Reasons and Causes
One of the objections that critics have repeatedly directed against the Strong Program is that the commitment to causal, sociological explanation entails neglecting the role of reasons. The critics say that a Strong Program analysis involves disregarding the reasons that social actors themselves offer for their behavior. According to the critics these reasons can, on occasion, provide a sufficient explanation of the behavior and thus render redundant any attempt to construct a causal, sociological explanation. A recent example of this criticism is to be found in a 2006 paper by Sturm and Gigerenzer.7 The authors say: “Even after a strong sociological explanation has been given for the beliefs of a scientist, it remains sensible to ask: Very fine, but how are these beliefs connected to the scientist’s justificatory reasons? Can these reasons perhaps explain better why the scientist acquired the relevant beliefs?” (144). As the wording indicates, these critics assume that the candidate sociological explanation will have been constructed without any significant reference to the agent’s reasons. The critics wish to make good this alleged lack, and they put their money on finding cases where nothing more than the scientist’s own reasoning is needed to explain some pattern of scientific belief. The agent’s reasons, they say, can be the cause of their beliefs, and a proper explanation of these beliefs should be in terms of these reasons (141).
Does the causal explanation that I have put forward to account for my findings in the history of aerodynamics depend on, or result in, a lack of
serious attention to the agent’s reasons? I hope it will be evident that such a complaint is groundless. The problem I have posed, the central problem of the book, is a problem about the reasons that were used to justify a certain scientific judgment. I have attended closely to the reasons given by the actors in the story and subjected them to a close analysis. I fear, however, that critics will dismiss my discussion of scientific reasoning as mere window dressing. Thus Sturm and Gigerenzer say, “Mentioning that scientists claim to employ certain reasons or reasoning standards, and mentioning which ones these are, is not the same as taking these standards seriously—seriously in the sense that they are acknowledged as causes of the scientist’s acceptance or rejection of claims” (142). For these critics, nothing short of treating reasons as selfsufficient explanations will count as taking them seriously. This I certainly have not done and will not do because it would corrupt the analysis. Despite this, attending to the actor’s reasons has played a central role, even though the analysis culminates in a causal explanation. The actor’s reasons are not merely mentioned; they are given a substantial role. Consider the stated reasons offered by the British to justify their rejection of the ideal fluid approach, for example, their complaint that the origin of circulation must forever remain a mystery. These reasons certainly illuminate the British rejection. When the reasons are examined, however, it becomes clear they do not adequately explain the behavior of the British experts. This is not because the British had other “real” reasons. The inadequacy of the explanation is because their German counterparts understood the reasons that moved the British as well as the British did, but responded differently. Kelvin’s theorem was as familiar to Prandtl as it was to Taylor or Jeffreys. For me, therefore, taking reasons seriously, and assessing their causal role, requires asking why the same facts and the same theorems, that is, the same reasons, caused such divergent responses in the two groups of professionals.
Faced with a situation of this kind, where stated reasons underdetermine the response, should the historian look for a difference in the intellectual presuppositions behind the reasoning of the two groups? Perhaps this approach could uncover hidden premises and lead to an explanation of the different reactions. An appeal to presuppositions might keep the analysis within the realm of self-sufficient reasons in the way that the critics want. A search for presuppositions is certainly important in any historical analysis, and it has been a feature of my own procedure. As I have shown, such a search uncovers subtly different conceptions of an ideal fluid. The British experts treated an ideal fluid as a fluid of zero viscosity (p = 0), while their German counterparts treated it as the limit of a fluid of small viscosity (p ^ 0). The British drew a strong boundary between inviscid theory and viscous theory.
German-language work involved a weaker and differently positioned boundary. Thus von Mises was inclined to treat the objects of both the Euler and the Stokes equations as abstractions, while Prandtl was inclined to treat them both as realities. Despite their differences, both of these German-language thinkers placed viscous and inviscid fluids on a par with one another. This aligned the two against the more literal-minded realism of the British, who treated viscous fluids as real and inviscid fluids as unreal.
There can be no doubt, then, that identifying presuppositions of this kind deepens the analysis, but it still cannot furnish an explanation of the divergent responses of the British and the Germans. Presuppositions are simply reasons for reasons, so the real problem is postponed rather than solved. It merely leads to further questions: Where do the presuppositions come from? Why did the British and Germans have different presuppositions?
