How to Argue Logically

I have been reading about different philosophers and their works and contributions. I found this article below quite interesting and so decided to share ot with you all. This piece of work is contributed by Richard H Popkin. (December 27, 1923—April 14, 2005) was an academic philosopher who specialized in the history of enlightenment philosophy and early modern anti-dogmatism. His 1960 work The History of Scepticism from Erasmus to Descartes ^[1]Pyrrhonian Scepticism of Sextus Empiricus. Popkin also was an internationally acclaimed scholar on Jewish and Christian millenarianism and messianism. introduced previously unrecognised influence on Western thought in the seventeenth century, the

How to Argue Logically

We like to think that we speak logically all the time, but we are aware that we sometimes use illogical means to persuade others of our point of view. In the heat of an impassioned argument, or when we are afraid our disputant has a stronger case, or when we don't quite have all the facts we'd like to have, we are prone to engage in faulty processes of reasoning, using arguments we hope will appear sound.

Such defective arguments are called fallacies by philosophers who, starting with Aristotle, have catalogued and classified these fallacious arguments. There are now over 125 separate fallacies, most with their own impressive-sounding names, many of them in Latin.

Some arguments have easily recognizable defects. For instance, in the argument ad hominem, a person's views are criticized because of a logically irrelevant personal defect: "You can't take Smith's advice on the stock market; he's a known philanderer." In the genetic fallacy, something is mistakenly reduced to its origins: "We know that emotions are nothing more than physiology; after all, medical research has shown emotions involve the secretion of hormones." Another illogical argument is named for the erroneous thinking a wagering person may fall prey to, the gambler's fallacy (also called the Monte Carlo fallacy): "I'm betting on heads; it's got to come up since we've just had nine straight tails."

Some fallacies may not be recognized as erroneous reasoning because they are such commonly used forms of argument. For instance, if we say, "I'm sure my cold is due to the weather; I started sneezing right after it went from 60 degrees to 31 degrees in three hours," we are committing the fallacy with the Latin name of post hoc ergo propter hoc ("after this, therefore because of this"). Many a political argument exemplifies the fallacy of arguing in a circle; for instance: "Only wealthy men are capable of leading the country; after all, leadership can be learned only if you have had money to exercise power." Many prejudicial or stereotypical arguments commit the fallacy of division, or of applying to the part what may be true of the whole: "North Dakota has wide-open spaces; since Jack's farm is there, it must be quite large." The converse of this is the fallacy of composition, where properties of the parts are erroneously attributed to the whole: "Every apple on this tree is rotten; therefore, the tree itself is hopelessly diseased."

It may be a surprise to realize that some widely accepted forms of argument are just as fallacious as the most logically defective reasoning. When we appeal to the beliefs or behavior of the majority to prove the truth of something, we are committing the fallacy of consensus gentium: "Imbibing alcohol cannot be bad for people, since all cultures studied have used alcohol." Or consider the person who argues that "Tragedy is the highest form of literature; after all, didn't Aristotle consider it such?" This is a form of the fallacy of arguing from authority. There is also the fallacy of ignoratio elenchus, which has nothing to do with ignorance; its name means that the point made is irrelevant to the issue at hand, as in the untenable view of a lawyer who says, "Ladies and gentlemen of the jury, you cannot convict my client of manslaughter while driving under the influence; after all, advertisements for alcohol exist everywhere in our culture."

Fallacy

{fal'-uh-see}

In logic, a fallacy is a form of reasoning that is illogical or that violates the rules of valid argumentation. A formal fallacy makes strict violations of the rules of logic. An informal fallacy does not violate the rules of logic, but it violates the rules of valid reasoning or arrives at unsound conclusions, because of unsound reasoning.

A common formal fallacy involves affirming the consequent or denying the antecedent in hypothetical reasoning. That is, if A, then B, affirming B as the proof of A, or denying A as the basis for denying B. In either case, it does not follow that the affirmation or the denial proves what is claimed. Thus, if all Americans are bald (A), then all Americans require no hairdressers (B)--the affirmation of B, that is, saying it is true, does not prove A; neither does the denial of A prove the denial of B.

Two other kinds of formal fallacies that are important are the argument from the undistributed middle and the conversion of a universal positive proposition. In the first, it is argued that "all A is B" and "all C is B"; therefore, "all A is C." If "Americans" is substituted for "A", "human beings" for "B", and "Hungarians" for "C", it is easily seen that the argument is fallacious. In the other case, it is argued that if "all A is B," then "all B is A"; this is obviously fallacious if the same substitutions are made.

Because informal fallacies occur much more frequently in ordinary discussions, in political speeches, and in advertising, they are, in some ways, more important. Some of these fallacies are a result of the ambiguity of the terms used; people often slip unconsciously from one meaning of a term to another. Other major informal fallacies are the ignoratio elenchi, that is, arguing for something different from the question asked; and the tu quoque argument, in which an unsound argument is justified by claiming the unsoundness of another. These soon degenerate into the argument ad hominem, in which the argument of an opponent is countered by pointing to his or her personal faults rather than by considering the substance of the argument; and the argument from authority, which appeals to famous or important people who agree with a particular point of view.

Richard H Popkin