The Making of Arguments

go on shooting at the people, it would be better if he went on using flintlocks. Under the auspices of the Carnegie Institution an expert in business administration made an inquiry into the methods of teaching and research in physics at various American universities, and made recommendations based on the conduct of business establishments. A professor of physics in answer showed in how many ways the analogy between a business concern, whose end is profit, and a physical laboratory, whose end is the advancement of knowledge, is false and misleading. The expert had suggested a general research board to correlate researches; the professor cited the cases of Airy, the astronomer royal of England, who by his dominating position held back astronomical research in England for a generation, and of Sir Humphry Davy, who discouraged the work of Faraday, when the latter was his assistant. The expert suggested that apparatus could be passed on from one investigator to another: the professor replied that few men can use apparatus designed for some one else's purpose, and that the cost of reconstruction would exceed the cost of new machines. In short, he completely riddled the argument from analogy set up by the expert.27 A notable example of conclusive refutation of an argument based on a false analogy is to be found in William James's Ingersoll Lecture on Immortality. He took up the ordinary argument against the immortality of the soul, which, starting from the accepted physiological and psychological formula, "Thought is a function of the brain," reasons that therefore when the brain dies and decays, thought and consciousness die, too. This, then, is the objection to immortality; and the next thing in order for me is to try to make plain to you why I believe that it has in strict logic no deterrent power. I must show you that the fatal consequence is not coercive, as is commonly imagined; and that, even though our soul's life (as here below it is revealed to us) may be in literal strictness the function of a brain that perishes, yet it is not at all impossible, but on the contrary quite possible, that the life may still continue when the brain itself is dead. The supposed impossibility of its continuing comes from too superficial a look at the admitted fact of functional dependence. The moment we inquire more closely into the notion of functional dependence, and ask ourselves, for example, how many kinds of functional dependence there may be, we immediately perceive that there is one kind at least that does not exclude a life hereafter at all. The fatal conclusion of the physiologist flows from his assuming offhand another kind of functional dependence, and treating it as the only imaginable kind. When the physiologist who thinks that his science cuts off all hope of immortality pronounces the phrase, "Thought is a function of the brain," he thinks of the matter just as he thinks when he says, "Steam is a function of the teakettle," "Light is a function of the electric circuit," "Power is a function of the moving waterfall." In these latter cases the several material objects have the function of inwardly creating or engendering their effects, and their function must be called productive function. Just so, he thinks, it must be with the brain. Engendering consciousness in its interior, much as it engenders cholesterin and creatin and carbonic acid, its relation to our soul's life must also be called productive function. Of course, if such production be the function, then when the organ perishes, since the production can no longer continue, the soul must surely die. Such a conclusion as this is indeed inevitable from that particular conception of the facts. Rut in the world of physical nature productive function of this sort is not the only kind of function with which we are familiar. We have also releasing or permissive function; and we have transmissive function. The trigger of a crossbow has a releasing function: it removes the obstacle that holds the string, and lets the bow fly back to its natural shape. So when the hammer falls upon a detonating compound. By knocking out the inner molecular obstructions, it lets the constituent gases resume their normal bulk, and so permits the explosion to take place. In the case of a colored glass, a prism, or a refracting lens, we have transmissive function. The energy of the light, no matter how produced, is by the glass sifted and limited in color, and by the lens or prism determined to a certain path and shape. Similarly, the keys of an organ have only a transmissive function. They open successively the various pipes and let the wind in the air chest escape in various ways. The voices of the various pipes are constituted by the columns of air trembling as they emerge. But the air is not engendered in the organ. The organ proper, as distinguished from its air chest, is only an apparatus for letting portions of It loose upon the world in these peculiarly limited shapes. My thesis now is this: that, when we think of the law that thought is a function of the brain, we are not required to think of productive function only; we are entitled also to consider permissive or transmissive function. And this the ordinary psychophysiologist leaves out of account.28 The question of the validity of an analogy in reasoning is always, as here, whether the similarity on which the reasoning rests really runs between the two cases in hand, or is not merely a general resemblance expressed by some phrase or word which seems to mean more than it does. In other words, when you are testing an analogy, whether your own or an opponent's, make sure that the similarity is real for the present case. A picturesque figure of speech may add life to an argument, but it may also cover a gap in the reasoning. 