INFORMAL LOGIC XI.3, Fall 1989 Beardsley's Theory of Analogy EVELYN M. BARKER The University of Maryland 1. Is the Argument from Analogy a consequences of an "abdication of Fallacy? statesmanship."2 Kissinger cites historical analogy as the only basis for sound judg­ In the various editions of Practical Logic ment in international diplomacy: and Thinking Straight Monroe Beardsley History is the only experience on which pioneered informal logic, the assessment of statesmen can draw. But it does not teach reasoning techniques employed in actual its lessons automatically. It demonstrates the human situations. 1 Although acknowledg­ consequences of comparable situations, but ing the prominence of analogies in reason­ each generation has to determine what situa­ ing, he contended that analogy has some tions are in fact comparable. heuristic uses, but an argument based on one Such analogical arguments, as Kissinger is inherently fallacious: points out, are directed to finding suitable Analogies illustrate, and they lead to premises for wise and prudent action. hypotheses, but thinking in terms of analogy Beardsley's intellectualist approach limits becomes fallacious when the analogy is us­ rational argumentation to asserting premises ed as a reason for a principle. This fallacy as evidence for the truth of a conclusion. is called the "argument from analogy." Consequently he overlooks or misconceives (PL 107) the character of some forms of analogical Beardsley's view implies that no serious argument prevalent in practical reasoning. reasoner will use analogies between things It is misleading to speak of "the argument in drawing conclusions, or be persuaded by from analogy," as Beardsley does, as if all another's introduction of them. According­ are of the same kind. 3 ly, an important source of human Historical analogy, or "learning from knowledge is proscribed: historical analogy, experience," most nearly resembles reasoning based on direct comparison of arguments of inductive analogy: From past situations with the present. observed facts about previous instances one In practical reasoning, however, one draws an inference about what is likely to must often reach a judgment about the be true of a new instance sharing salient crucial features of some particular situation characteristics with them. Beardsley denies, in order to determine an appropriate course however, that inductive analogy is "a suc­ of action with respect to it. Analogizing its cesful kind of inductive argument" (TS2 features to another whose favorable or un­ 66). favorable outcome is already known, far Beardsley's theory of analogical reason­ from being fallacious, is at least common ing exemplifies overformalization in reduc­ sense and at most wisdom. For example, ing diverse kinds of analogy arguments to in a recent newspaper commentary head­ a single form, then assessing them all lined "A Stable World: Lessons of World fallacious because of the logical War II", Henry Kissinger compares the characteristics of that form. This results in current international situation with that a "denaturalized epistemology" of leading to World War II, warning of the dire analogical arguments, one with inappro- 186 Evelyn M. Barker priate concepts of knowledge, unrelated to define a fallacy as an argument that seduces reasoning techniques successfully employed one into thinking that the evidence provid­ in a range of actual situations. ed by its premises suffices for the truth of In order to track Beardsley's claim that its conclusion. an analogical argument is inherently fallacious, we must have in view his general theory of argument. Like many, he divides 2. Beardsley's Formalization of arguments into two exclusive kinds: deduc­ Analogical Reasoning. tive and inductive. A deductive argument makes the claim (correctly or incorrectly) Beardsley first formulated the principle that the truth of its conclusion follows of analogical argument in this way: "If X necessarily from the truth of the premises, and Y have a number of characteristics in because the argument is formally valid. He common, it is likely that any further calls all nondeductive arguments inductive: characteristics found in Y will also be found Such arguments make a lesser claim that in X." (PL 108) Few if any analogical "the evidence is sufficient to make the con­ arguments make such a sweeeping claim. clusion, at the very least, more likely to be He subsequently toned down the conclusion, true than false." (PL 197-203, TS228-29, schematizing the argument as follows: TS423-27) X and Y both have certain characteristics He insists that "any compelling argu­ a, b, c ... And it is known that Y also has ment must be one of these kinds, and another characteristic q. Therefore: X has moreover, it must conform to the standards the characteristic q. (TS2 65) of its kind." (PL 197). As Beardsley His reason for calling the analogical describes the argument from analogy, it is argument fallacious remains constant, a neither formally valid, nor does