The comparative method grants epistemic access to the biological past. Comparing lineages provides empirical traction on both hypotheses about particular lineages and models of trait evolution. Understanding this evidential role is important. Although philosophers have recently turned their attention to relations of descent, little work exists exploring the status of evidence from convergences. I argue that, where they exist, convergences play a central role in the confirmation of adaptive hypotheses. I focus on ‘analogous inferences’, show how such inferences ought to (...) be analysed and suggest three methods for strengthening their evidential weight. 1 Introduction2 Analogous Inferences2.1 Adaptive explanations and analogies2.2 Analogous inferences2.3 Scope, grain, and specificity3 Parallel Modelling, Integrated Explanations, and Convergent Modelling3.1 Parallel modelling3.2 Integrated explanations3.1 Convergent modelling4 Conclusion. (shrink)

Philosophers differ widely in the extent to which they condone the exploration of the realms of possibilia. Some are very enamoured of thought experiments in which human intuition is trained upon the products of human imagination. Others are much more sceptical of the fruits of such purely cognitive explorations. That said, it is clear that human beings cannot dispense with modal speculation altogether. Rationality rests upon the ability to make decisions and that in turn rests upon the ability to learn (...) about what is possible and what is probable. Thus, on pain of irrationality, we must have some means of exploring other possible worlds. Thankfully, intuition is not the only aid we have at our disposal. Science also is in the business of finding regularities, which hold counterfactually. Scientific theory tells us about the likelihood of particular outcomes flowing from particular processes given particular background conditions. Thus, it also tells us about the contents of 1 of 21 other possible worlds. One consequence of the possibility of such inferences has been a theoretical interest, not just in the contents, but also in the geography of the domain of all possibly worlds. Metaphysicians, epistemologists and philosophers of language are very familiar with locutions such as “nearby possible worlds”. Similarly, evolutionary theory tells us that there is little chance of us discovering an organism that is mammal-like in most respects except in having six limbs. It’s not that we know such an organism to be impossible, but rather that we think it would be the product of an evolutionary history very different to the actual history of life on earth. Put another way, such organisms would be denizens of distant possible worlds. Clearly then, both biology and philosophy have ample motivation to be interested in the reasoning and evidence that supports such claims. Seemingly, in both disciplines there is a certain lure to this modal cartography, but ought we in fact to be convinced of its merits? Is it science or philosophy or not a good example of either? What sort of problems can it solve? What sort of problems will it create? How might we test its accuracy? In his excellent book Theoretical Morphology: The Concept and Its Applications, George McGhee provides an admirable introduction to the complex theoretical landscape surrounding the exploration of possible biological form. (shrink)

The emerging discipline of evolutionary developmental biology has opened up many new lines of investigation into morphological evolution. Here I explore how two of the core theoretical concepts in ‘evo-devo’ – modularity and homology – apply to evolutionary psychology. I distinguish three sorts of module – developmental, functional and mental modules and argue that mental modules need only be ‘virtual’ functional modules. Evolutionary psychologists have argued that separate mental modules are solutions to separate evolutionary problems. I argue that the structure (...) of developmental modules in an organism helps determine what counts as a separate evolutionary problem for that organism. I suggest that homology as an organizing principle for research in evolutionary psychology, has been severely neglected in favor of analogy (adaptive function). I consider some arguments suggesting that determining homology is less epistemically demanding than determining adaptive function and argue that psychological categories defined by homology are, in fact, more suitable objects of psychological – and particularly neuropsychological – investigation than categories defined by analogy. (shrink)

This contribution to the adaptationism debate elaborates the nature of constraints and their importance in evolutionary explanation and argues that the adaptationism debate should be limited to the issue of how to privilege causes in evolutionary explanation. I argue that adaptationist explanations are deeply conceptually dependent on developmental constraints, and explanations that appeal to constraints are dependant on the results of natural selection. I suggest these explanations should be integrated into the framework of historical causal explanation. Each strategy explicitly appeals (...) to some aspect of the evolutionary process, while implicitly appealing to others. Thus, adaptationists and anti-adaptationists can offer complementary causal explanations of the same explanandum. This eliminates much of the adaptationism debate and explains why its adversaries regularly agree with each other more than they would like. The adaptationism issue that remains is a species of the general issue of how to privilege causes in explanation. I show how a proposed solution to this general problem might be brought to bear on evolutionary explanations, and investigate some difficulties that might arise due to the nature of the evolutionary process. (shrink)

Editors' introduction to the special issue on homology (Biology and Philosophy Vol. 22, Issue 5, 2007).

A number of authors have pointed to “convergent evolution” as evidence for the central role of natural selection in shaping predictable trajectories of macroevolution. However, there are numerous conceptual and empirical difficulties that arise in broadly appealing to the frequency of homoplasy as evidence for a non-contingently constrained adaptational design space. Most important is the need to distinguish between convergent (externally constrained) and parallel (internally constrained) evolution, and to consider how the respective frequencies of these significantly different sources of homoplasy (...) affect a strong adaptationist view of life. In this paper, I critically evaluate Simon Conway Morris’s use of the homoplasy literature to support his argument for a non-contingent, counterfactually stable account of macroevolutionary pattern. In so doing, I offer a conception of parallelism which avoids the charge that it differs from convergence merely in degree and not in kind. I argue that although organisms sharing a homoplastic trait will also share varying degrees of homology, it is the underlying developmental homology with respect to the generators directly causally responsible for the homoplastic event that defines parallel evolution and non-arbitrarily distinguishes it from convergence. The notion of “screening-off” is used to distinguish the proximal generators of a homoplastic trait from its more distal genetic causes (such as a master control gene). (shrink)

Life's Solution builds a persuasive case for the predictability of evolutionary outcomes. The case rests on a remarkable compilation of examples of convergent evolution, in which two or more lineages have independently evolved similar structures and functions. The examples range from the aerodynamics of hovering moths and hummingbirds to the use of silk by spiders and some insects to capture prey. Going against the grain of Darwinian orthodoxy, this book is a must read for anyone grappling with the meaning of (...) evolution and our place in the Universe. Simon Conway Morris is the Ad Hominen Professor in the Earth Science Department at the University of Cambridge and a Fellow of St. John's College and the Royal Society. His research focuses on the study of constraints on evolution, and the historical processes that lead to the emergence of complexity, especially with respect to the construction of the major animal body parts in the Cambrian explosion. Previous books include The Crucible of Creation (Getty Center for Education in the Arts, 1999) and co-author of Solnhofen (Cambridge, 1990). Hb ISBN (2003) 0-521-82704-3. (shrink)

I adopt a cladistic view of species, and explore the possibility that there exists an equally valuable cladistic view of organismic traits. This suggestion seems to run counter to the stress on functional views of biological traits in recent work in philosophy and psychology. I show how the tension between these two views can be defused with a multilevel view of biological explanation. Despite the attractions of this compromise, I conclude that we must reject it, and adopt an essentially cladistic (...) conception of biological traits. (shrink)

In the wake of the paleobiological revolution of the 1970s and 1980s, paleontologists continue to investigate far-reaching questions about how evolution works. Many of those questions have a philosophical dimension. How is macroevolution related to evolutionary changes within populations? Is evolutionary history contingent? How much can we know about the causes of evolutionary trends? How do paleontologists read the patterns in the fossil record to learn about the underlying evolutionary processes? Derek Turner explores these and other questions, introducing the reader (...) to exciting recent work in the philosophy of paleontology and to theoretical issues including punctuated equilibria and species selection. He also critically examines some of the major accomplishments and arguments of paleontologists of the last 40 years. (shrink)