by Antony Flew
1.20 The same personally challenging point, that contradiction must be intolerable to anyone who really cares about truth, can, with the help of a little demonstration, be made more elaborately. Anyone inclined to bridle against such logic-chopping can without serious loss skip the next four paragraphs. The promised, or threatened, demonstration was apparently first mounted in the 1200s of our era either by Duns Scotus (c. 1266–1300) or by one of his pupils. (It is, by the way, ultimately to the uninhibited polemics of the philosophical opponents of the great Duns Scotus that we all owe our word “dunce.” There must be some moral here!)
1.21 The demonstration goes like this: First, take as your personal premise a contradiction of your choice. I take for mine the conjunction of the two propositions: (1) The Declaration of Independence was made in 1776; and (2) The Declaration of Independence was not made in 1776. Now choose, equally freely, any false proposition. I choose: Elvis Presley is alive and well. Next, take one half of the initial contradiction as a separate premise. From The Declaration of Independence was made in 1776 it follows that The Declaration of Independence was made in 1776 and/or Elvis Presley is alive and well.
1.22 Thus, given that for whatever x may be, x is true, then for the same value of x and for any value of y it follows necessarily that x and/or y is true. The only, but sufficient, justification for employing the symbols x and y—rather than the awkward verbal alternatives something, the same something, something else, and the same something else—is that the point can thereby be made more briefly, more clearly, and more elegantly. The object is, as it always should be, to promote understanding. What needs to be understood is that so far it has been shown that, from my arbitrarily chosen contradictory premise, it follows that The Declaration of Independence was made in 1776 and/or Elvis Presley is alive and well. So far so unexceptionable, and altogether unexciting.
1.23 But now we consider the second half of the initial contradiction: The Declaration of Independence was not made in 1776. Taking this as one premise and the conclusion reached at the end of paragraph 1.21 as the other, it becomes impossible to avoid the false conclusion that Elvis Presley is alive and well. For to deny this while asserting these two premises would be to contradict oneself.
1.24 We thus have an absolutely general and absolutely compulsive demonstration that from any contradiction which you like to choose, any other proposition, equally arbitrarily chosen, follows necessarily. By the same token, the negation of that other, arbitrarily chosen, proposition must also follow, equally necessarily. We can by the same method also deduce the opposite conclusion: Elvis Presley is not alive and well. Both every proposition and its negation thus follows from any contradiction. Hence, if contradiction is tolerated, then, in a very literal sense, anything goes. This situation must itself be totally intolerable to anyone who has any concern at all to know what is in fact true and to avoid either saying or implying what is in fact false. If all this seems pedantic, recall Bertrand Russell’s mischievous definition of a pedant: “A person who prefers his statements to be true.”
1.25 Generally, therefore, when someone with pretensions to be a thinker either denounces the restrictions of logic or remains unmoved by charges of self-contradiction, we know what to think. Thomas Aquinas (c. 1225–1274) understood as well as any man that the saints and the prophets may speak of mysteries. Yet, having a grip on logical fundamentals, Aquinas never forgot that there can be no place for self-contradiction in any authentic quest for truth. Thus, in considering the omnipotence to be attributed to his God, he took account of what is in modern terms the distinction between logical and other senses of “impossibility.” A suggestion is said to be logically impossible if that suggestion contains or implies a self-contradiction, or is perhaps otherwise incoherent and unintelligible. But a suggestion that is not in this sense logically impossible may be ruled out by the actual laws of nature and hence be factually impossible. As Aquinas put it in the Summa Theologica: “Whatever does not imply a contradiction is, consequently, among those possibilities in virtue of which God is described as omnipotent. But what does imply a contradiction is not subsumed under the divine omnipotence . . .” (I Q25 A3). You cannot, he might have said, transmute some incoherent mixture of words into sense merely by introducing the three-letter word “God” to be its grammatical subject.
1.26 One place where this distinction and this insight is indispensable is in the discussion of what theists call “The Problem of Evil.” This is the theists’ problem of trying to show that they are not contradicting themselves in maintaining both that there is, as indeed there is, much evil in the Universe and that the Universe is the work of an all-powerful, all-good God. It is not a bit of use to appeal here to what are, the Universe being as it happens to be, factual impossibilities. The only hope for the theist is to try to show that it would be logically impossible to have the actual goods without the actual evils, as it is, for instance, logically impossible to have the good of forgiveness without the evil of an injury to be forgiven. It is logically impossible because it is self-contradictory to speak of forgiving a nonexistent injury. For the theist it must be almost blasphemous to argue here, along lines I once saw indicated by one of a series of posters described as constituting The Wayside Pulpit: “If it never rained, there would be no hay to make when the sun shone.”
1.27 The most fundamental kind of confusion about contradiction is an intellectual malpractice that Karl Marx (1818–1883) and Friedrich Engels (1820–1895) derived from their study of the enormously influential German philosopher G. W. F. Hegel (1770–1831). This is the malpractice of thinking of contradictions not only as occurring in discourse, but also as involved in the interactions of physical objects. Thus, in the essay On Contradiction supposedly written by Mao Tse-tung, we can read: “The supersession of the old by the new is the universal, forever inviolable law of the world. . . . Everything contains a contradiction between its new aspect and its old aspect, which constitutes a series of intricate struggles. . . . At the moment when the new aspect has won the dominant position over the old aspect, the quality of the old thing changes into the quality of the new thing. Thus the quality of a thing is mainly determined by the principal aspect of the contradiction that has won the dominant position.”
