Here is a collection of quotes concerning logical fallacies and the importance of logical thinking in life. The quotations are arranged in alphabetical order by author, from top to bottom. Click on the author's name in the Index below to go directly to that author's quote. If you know of a good quote that should be here, please send it to the Fallacy Files.

Bentham, Jeremy Carroll, Lewis Chan, Charlie Fischer, David Hackett
Geach, Peter Hillis, Burton Huxley, Thomas Henry Laplace, Marquis de
Peirce, Charles Sanders Russell, Bertrand

Without a popular assembly taking an effective part in the government and publishing its debates, and without free discussion through the medium of the press, there is no demand for fallacies. Fallacy is fraud; and fraud is useless when everything is done by force.

Source: Jeremy Bentham, Bentham's Handbook of Political Fallacies (Apollo Editions, 1971), p. 246.

Once master the machinery of Symbolic Logic, and you have a mental occupation always at hand, of absorbing interest, and one that will be of real use to you in any subject you may take up. It will give you clearness of thought—the ability to see your way through a puzzle—the habit of arranging your ideas in an orderly and get-at-able form—and, more valuable than all, the power to detect fallacies, and to tear to pieces the flimsy illogical arguments, which you will so continually encounter in books, in newspapers, in speeches, and even in sermons, and which so easily delude those who have never taken the trouble to master this fascinating Art.

Source: Lewis Carroll, Symbolic Logic, Part 1: Elementary (Fourth Edition) (Dover, 1958), p. xvii.

Charlie Chan: Hasty conclusion like toy balloon: easy blow up, easy pop

Source: Robert Ellis, Helen Logan & Edward T. Lowe Jr., Charlie Chan at the Race Track

Logic is not everything. But it is something—something which can be taught, something which can be learned, something which can help us in some degree to think more sensibly about the dangerous world in which we live.

Source: David Hackett Fischer, Historians' Fallacies: Toward a Logic of Historical Thought (Harper & Row, 1970), p. 306.

I have been in love with logic ever since my father started me on logic in my teens. Logic of itself cannot give anyone the answer to any questions of substance; but without logic we often do not know the import of what we know and often fall into fallacy and inconsistency.

Source: Peter Geach, quoted in Steve Pyke, Philosophers (1996).

There's a mighty big difference between good, sound reasons and reasons that sound good.

Source: Burton Hillis, cited in Laurence J. Peter, Peter's Quotations: Ideas for Our Time (1977), p. 425.

[S]cience is simply common sense at its best; that is, rigidly accurate in observation, and merciless to fallacy in logic.

Source: Thomas Henry Huxley, The Crayfish, Chapter 1

The mind has its illusions as the sense of sight; and in the same manner that the sense of feeling corrects the latter, reflection and calculation correct the former.

Source: Pierre Simon, Marquis de Laplace, A Philosophical Essay on Probabilities (Dover, 1952), p. 160.

Few persons care to study logic, because everybody conceives himself to be proficient enough in the art of reasoning already. But I observe that this satisfaction is limited to one's own ratiocination, and does not extend to that of other men.

Source: Charles Sanders Peirce, "The Fixation of Belief", Popular Science Monthly 12 (November 1877), pp. 1-15.

Logical errors are, I think, of greater practical importance than many people believe; they enable their perpetrators to hold the comfortable opinion on every subject in turn.

Source: Bertrand Russell, A History of Western Philosophy (Book-of-the-Month Club, 1995), p. 93.