The point may be made in another way. I identified a sequence of judgments that informed the technical content of the aerodynamic knowledge of lift. At each point in the sequence the British experts jumped in one direction while the German experts jumped in the other. Such was the case regarding (1) the significance attached to the “arbitrary” value of the circulation,
(2) the meaning of the zero-drag result, (3) the importance of explaining the critical angle at which a wing stalled, (4) the reaction to the overoptimistic lift predictions derived from the theory of circulation, and (5) the problem of explaining the origin of the circulation around a wing within the confines of the theory of ideal fluids. The divergence of judgment on these questions was systematic, fundamental, and constitutive of the rival understandings of the two groups. It cannot be dismissed as a coincidence, but nor can it be explained by the divergent reasons themselves. The deployment of reason is the problem, not the solution. The phenomenon calls for a causal explanation, and that is what I have given.
So far I have described my procedure in terms of an apparent transition from reasons to causes. I have said, in effect, that my analysis may have started with reasons but it finished by my making an appeal to causes because reasons became equivocal. I justify the claim that the analysis is causal (and conforms to the Strong Program) by saying that an appeal to causes is, in the end, unavoidable. This argument is correct, but as a way of speaking it can generate problems. At best it is a provisional way to state the methodology behind the analysis.
The problem is that two modes of speech and two perspectives are in play: those of the actors and those of the analyst. Keeping both modes of speech in play may suggest that there are two different sorts of cause at work, namely, rational causes and sociological causes. Are we to conclude that reasons cause some of the behavior of the scientists under study but not all of it, so that the remainder has to be explained by sociological and nonrational causes? Does rationality provide a partial cause alongside other kinds of cause furnished, say, by the social context? Some such view may seem to be underwritten by the historian’s own investigative procedure or, at least, by the way the procedure is sometimes presented. First, it seems, reasons are examined and then, and only then, are sociological causes to be invoked (as if they were a residual category). But granted that the work of the historical analyst sometimes exhibits such a pattern, it would be wrong for the analyst to project this expository sequence into the picture of the historical actor and imagine that actors are, or may be, subject to a corresponding sequence of influences. I do not believe that a dualism of rational and sociological causes, which allegedly compete or alternate with one another, or supplement one another, can be the basis of a satisfactory perspective. It is eclectic and merely encourages baldly posed questions. Something more unified, and hence reductive, is called for. If the Strong Program is correct, then “rational causes,” which have so often been treated as sui generis, are really nothing more than a species of social causes.
Think of the confrontation between Lanchester and Bairstow when they clashed in public in 1915. Bairstow said that Lanchester could not explain why aircraft stalled, so his theory could not be taken seriously; Lanchester said that he did not need to explain this stalling because a theory of narrow scope could still be valuable within its limited domain. My claim is that, in tracing the arguments that Bairstow and Lanchester used against one another, a good historical analyst will, at the same time, be tracing the causal texture of their interaction. There will be no duality of rational and social causes and no transition from one to the other. A properly historical account of the interaction between Lanchester and Bairstow will be in terms of social causation from the outset. A unified, social-causal perspective of this kind can be sustained if the analyst focuses relentlessly on the credibility that the participants and their audience attach to the arguments that are being advanced. Why did the failure to explain the onset of a stall worry Bairstow in a way that it did not worry Lanchester? Why was Bairstow’s concern shared by other British experts but not, to the same degree, by Kutta, Prandtl, and other supporters of the circulatory theory in Germany? These are the questions that will expose the sociological basis of the power of reason, and these are the questions to which I have given answers.
The importance of credibility as a causal category, with its variable and distributed character, is at its most striking when the overall scene is brought into view, for example, the systematic divergence of the German and British responses to circulation. But actual or possible divergences of this kind are not confined to the large scale. They are a feature of every act of reason giving and every act of responding to reasons, whether interpersonal or intrapersonal, whether public or private. This is because, on its own, invoking and formulating reasons can never be sufficient to render a belief causally intelligible or a course of action causally explicable. Things may not look this way from the actor’s point of view. Sometimes the reasons that are advances in the course of an interaction are accepted by other actors as sufficient justification or explanation. But I am giving the analyst’s perspective. I am speaking here from the point of view of a historian or sociologist who is committed to giving a causal analysis of a passage of interaction and behavior. Of course, critics say the claim that reasons are never sufficient is mere dogmatism or the result of an irresponsible generalization. Like others before them, Sturm and Gigerenzer see here nothing but a lack of prudence on the part of supporters of the Strong Program.8 They think it is more judicious to allow that reasons sometimes explain rather than never explain. In fact my claim is not dogmatic; it is made on the basis of a general and principled argument. The argument comes from Wittgenstein’s analysis of rule following and has explicitly informed the Strong Program from the outset.9 Because the argument is so important, and so often misunderstood or ignored, I rehearse it here and then connect it to my overall analysis.