it fit his two thesis we may call the Principle of Infinite models of inductive reasoning, explanatory or Indefinite Variability, italicized by me hypothesis and inductive generalization. Not below: surprisingly, an analogical argument fulfills Beardsley'S conception of a fallacy: .. .if two things have a good deal in com­ mon ... the likeness may justify a further in­ An argument is a good one only if it pro­ vestigation to see whether they actually do ceeds in accordance with some rule of in­ have more in common. But it does not justify ference and thus can be justified by appeal our believing that they have more in com­ to that rule. If it purports to conform to a mon without the further investigation. No rule of inference, and thus acquires some matter how many characteristics a pair of plausibility, though in fact it violates that things have in common, there may be any rule, then it is said to be fallacious, or to number of other ways in which they are dif­ contain a fallacy. (TS4 26) ferent. (PL 108, TS2 66) As we shall see, the analogical argument With a little logic-chopping it is quite turns out not to have a justifying "rule of true that any two things, even identical inference" of its very own, or more exact­ twins, can readily be shown to have an in­ ly, its "rule of inference" contradicts a definitely large number of different principle Beardsley enunciates. In defining characteristics. But this logical point is ir­ a fallacy relative to its peculiar' 'rule of in­ relevant to whether there are significant ference" Beardsley betrays a formalistic similarities between the things analogized view of what constitutes "good argument" on which a reasonable judgment affirming as well as what constitutes a "fallacy". A an additional similarity may be based. In­ broader conception of both need make no ductive reasoning is useful because observ­ reference to the existence of a peculiar' 'rule ed similarities enable us to to make predic­ of inference." For example, one could tions about the future, which eventually are Beardsley on Analogy 187 confirmed or disconfirmed. tween blue-eyed parents and their offspring: In holding that analogical reasoning is fallacious because a conclusion may tum out John's parents both have blue eyes, and so do Jim's; John has blue eyes; therefore, Jim in fact to be false, Beardsley applies a must have blue eyes. (TS2 66) stricter standard to it than to ordinary in­ ductive reasoning-one appropriate to Beardsley's comparison of these two deductive reasoning. A "good" deductive arguments shows that they have the same argument has both 1) a valid logical form logical form, but that form is of such a kind and 2) true premises, so that the truth of that the premises may be true without the the conclusion follows necessarily from the conclusion also being true, that is, the argu­ truth of the premises. In effect, he accuses ment is formally invalid. In the first, we the analogical argument form of being in­ would not be surprised by the falsity of the valid, so that the truth of its premises does conclusion; in the second, we would be. If not guarantee the truth of its conclusion. But we insist on interpreting the argument from an analogical argument need not, and usual­ analogy as making a deductive claim, which ly does not, make that deductive claim. requires a valid argument form as well as Beardsley's formalization of the true premises, we would indeed have to call analogical argument tempts one to suppose it fallacious. the assumed resemblances a, b, c and the But the issue is, should we view' 'the inferred resemblance q are independent analogical argument" as making a deduc­ variables. Yet Beardsley's own definition tive claim that the conclusion follows of an analogy points out that they are all necessarily from the premises? Since interconnected: An analogy is an "extend­ analogical arguments are based on the ed simile" in which two things are com­ characteristics of the referents of the two pared in terms of the structural relationships terms analogized, the semantic interpreta­ holding between their characteristics or tion of the terms drives the argument rather part-whole relationships (PL 105-6). This than the logical form of the argument interrelatedness among the resemblances statements. The "must be" can reasonably mentioned in the premises tends to justify be understood as the less insistent "most an inference about a further resemblance. 4 likely" of an inductive claim. An invalid Like inductive reasoning generally, an deductive argument readily converts into a inductive analogy is not based merely on respectable inductive argument, as many in­ its stated premises but on all our knowledge troductory logic books say. If this is the about the world. The grounds for the argu­ case, an analogical argument, rather than ment include our independent knowledge being inherently fallacious, has more or less about the things analogized and the weight depending on what we know about characteristics attributed to them.