What is an "evolutionary perspective?"

Proponents of evolutionary studies (EvoS) claim that an evolutionary perspective makes it possible to make sense of a broad range of different disciplines.  In fact, in more private moments I've heard claims that disciplines outside the hard sciences are primarily atheoretical and that the lack of a unifying framework has hindered their progress.  Instead, the thinking goes, these different scholarly traditions lumber along with each generation doing nothing more than finding clever ways of discrediting the generation before, with no lasting body of theoretical or empirical work to build from.

Naturally, EvoS advocates claim that evolution can save the day.  Taking an evolutionary perspective, they propose, makes it possible to unite vastly disparate scholarly traditions and to make sense of an otherwise chaotic intellectual landscape.  At first blush, this seems plausible, perhaps even compelling.  Or at least it does if you're trained in the life sciences where evolutionary theory does important work.  As Dobzhanzsky is so often quoted as saying, "Nothing in biology makes sense except in light of evolution," so how could taking an evolutionary perspective not shed light on all the other things that life has managed to create? 

Underneath all this enthusiasm, however, is one rather glaring problem.  Namely, what does it mean to take an evolutionary perspective?  For that matter, what is an evolutionary perspective in the first place?  In all the years I've been associated with EvoS I can’t recall anyone ever articulating exactly what they mean by this and I'm coming to find that rather deeply troubling and problematic.  Underneath it all is an implication that evolutionary theory is a single thing, a unified set of principles by which life can be understood.  With a bit of training in how to use the "evolutionary toolkit," the story goes, all of life's mysteries can be revealed and that holds as true for culture, economics, psychology, literature, etc. as it does for biology. 

As someone trained in evolution, though, I have to ask just what is this toolkit we’re all supposed to have?  Is it simply Darwin's recipe of mixing inheritance, variation and selection?  Is that the simple logic that scholars should rally around?  In biology, the answer would seem to be a rather resounding no and it has been since the Modern Synthesis.  At the very least, then, taking an evolutionary perspective should include things like Mendelian inheritance, mutation and population genetics.  However, we can’t stop there.  As the Extended Synthesis is demonstrating, no evolutionary toolkit would be complete without also including topics such as evo-devo, phenotypic plasticity, multilevel selection, epigenetics, niche construction, robustness and evolvability.  In seeking conscilience, though, we’re trying to explain human behavior, too, so what are we to make of culture?  Cultural evolution is an obvious answer, but this hardly represents a unified perspective.  While not necessary at odds with one another, gene culture coevolution is nevertheless a fundamentally different discipline than evolutionary psychology, which is itself hardly a single theoretical framework, and these both offer very different approaches, methodologies and preoccupations than human sociobiology, behavioral ecology and memetics.

As best I can tell, then, there is no single evolutionary perspective, no single evolutionary toolkit.  Rather, the study of evolution has led to a rather dizzying array of specialized disciplines, each asking different kinds of questions about different kinds of phenomena.  Sure, there are varying degrees of overlap between many of these fields.  However, I doubt that many specialists in, say, niche construction, would be so bold as to claim expertise in evolutionary psychology simply because both fields can trace lines of intellectual thought back to Darwin.  Yet I have heard similarly bold claims, both publicly and in private, about what EvoS can bring to nearly every intellectual tradition imaginable.  If "applying an evolutionary perspective" is nothing more than arguing by analogy from biological principles, then to a limited extent I suppose this is true.  However, I can hardly blame those who have been trained in rich intellectual traditions with deep histories outside the Darwinian aegis if they find the application of biological analogies less than compelling or far from illuminating.

All that said, I remain cautiously enthusiastic about EvoS.  As a program it does have the capability to facilitate dialog between disciplines and to foster unique interdisciplinary research programs.  However, until we’re able to articulate a consensus about what this "evolutionary perspective" is that we all seem to take for granted, the ability of EvoS to bring about any kind of conscilience will remain a distant and rather fanciful dream.