# Consistency

Consistency means: "the property of holding together and retaining shape." This is the most commonly-used definition of the word. It describes something that is the same throughout. In classical deductive logic, a consistent theory is one that does not contain a contradiction. The lack of contradiction can be defined in either semantic or syntactic terms.

## Quotes

* The classic example of an axiomatic system is that of plane geometry formulated by Euclid... It forms the model of all rigorous mathematical schemes. The axioms are the initial assumptions... From them, logical deductions can proceed under stipulated rules of reasoning... analogous to the scientists' laws of Nature, whilst the axioms play the role of initial conditions. We are not free to pick any axioms... They must be logically consistent...
** John D. Barrow, Theories of Everything: The Quest for Ultimate Explanation (1991)
* The theoretical view of the actual universe, if it is in correspondence to our reasoning, is the following. The curvature of space is variable in time and place, according to the distribution of matter, but we may roughly approximate it by means of a spherical space. ...this view is logically consistent, and from the standpoint of the general theory of relativity [is most obvious] lies nearest at hand; whether, from the standpoint of present astronomical knowledge, it is tenable, will not be discussed here. In order to arrive at this consistent view, we admittedly had to introduce an extension of the field equations of gravitation, which is not justified by our actual knowledge of gravitation. It is to be emphasized, however, that a positive curvature of space is given by our results, even if the supplementary term [cosmological constant] is not introduced. The term is necessary only for the purpose of making possible a quasi-static distribution of matter, as required by the fact of the small velocity of the stars.
** Albert Einstein, "Cosmological Considerations in the General Theory of Relativity," Königlich Preußische Akademie der Wissenschaften (1917) 142-152, as quoted in The Collected Papers of Albert Einstein Vol. 6: The Berlin Years: Writings, 1914-1917 p. 431-432
* A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines. With consistency a great soul has simply nothing to do. He may as well concern himself with his shadow on the wall. Speak what you think now in hard words, and to-morrow speak what to-morrow thinks in hard words again, though it contradict every thing you said to-day. — 'Ah, so you shall be sure to be misunderstood.' — Is it so bad, then, to be misunderstood? Pythagoras was misunderstood, and Socrates, and Jesus, and Luther, and Copernicus, and Galileo, and Newton, and every pure and wise spirit that ever took flesh. To be great is to be misunderstood.
** Ralph Waldo Emerson, Self Reliance (1841).
* Consistency is contrary to nature, contrary to life. The only completely consistent people are the dead.
** Aldous Huxley, "Wordsworth in the Tropics" in Do What You Will (1929).
* Consistency is a virtue for trains: what we want from a philosopher is insights, whether he comes by them consistently or not.
** Stephen Vizinczey, "Good Faith and Bad" in London Sunday Telegraph (4/21/1974); reprinted in Truth and Lies in Literature (1986).
* Consistency is the last refuge of the unimaginative.
** Oscar Wilde, "The Relation of Dress to Art" in Pall Mall Gazette (2/28/1885); reprinted in Aristotle at Afternoon Tea:The Rare Oscar Wilde (1991).
* Consistency is the enemy of enterprise, just as symmetry is the enemy of art.
** George Bernard Shaw, quoted by Michael Holroyd in Bernard Shaw: The Lure of Fantasy (1991).
* The test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.
** F. Scott Fitzgerald, "The Crack-Up" in Esquire (2/36).
* If a person never contradicts himself, it must be that he says nothing.
** Miguel de Unamuno, quoted by Douglas R. Hofstadter in Godel, Escher, Bach (1979).
* Consistency requires you to be as ignorant today as you were a year ago.
** Bernard Berenson, Notebook (1892).
* Of course I'm inconsistent! Only logicians and cretins are consistent!
** Tom Robbins, Even Cowgirls Get The Blues (1976); spoken by the character "The Chink".
* A silly ass … wrote a paper to prove me inconsistent. … Inconsistency is the bugbear of fools! I wouldn't give a damn for a fellow who couldn't change his mind with a change of conditions.
** John Arbuthnot "Jacky" Fisher, British Admiral and First Sea Lord, in a letter to former Prime Minister Arthur Balfour (ndg); reported in Arthur J. Marder, From the Dreadnought to Scapa Flow: The Royal Navy in the Fisher Era, 1904-1919. (1961-1965); quoted by Robert K. Massie in Deadnought: Britain, Germany and the Comiing of the Great War (1991).
* I have forced myself to contradict myself in order to avoid conforming to my own tastes.
** Marchel Duchamp, quoted by Harriet & Sidney Janis in "Marchel Duchamp: Anti-Artist" in View magazine (3/21/45); reprinted in Robert Motherwell, Dada Painters and Poets (1951).
* When my information changes, I alter my conclusions. What do you do, sir?
** John Maynard Keynes, Reply to a criticism during the Great Depression of having changed his position on monetary policy, as quoted in "The Keynes Centenary" by Paul Samuelson, in The Economist Vol. 287 (1983), p. 19; later in The Collected Scientific Papers of Paul Samuelson, Volume 5 (1986), p. 275; also in "Understanding Political Development: an Analytic Study" (1987) by Myron Weiner, Samuel P. Huntington and Gabriel Abraham Almond, p. xxiv; this has also been paraphrased as "When the facts change, I change my mind. What do you do, sir?"
* The problem with being consistent is that there are lots of ways to be consistent, and they're all inconsistent with each other.
** Larry Wall, message-ID <20050516005559.GC26184@wall.org>, to perl6-language mailing-list.
* Psychotics are consistently inconsistent. The essence of sanity is to be inconsistently inconsistent.
** Larry Wall, Usenet article <199809041918.MAA06850@wall.org> (1998)
* Do I contradict myself? Very well then I contradict myself, (I am large, I contain multitudes.)
** Walt Whitman, Song of Myself, section 51, Leaves of Grass.

### Hoyt's New Cyclopedia Of Practical Quotations

    Quotes reported in Hoyt's New Cyclopedia Of Practical Quotations (1922), p. 132.
* Of right and wrong he taught Truths as refin'd as ever Athens heard; And (strange to tell) he practis'd what he preach'd.
** John Armstrong, Art of Preserving Health (1744), Book IV, line 302.
* Tush! Tush! my lassie, such thoughts resigne, Comparisons are cruele: Fine pictures suit in frames as fine, Consistencies a jewell. For thee and me coarse cloathes are best, Rude folks in homelye raiment drest, Wife Joan and goodman Robin.
** Jolly Robyn, Roughhead (fake ballad; appeared in American Newspaper, 1867).
* Nemo doctus unquam mutationem consilii inconstantiam dixit esse.
** No well-informed person has declared a change of opinion to be inconstancy.
** Cicero, Epigram ad Atticum, Book XVI. 7.
* Gineral C. is a dreffle smart man: He's been on all sides that give places or pelf; But consistency still wuz a part of his plan; He's been true to one party, and that is, himself;— So John P. Robinson, he Sez he shall vote for Gineral C.
** James Russell Lowell, The Biglow Papers, Series I. No. 3.
* Inconsistency is the only thing in which men are consistent.
** Horatio Smith, Tin Trumpet, Volume I, p. 273.
* Cantilenam eandem canis.
** You are harping on the same string.
** Terence, Phormio, III. 2. 10.