often acquires enough power to break the rational defenses of even the intellectually sophisticated and astute.
The 13 most common kinds of fallacies of relevance, identified and catalogued as early as 2,600 years ago during Aristotle’s time, are the following: fallacies of irrelevance (
ignoratio elenchi), personal ridicule (
ad hominem), appeal to the people (
ad populum), appeal to authority (
ad verecundiam), appeal to ignorance (
ad ignorantiam), appeal to pity (
ad misericordiam), appeal to force (
ad baculum), appeal to money (
ad crumenam), emotive language,
tu quoque, genetic error, anthropomorphism, and
non sequitur.
We will now dissect a few specimens and show why their kind of reasoning can’t stand rigorous logical scrutiny.
Fallacies of irrelevance. Better known as
ignoratio elenchi (which means “irrelevant conclusion”), this broad category covers practically all of the fallacies of relevance. They try to establish the truth of a proposition with arguments that support an entirely different conclusion. Example: “I’ve been accused of fathering my secretary’s child, but she actually signed an affidavit that the child is actually the fruit of artificial insemination. Therefore, I couldn’t have possibly fathered that child.”
That the woman had declared under oath that her child was conceived through artificial insemination would seem to clear the man of wrongdoing. However, it really isn’t conclusive proof that he didn’t father that child. What if the woman, out of love or terror or poverty or charity, is simply trying to protect the man’s reputation? The affidavit—that all-purpose device of law to support truth and falsehood alike—doesn’t really settle the biological and parental aspect of the premises. The only thing it proves is that the woman signed it. (Thankfully, modern science has developed the DNA test to scientifically debunk fallacies of this type.)
Personal ridicule (ad hominem). When someone ridicules another rather than directly addresses the premises of his or her argument, one commits the fallacy of personal ridicule. Two examples: “You wouldn’t believe someone of such low social stature, would you?” “She may be right about the country’s economic situation, but don’t you remember that she was outrageously wrong twice during the past 10 years?”
Easily the most popular variety of this fallacy is the so-called “straw man,” the tactic of misrepresenting someone’s argument to make it easier to refute. The trick is to distort an aspect of someone’s premises to make it less credible, attack the now distorted position, and then claim that the whole argument has been refuted.
Take the following conversation as an example:
Niece to uncle: “Uncle, I’d like to take up mass communications instead of nursing. I think I’m not really cut out for nursing.”
Uncle to niece: “You unthinking moron! Mass communications graduates today are dime a dozen. Nursing is the most in-demand job abroad these days!”)
We will continue this discussion next week.
(Next:
Watching out against the fallacies of relevance–2) August 17, 2017
This essay, 1052nd of a series, appeared in the weekly column “English Plain and Simple” by Jose A. Carillo in the Education Section of The Manila Times
, August 10, 2017 issue (print edition only), © 2017 by the Manila Times Publishing Corp. All rights reserved.