1.28 A contradiction in this regrettable usage is thus not a verbal contradiction, but a conflict or a tension in or between things or people. Once these categories are properly distinguished, the apparent justification for employing the same word in two utterly different cases disappears. To the extent that this usage helps to collapse or to confound a categorical distinction, it is to be deplored. This same usage encourages talk of fruitful or even nonantagonistic contradictions, contradictions that are welcome, or at least venial. (Mao Tse-tung himself continued, speaking of the “contradiction” between town and country: “But in a socialist nation and in our revolutionary bases such an antagonistic contradiction becomes a nonantagonistic contradiction; and it will disappear when a communist society is realized. . . .”)
1.29 But talk of fruitful (if not, perhaps, of nonantagonistic) contradictions may have quite a different source. The contradictions then referred to are genuine verbal or symbolic contradictions, and the fruit offered has to be picked by laboring to remove the contradiction. The vital point for us is that this fruitfulness presupposes the removal of the contradiction. It is only insofar as contradiction is recognized to be intolerable that the labors which may provide fruit can begin.
1.30 Consider, for instance, disagreements about whether or not some country is democratically governed. Very obviously the party who asserts that it is appears to be contradicting the party who asserts that it is not. But perhaps these two disputants are employing the key word “democratic” in different senses. For one of them the criteria for a democracy may be that the rulers should have been popularly elected into office and—much more important—that it should be possible in due course to vote them out. For the other one the criterion may be that favored by rul
ers describing their fiefs as people’s democracies, namely, that these rulers are working to promote the best interests of those whom they rule. One by now rather ancient, yet still remarkably clear expression of this conception of democracy was provided by Janos Kadar, addressing the Hungarian National Assembly on May 11, 1957, one year after a Soviet army of intervention had installed him into office as prime minister: “The task of the leaders is not to put into effect the wishes and will of the masses. . . . The task of the leaders is to accomplish the interests of the masses.” This statement may profitably be compared and contrasted with that made by Abu Zuhair Yahya, prime minister of Iraq in 1968: “I came in on a tank, and only tanks will get me out” (quoted in Luttwak 1969, p. 146).
1.31 Because of the Hegelian or Hegelian-Marxist confusion involved in speaking of contradictions in things and because salutary challenges to resolve seeming but not actual contradictions may be preposterously misconstrued as reasons for rating actual contradictions as in themselves good, contradiction sometimes wins an undeservedly favorable press. Similar confusions and misunderstandings often get an understandably bad press for logic.
1.32 The first of these misunderstandings hinges on a failure to distinguish two senses of the word “logic.” One is primary. It is the sense in which the word has been employed in this chapter up till now. The other is secondary and derivative. This is the sense in which it is true to say that Aristotle (384–322 B.C.E.), in the works grouped into what was later called the Organon, created “Logic” as an academic discipline. These two senses are most conveniently distinguished by printing the word with an initial capital whenever it is used in the second sense.
1.33 The general mistake here is that of expecting any study of that kind to be either necessary or sufficient to improve the practice to which it is directed. The musicologist does not through his musicology become a better executant. Nor does being a great performer immediately qualify one to be a musicologist. The particular point about “Logic” and “logic” was made in the late 1600s by John Locke (1632–1704) in his Essay concerning Human Understanding: “God has not been so sparing to men to make them barely two-legged creatures, and left it to Aristotle to make them rational; . . .” (IV [xvii] 4).
1.34 On the contrary: “Logic,” as the theoretical study of the forms and principles of argument, could only begin among and be pursued by people possessing a good practical capacity to separate valid from invalid arguments. In fact, its first strong and extensive development was among the ancient Greeks and, in particular, among the supremely argumentative Athenians. (For a lively and instructive study of the peculiarities of these Greeks, which made possible the origination of so much that was essential to the development of our modern world, see Alan Cromer’s Uncommon Sense: The Heretical Nature of Science [1993], especially chapters 4–6.) The present book, which is intended to help people to improve their thinking, is not an essay in theoretical Logic. It is instead an exercise in logical coaching. Such an exercise may be beneficial even though neither the coach nor the coached have or acquire any familiarity with the calculi of Logic. But it could not even begin, much less be beneficial, unless all concerned possessed at least some minimal competence in discerning soundness in argument. Without that you could not even understand the coaching.
