The Fundamentals of Logic: What You Need to Know for Your Everyday Argument

Every argue with someone and know that their argument was not logical, but could not explain why? Here are five common logical fallacies. Next time you’re having an argument and you here one of these used…just pipe up “you just committed the fallacy of….”

The fallacies of Improper Conversion

1. The Fallacy of the Pharisee. Because holy men bow their heads in prayer, and say “Lord, Lord!” those who bow their heads in prayer and say “Lord, Lord!” are holy.

2. The Fallacy of the Patrioteer. Since all who love their country should be willing to publicly profess their loyalty, therefore, all willing to publicly to profess their loyalty love their country.

3. The Fallacy of the Bohemian. Artists live in an odd fashion; therefore, those who live in an odd fashion are artists.

The Fallacy of Equivocation

The attorney for the defendant wins the consideration of the jury when he argues that a person who “steps into the path of a car” has only himself to fault for his injuries. He then proceeds to show that the person injured “stepped directly into the path of the car” in the current case. The conclusion, “Plaintiff (the person injured) has only himself to fault,” seems to follow unavoidably. However, the plaintiffs attorney rebuts this argument by showing that in the first usage of the term “steps into the path of the car” it is assumed to mean walking in front of an oncoming automobile, say, 20 or 30 feet away. However, in this case plaintiff “stepped into the path of the car” only in the sense that he began to cross the street when the car was 300 feet away. Hence the fallacy.

The Fallacy of Composition

A man reasons that if he bought and traded for the top ten basketball players in the NBA, he would have the greatest team ever assembled. However, actual experience shows that even though he has more individual talent than any other team, when combined his players form a bad team. Just because he had many individual A players, does not mean he has an A team. This fallacy consists in arguing that something is true of a whole which can safely be said only of its parts taken separately.

The Fallacy of Division

The Democrat party is controlled by corrupt unions. Mr. Donald is a member of the Democrat party. Thus, corrupt unions control Mr. Donald. This of course is a fallacious argument, as what is true of the whole does not follow as true for the part. Of course, neither does it follow from what was stated above that corrupt unions do not control Mr. Donald.

• The Gambler’s Fallacy may also be considered an example of the fallacy of division. The gambler knows that the probability of getting heads four times in a row is rather small. Therefore, after three heads have turned up, he bets heads turning up on the fourth throw is now considerably less than ½. But this is foolish, for although the probability of getting heads four times in a row is 1/16, the probability of getting heads on the fourth throw, taken by itself, is still ½.

The Fallacy of Accent

“What a free country this is,” growled a man. He was promptly arrested by the dictator’s police, but managed to get himself off by pleading that all he said was, “This is a free country to live in!” Of course, the accent on the words was different in each case.

For more information on Logic, see A Handbook for Logic, Second Edition, Joseph Gerard Brennan, Harper & Row, Publishers.