36. Reasoning by Classification or Generalization. Obviously the strength of reasoning from analogy increases with the number of cases which you can point to as showing the similarity on which you rely, for you can then begin to generalize and classify. Analogy expresses our natural tendency to assimilate the new to the old, to interpret what is strange and unfamiliar in the light of what we already know. It may therefore be described as classification in the making. The resemblances which guide us are called analogies so long as they are newly seen, rare, or doubtful; but as the number of cases increases, analogy passes by insensible stages into established classification.29 An excellent example of this transition may be seen in the present state of the argument in favor of commission government: at first, as we have seen, it depended chiefly on reasoning from analogy; by this time enough cities have adopted the plan to make it possible to classify them, and so reason by generalization. Generalization and classification, it may be noted in passing, are two aspects of the same process of thought. When one passes from the individual facts to the larger fact which brings them together, as in the assertion, Members of the Phi Beta Kappa are good scholars, one makes a generalization; when one asserts of an individual the larger fact, as in the assertion, My brother is a good scholar (My brother belongs to the class Good Scholars), one makes a classification. When a classification or generalization is constant and familiar, it brings forth, by the natural economy of language, a name for the class or the principle; "federation," "deciduous trees," "emotion," "terminal moraine," are all names of classes; "attraction of gravity," "erosion," "degeneration," "natural selection," are names of principles which sum up acts of generalization. Almost always these names begin as figures of speech, but where they are used accurately they have a perfectly exact meaning. Darwin has given some account of this process of language: "It has been said that I speak of natural selection as an active power or deity, but who objects to an author speaking of the attraction of gravity as ruling the movements of planets? Every one knows what is meant by such metaphorical expressions, and they are almost necessary for brevity: so, again, it is difficult to avoid personifying the word 'Nature.' But I mean by Nature the aggregate action and product of many laws, and by laws the sequence of events as ascertained by us."30 When the facts intended to be meant by a phrase are thus carefully specified and delimited, the phrase ceases to be a figure of speech, and becomes the name of a class or of a principle. Generalization and classification always take place for purposes of reasoning;31 and reasoning which is dependent on them rests on the assumption that things are uniformly correlated in nature; when we throw things together into classes we assume that what is true for one member of a class, so far as it is a member of that class, is true to the same extent and for the purpose for which the class is made for all other members of that class. In practice a large part of our reasoning is through generalization and classification; and as we have seen, it has a more substantial basis than when we rest on an analogy. If you hear that your brother has been elected to the Phi Beta Kappa, you reason from the generalization that all members of the Phi Beta Kappa are high scholars to the inference that your brother must have taken high rank. When I see a gang of carpenters knocking off work at four o'clock in the afternoon, I infer that they must belong to the union, because I know that unions as a class have established an eight-hour day. If you were arguing that the standards for graduation from your college should be raised, you would try to show that each year enough men are graduated with low intellectual attainments to make a class large enough to generalize from. If you were arguing that your city should establish a municipal gymnasium, you would try to show that of the boys and young men brought before the police courts for petty mischief and more serious offenses almost all have lacked the chance to work off their animal spirits in a healthy way. Wherever you can thus establish your special case in a class which has known characteristics or consequences, you can then apply the characteristics and consequences of the class to your special case. "The whole object of any class name is to group together (for the purpose of making general assertions) individual members which are not only alike but different; and so to give unity in spite of difference."—A. Sidgwick, The Use of Words in Reasoning, London, 1901, p. 165.] Where the class is recognized as having definite characteristics or consequences, you can make your inference by showing that your case falls within the class. Sometimes the stress of your reasoning will come on making it clear that the consequence or characteristic on which your reasoning depends really belongs to the class. If, for example, you were arguing, as did the Class of '85 at Amherst College, that your college should return to something like the old-fashioned classical education, you would try to establish the fact that men who have had the old-fashioned classical education are as a rule characterized by intelligence, liberal culture, and open-mindedness. In such cases it is the generalization on which the class is based which is the difficult part of your task. In general, however, if you can show your readers that the present case belongs in a class of cases which can be recognized as belonging together by virtue of definable characteristics, you have established an excellent foundation for an inference based on those characteristics. 37. Reasoning by Causal Relation. Reasoning by generalization rises greatly in certainty, however, whenever you can show the workings of cause and effect. If a college