1.35 The second and much more important reason why logic gets a bad press is that it is confused with various things which have nothing to do with it. Consider, for instance, the contrast and the possible conflict between two opposite approaches to politics and to society. On the one side are those who, like Plato (c. 428–c. 348 B.C.E.), want, as he put it in his dialogue The Republic, “to start with a clean canvas.” A good example of this approach was provided by the Jacobins during the great French Revolution of 1789. They replaced all the previous subdivisions of France by eighty-three Departments, all roughly equal in area and each with its own administrative center. They also introduced a new calendar of twelve months with freshly minted names, and all the months were divided into three decads of ten days each. (A special arrangement was made to accommodate the surplus five days.) And so on. On the opposite side are those, like Aristotle, who prefer to start from wherever they are, seeing improvement as a matter of natural growth and development. Reformers of the first kind are likely to long for utopia and to have a penchant for wholesale operations. Reformers of the second kind do not expect anything to be perfect and believe that whatever progress can be made has to be made piecemeal. They understand, with the great German philosopher Immanuel Kant (1724–1804), that “out of the crooked timber of humanity no straight thing can ever be made.”
1.36 Especially in the context of thinking about the French Revolution of 1789, the first great social revolution of the modern period, Edmund Burke (1729–1797)* is often seen as representative of the second approach. This approach is sometimes believed by English people to be characteristically English, although Burke himself was born and educated in Ireland. By contrast, the Abbé Sieyès,* who contrived to survive when so many of the other revolutionaries were killed, is seen as representative of the first approach, an approach which is in the same circles seen as characteristically French. Neither of these approaches is as such either logical or illogical, although particular spokespersons on one side or the other may well be logical or illogical. But when confronted with the argument of the Abbé Sieyès against legislative second chambers, his supporters are apt to applaud his famous apothegm as a fine specimen of Gallic logic while his opponents decry it upon exactly the same ground. What he said was: “If the second chamber agrees with the first, it is superfluous, whereas if it disagrees with it, it is obnoxious.”
1.37 It is not for us here to decide whether this statement is especially Gallic. We do, however, need to notice that it certainly is not especially logical. If someone accepted the two conditional propositions so dogmatically asserted, then it would, of course, be illogical for that person to refuse to allow that any second chamber agreeing with the first must be superfluous and that any second chamber disagreeing with the first must be obnoxious. Yet there is no intellectual or other merit in simply asserting these drastic propositions. By doing so you make the totalitarian assumption, without providing any supporting evidence, that all dissent from any decision made by the first chamber must be immediately and automatically overridden. This is an assumption which no one has any business to make tacitly and without supporting argument. When such a brilliant refusal to examine the case for the opposition is presented as a model of logic, then there is every excuse to be suspicious. But it is not in this interpretation that we are laboring to make ourselves more logical.
1.38 We have shown why contradiction ought to be unacceptable and that logic is connected, albeit indirectly, with truth. It should now be less misleading to insist again upon the fundamental difference between questions about validity and questions about truth. To fix this in mind we need one or two dull, undistracting, naggingly unforgettable examples. Consider as premises the two propositions: All philosophers are lifelong bachelors and King Henry VIII of England was a philosopher. Both are false. But if they were true, then it would follow necessarily that King Henry VIII of England was a lifelong bachelor. Anyone who asserts the two false premises, yet denies the conclusion, would certainly be committing a self-contradiction. So now, since few people have less claim to have been lifelong bachelors than King Henry VIII, who was married six times, we have an example of a valid argument from false premises to a false conclusion.
1.39 Next, suppose that we substitute for the original second premise: President James Buchanan was a philosopher. Then, again, both premises will be false. The conclusion will be that President James Buchanan was a lifelong bachelor. Applying the same test as before, it is obvious that this is derived by a valid deductive argument. But this time the conclusion is true. Thus, we now have an example of a valid argument from false premises to a true conclusion.
1.40 Someone says: All Christians believe in an omnipoten
t and personal God, and Mother Teresa believed in an omnipotent and personal God. If we assume that these two propositions are true, are we entitled, taking them as our premises, to deduce the conclusion: Mother Teresa was a Christian? No, of course we are not. Certainly the conclusion is true. Yet the argument, considered as an argument, is, equally certainly, invalid. To make it valid, the first premise would have to be changed to read not All Christians, but All and only Christians. So the example offered, without that essential amendment, constitutes an example of an invalid argument to a conclusion which happens nevertheless to be true.
1.41 Suppose that some people have difficulty in appreciating that such an argument must be invalid, as indeed many people may have since they happen to know that its conclusion is in fact true. Then the natural and appropriate response is to summon up parallels to enable those who have this difficulty to appreciate that neither this nor any other argument of the same form can possibly be sound. You might as well argue, we might say, that given that All swans are white (which they are not), and given that President William Clinton is white (which, in terms of race, he is), then it follows necessarily that President William Clinton is a swan (which will scarcely do). Or, again, you might as well argue that given that All Communists claimed to be opposed to racism and given that Dr. Martin Luther King claimed to be opposed to racism, then it follows necessarily, Dr. Martin Luther King was a Communist.
1.42 When we produce such parallels, we are trying to bring out the invalidity of all arguments of one particular form: the form, that is, and whatever it is, which is shared by both the original specimen and all the genuine parallels which could be deployed. The main practical reasons why parallels have to be summoned is that people are put off by what they know or believe about particular propositions in particular arguments. Because we know or believe that the proposed conclusion is true, we become less alert to the possible weakness of the inference by which it is supposedly derived.