I have argued that the key to understanding structuralism and functionalism lies in look- ing at local structure/function disputes. These disputes are empirical disagreements about the answers to particular why-questions. Once this is understood, the need to char- acterize structuralism and functionalism as high-level positions is lessened. The sub- stance of my view is now on the table. It only remains to contrast my approach with another recent attempt to analyze structuralism and functionalism.
Sandy Boucher (2015) has recently defended the view that structuralism and function- alism should be understood as stances sensu van Fraassen (2002). It is not incompatible with my view that there should exist structuralist and functionalist stances of the sort Boucher describes. As such, our accounts are not in direct conflict. However, we disagree
local structure/function disputes to be most important and to be explicable inde- pendently of stances, while Boucher sees structuralist and functionalist stances as driving the disputes. Moreover, Boucher’s defense of the stance view raises a serious objection to the account I have developed. As such, it is worth considering.
A stance, according to Boucher (2015, 388), has five key properties. First, it is a cluster of attitudes and not a set of beliefs (nor is it reducible to a set of beliefs). Second, as a cluster of attitudes, a stance can be adopted but not believed. Third, because a stance is a cluster of attitudes, it is not propositional and therefore not truth-apt. Fourth, adoption of a stance is driven by one’s values (epistemic and non-epistemic). Fifth, adoption of a stance is justified pragmatically rather than epistemically.
The appeal of thinking of structuralism and functionalism as stances stems from their persistence across radical theory change. It seems we can meaningfully identify both structuralists (Geoffroy, Owen, Thompson, Goldschmidt, Alberch, Newman) and func- tionalists (Lamarck, Cuvier, Darwin, Minchin, Dobzhansky, Dennett, Carroll) across the last 200+ years of biological science. But our understanding of both structure and function has changed dramatically over this time. The worry is that any belief about the relation between structure and function that could survive the last 200 years of theory change in biology must be vague to the point of vacuity. If there is anything linking those biologists we call functionalists and those we call structuralists, then it must be something other than shared beliefs. And the best candidate seems to be a stance (Boucher 2015, 393).
This argument against the possibility of finding any contentful beliefs that all struc- turalists or all functionalists share casts doubt on my attempt in the foregoing to give a
general characterization of structure/function disputes. The fact that my analysis of local structure/function disputes involved taking on board aspects of contemporary evolu- tionary theory only furthers this worry. It is clearly not applicable in the form developed above to the various structuralists and functionalists who were not transmutationists (i.e. who rejected the possibility of evolutionary change).
These worries can be defused by separating out two projects I have been engaged in this chapter. One project is to clarify the nature of contemporary structure/function dis- putes. Given that all serious biologists today accept evolutionary theory in some form, it is useful to understand the specific nature of the structure/function disputes in which they are engaged, even at the expense of losing some historical generality.
At the same time (second project), I have attempted to capture what did remain con- stant in structure/function disputes across the Darwinian revolution. This is the analysis given in Sections 5.2 and 5.3, where I showed that such disputes were not over the ex- planatory priority of structure or function, but over the role of function in explaining structure. I already argued there that this question is substantive even in the absence of a shared background theory. Understanding structuralism and functionalism in terms of the distinction between structuralist and functionalist explanations eliminates the need to think of them in terms of stances.
This leaves open the question of whether my claims about the priority of local struc- ture/function disputes apply to pre-Darwinian structuralists and functionalists. Such bi- ologists obviously did not have arguments over the relative roles of the generation of
they did engage in local structure/function disputes. Consider the following two why- questions:
(W6) Why do the dugong’s fin, bat’s wing, and mole’s forelimb share the same underlying structure, rather than have different underlying structures? (W7) Why is the dugong’s forelimb a fin rather than a wing?
Richard Owen would answer W6 by invoking the vertebrate archetype that all three organisms share, and he would answer W7 in terms of the dugong’s aquatic mode of life. Georges Cuvier, by contrast, would answer both questions in terms of the organisms’ modes of life (conditions of existence). While these answers are not in terms of the gen- eration or spread of variation, they are nonetheless recognizably structuralist Owen’s an- swer to W6) or functionalist (Owen’s answer to W7; Cuvier’s answers to W6 and W7) in a broader sense.
In Section 5.2, the issue was raised that structuralists have, historically, offered quite different explanations of structure. These explanations were primarily unified in virtue of not being functional. In an evolutionary context, however, we can recognize a greater unity to structuralist explanations: they invoke properties of the generation of variation to explain evolutionary direction. More work is required to determine whether a similar unity can be found for pre-Darwinian structuralism—perhaps in terms of non-functional restrictions on possible form. I think the prospects are promising, but it is possible that it was only with the Darwinian revolution (and subsequent developments) that structural- ist approaches came to be unified in this way. Deciding between these two possibilities would require deep historical analysis that is beyond the scope of this chapter.
5.8 RECAPITULATION
In this paper, I have attempted to provide an analysis of structure/function disputes in biology that (a) accounts for the persistence of these disputes across 200+ years without rendering structuralism and functionalism vacuous and (b) explains the nature of con- temporary structure/function disputes, which occur within the context of evolutionary theory. The key claims I have defended are:
(1) Structuralism and functionalism are best characterized in terms of the role they ascribe of function in explaining structure. That is, they share the same explanandum, but differ over the explanans (Section 5.2).
(2) As a consequence of (1), structuralism and functionalism should not be un- derstood as disagreeing over the explanatory priority of structure or func- tion (Section 5.2).
(3) Darwin, though he substantially sophisticated the resources available to the functionalist and in doing so deprived structuralists of one of their strong- est arguments, did not change the central issue identified in (1) (Section 5.3). (4) As a consequence of (3), structure/function disputes can be understood as persisting across the Darwinian revolution (Section 5.3). This does not re-
(5) In the context of evolutionary theory, structure/function disputes are gen- erated when disagreements about the generation of variation lead to disa- greements about the sources of directional evolutionary change (Section 5.5).
(6) In the context of evolutionary theory, local structure/function disputes take the form of divergent answers to contrastive why-questions. Functionalist answers to these why-questions invoke the spread of variation, while struc- turalist answers invoke the generation of variation (Section 5.6).
(7) These notions of functionalist and structuralist answers to particular con- trastive why-questions are prior to understandings of structuralism and functionalism that transcend such local contexts, in the sense that the latter should be characterized in terms of the former (Section 5.6). It is an open question whether this point applies to pre-Darwinian structuralists and functionalists (Section 5.7).
(8) One particularly interesting higher-level form of structuralism is methodo- logical structuralism, which is a counterpart to methodological functional- ism (adaptationism). Methodological structuralism is worthy of further philosophical investigation (Section 5.6).