The size of the sample is too small to support the conclusion. “[This] type of argument [goes] under varied terms for the fallacy like over-generalization, glittering generality, accident, converse accident, or secundum quid (neglect of qualifications). Typically, however, two types of fallacies are emphasized. One is an inductive fallacy that occurs in statistical reasoning from a selected sample to a wider population. The other has to do with overlooking qualifications to a defeasible generalization.” (Douglas N. Walton, Argumentation Methods for Artificial Intelligence in Law, p. 39) By contrast, see “Slothful Induction and Ad Hoc Escapism“.
- “After only one year the alternator went out in Mr. O’Grady’s new Chevrolet. Mrs. Dodson’s Oldsmobile developed a transmission problem after six months. The obvious conclusion is that cars made by General Motors are just a pile of junk these days.” (Hurley, Logic, 1991: p. 142)
- “Iraq boasts quite a long history of intermarriage and intercommunal cooperation. But a few years of this hateful dialectic soon succeeded in creating an atmosphere of misery, distrust, hostility, and sect-based politics. Once again, religion had poisoned everything.” (Hitchens, god is not Great: p. 27. Emphasis in original.)
- “[Y]our opponent might argue that her client’s future lost profits are $2 million, based on profits from one prior year. But if that year’s profits were unusually high, her generalization is based on data that is deficient in both quantity (only one instance) and quality (an atypical year).” (Waicukauski, Sandler, and Epps, The Winning Argument: p. 50)
- “Madame Luna predicted in 1980 the fall of Russian communism; so, Madame Luna is a reputable psychic. The argument can be revised as: One observed prediction of Madame Luna has come true; so, all of Madame Luna’s predictions must come true.” (Holowchack, Critical Reasoning and Philosophy, p. 80.)
- “Here is a gentleman of the medical type, but with the air of a military man. Clearly an army doctor, then. He has just come from the tropics, for his face is dark, and that is not the natural tint of his skin, for his wrists are fair. He has undergone hardship and sickness, as his haggard face says clearly. His left arm has been injured. He holds it in a still and unnatural manner. Where in the tropics could an English army doctor have seen much hardship and gotten his arm wounded? Clearly in Afghanistan.” (Sherlock Holmes in Sir Arthur Conan Doyle’s A Study in Scarlet.)
- “We arrived at the park gate at 7:25 P.M., at which time the cashier gleefully took our admission money. Upon entering the zoo and walking across the bridge, we heard the loudspeaker state that the zoo building were closing at 8:00 P.M. and that the zoo itself would close at 8:30 P.M. We went to the ticket counter and asked if we could get a pass for the following day. The answer was “no.” It is easy to see that Calgary is anything but friendly, but, rather, out to rake off tourists for all they can get.” (Johnson & Blair, Logical Self-Defense, p. 70.)
“[W]e may expose a fallacy in generalization by proving: 1) That the relative size of the unobserved part of the class is so large as to discredit the generalization. 2) That the members observed are not fair examples of the class. 3) That there are exceptions to the general rule or statement. 4) That it is highly improbably that such a general rule or satement is true.” (Foster, Argumentation and Debating, 1908, p. 146.) Note: in some cases, a formal proof would require a mathematical calculation. This is the subject of probability theory. More often,
common sense should suffice.
Hasty Generalization versus Secundum Quid
“Traditionally, [secundum quid] has been the term used for all Hasty Generalizations, but modern treatments have drawn the distinction between the hasty inductions of the last section and the failure to accomodate relevant exceptions. It is the latter that interests us here. Secundum quid means ‘in a certain respect’
and refers to qualification that may be attached to a generalization. What is the case in a certain respect may not hold generally. Sometimes a close association to an issue or perspective may blind us to reasonable exceptions to a general rule.” (Tindale, Fallacies and Argument Appraisal, p. 154.)
Essential versus Accidental Properties
The source of this fallacy’s persuasive power is its resemblance to valid arguments in which individual cases do fall under a general rule. The point to remember is that a generalization is designed to apply only to individual cases that properly fall under it. It is not designed to apply to special cases. It is certainly valid to argueEngel, Fallacies and Pitfalls of Language, p. 72.
that, since all men are mortal, Socrates is mortal. But it would be incorrect to argue: ‘Since horseback riding is healthful exercise, Mary Brown ought to do more of it because it will be good for her heart condition.’ What is good for someone in normal health does not apply where special health problems exist. The fallacy of sweeping
generalization is also referred to as the fallacy of accident, to emphasize the irregularity of particular cases to which generalizations do not apply.
One typical form of hasty conclusion occurs when the arguer uses anecdotal evidence. Evidence is anecdotal, as contrasted with systematic, when it takes the form or recounting an experience, often in story form, of one person or a few people… There is a difference between using a story to illustrate a thesis in a premise that has already been established and using a story to prove a point. We refer to the latter situation when we allude to the dangers of anecdotal evidence.Johnson & Blair, Logical Self-Defense, pp. 71-2.