• SumoMe

Every man needs to know how to persuade. Everything from buying a car, asking for a raise, advocating for a client, or convincing your significant other to go to the steakhouse over the French bistro involves the subtle art of persuasion. This eight-part segment is dedicated to teaching men how to argue by explaining the most common weaknesses in arguments, and hopefully how to avoid them.

19. Composition and Division

These two fallacies are often lumped together into one general fallacy, despite their differences. The composition fallacy is the fallacious inference that what is true of the parts is true of the whole. The division fallacy is the opposite: what is true of the whole is true of the parts. Sometimes, these conclusions are correct (the characteristics of a piece of apple pie are generally true for the whole pie), but we need to be careful that this general rule isn’t made into a universal rule.

For instance, take an example of a little kid who is thinking about the world (as they should). This kid says, “I can’t see an atom with my naked eye. My body is made of atoms. Therefore, my body can’t be seen with the naked eye.” He then walks into the kitchen and tries to sneak a cookie, where his mom tells him “No” because he will ruin his dinner. The kid then saunters back into his room and thinks, “Where did I go wrong?”

Well, unbeknownst to the kid, his/her thinking was flawed by the composition fallacy. The kid thought that the characteristics of his/her parts, when composed together, should then translate to the whole. This is flawed logic, despite how well it may present on paper. These types of fallacies are used in trying to disprove evolution, when creationists say, “The oldest living species is a few hundred or thousand years old, therefore life itself is only a few hundred or thousand years old.” Well, not so. Not only does this argument totally skip over the concept of extinction, it uses composition to say that the characteristics of various parts of existence therefore prove or compose the characteristics of the whole. In order to avoid this logical fallacy, make sure that the whole/part claim you espouse is based on other evidence than logic, and you should be safe from error.

20. No True Scotsman

This fallacy was “created” (in the loosest sense of the word) or coined by British philosopher Antony Flew. In his 1975 work, “Thinking About Thinking: Do I Sincerely Want to be Right?” he described a hypothetical situation:

Imagine Hamish McDonald, a Scotsman, sitting down with his Glasgow Morning Herald and seeing an article about how the “Brighton Sex Maniac Strikes Again.” Hamish is shocked and declares that “No Scotsman would do such a thing.” The next day he sits down to read his Glasgow Morning Herald again; and, this time, finds an article about an Aberdeen man whose brutal actions make the Brighton sex maniac seem almost gentlemanly. This fact shows that Hamish was wrong in his opinion but is he going to admit this? Not likely. This time he says, “No true Scotsman would do such a thing.”

This fallacy is not one of form, but of result. Just like Hamish, many people oftentimes qualify their statements by saying that anyone who acts in contradiction to their conclusion must be an impostor or a fraud.

For a simple example, consider the following conversation. “All Americans like hamburgers.” “I’m an American vegetarian, and I dislike hamburgers.” “Well, all true Americans like hamburgers.” The issue here is whether the class labeled as “Americans” is actually people who are American citizens, or another nebulous classification of “true Americans.”

This fallacy generally appears when someone’s argument fails and they are looking for a way to qualify their failed argument by changing the classification to a “true” or “genuine” something-or-other. “No son of mine votes democrat…no true son of mine votes democrat–you must be from Mars.”

21. Fallacy of Origin

This fallacy is one of my favorites, because it is so popular in a wide array of subjects. The origin fallacy (or genetic fallacy) represents those situations in which the validity of a conclusion is based in the conclusion’s age or origin, instead of on its face. This fallacy can either be an ad hominem attack (“You’re a carny, what do you know about astrophysics?”) or a sort of institutional justification (“We’ve believed this for years!”).

For example, many people who argue for the Mayan prediction of the end of the world claim that the Mayans had some sort of secret understanding of the universe. Simply because the prediction is old, does not mean it’s valid. Mayans also believed in human sacrifice would appease their gods, and bloodletting was the cure for most maladies.

The age of a belief should not bolster its credibility, but harm it. Any old belief is one that should be subject to critique and question–not the other way around. Science and human thought progresses and improves over time with life experience, and to cling to old beliefs because of some sort of inherent authority with age is not only prohibitive to progress, but makes for foolish and fallacious argument. Some old beliefs are still sound, but they should remain sound based on other modern evidence for them–not because their age dictates authority.

Additionally, the source of a statement should not dictate its correctness (or incorrectness). While evaluations of credibility are useful (probably shouldn’t take legal advice from an indigenous tribesman), the source of a statement should not entirely dictate the credibility of a statement. Even if the hypothetical carney is working the ring toss at the fair, he might also have a PhD in astrophysics and know full well what he’s talking about. To say, “You’re just a carney, what do you know?” and dismiss his statements on those grounds alone is to make a latent ad hominem attack and fail to address the point itself. Be careful that what you’re judging or arguing against (or for) are actions or statements, not character.

What examples of these logical fallacies have you experienced? Interested in more? Go read part 6.