Finally got started on Gould's `The Structure of Evolutionary Theory'. Below is a long excerpt that I think probably summarizes the entire thrust of the book. Pretty awesome stuff. On the other hand, I have no idea how this will strike biologists. Any other there want to comment?
Chuck Grimes --------------
``As the most striking general contrast that might be illuminated by reference to the different Zeitgeists of Darwin's time and our own, modern revisions for each essential postulate of Darwinian logic substituted mechanics based on interaction for Darwin's single locus of causality and directional flow of effects. Thus, for Darwin's near exclusivity of organismic selection, we now propose a hierarchical theory with selection acting simultaneously on a rising set of levels, each characterized by distinctive, but equally well-defined Darwinian individuals within a genealogical hierarchy of gene, cell-lineage, organism, deme, species, and clade. The results of evolution then emerge from complex, but eminently knowable, interactions among these potent levels, and do not simply flow out and up from a unique casual locus of organismal selection.
A similar substitution of interaction for directional flow then pervades the second branch of selection's efficacy, as Darwin's fundamentalist formulation---with unidirectional flow from an external environment to an isotropic organic substrate that supplies `random' raw material but imposes no directional vector of its own to `push back' from internal sources of constraint---yields to a truly interactive theory of balance between the functionalist Darwinian `outside' of natural selection generated by environmental pressures, and a formalist `inside' of strong, interesting and positive constraints generated by specific past histories and timeless structural principles. Finally, on the third and last branch of selection's range, the single and controlling micro-evolutionary locus of Darwinian causality yields to a multileveled model of tiers of time, with a unified set of processes working in distinctive and characteristic ways at each scale, from allelic substitution in observable years to catastrophic decimation of global biotas. Thus, and in summary, for the unifocal and non-interactive Darwinian models of exclusively organismal inside, and a microevolution-ary locus for mechanisms of change that smoothly extrapolate to all scales, we substitute a hierarchical selectionist theory of numerous interacting levels, a balanced and bidirectional flow of casuality between external selection and internal constraint (interaction of functionalist and structuralist perspectives), and causal interaction among tiers of time.
Among the many consequences of these interactionist reformulations, punctuational rather than continuationist models of change (with stronger structuralist components inevitably buttressing the punctuational versions) may emerge as the most prominent and most interesting. The Darwinian mechanics of functionalism yield an expectation of continuously improving local adaptation, with longterm stability representing the achievement of an optimum. But interactionist and multi-leveled models of causality competing forces at numerous levels, with change then regarded as exceptional rather than intrinsically ticking most of the time, and punctuational rather than smoothly continuous when it does occur (representing the relatively quick transition that often accompanies a rebalancing of forces).
To end this admittedly vague section with the punch of paradox (and even with a soundbite), I would simply note the almost delicious irony that the formulation of a hierarchical theory of selection---the central concept of this book, and invoking a non-vernacular meaning of hierarchy in the purely structural sense of rising levels of inclusivity---engenders, as its most important consequence, the destruction of a different and more familiar meaning of hierarchy: that is, the hierarchy of relative value and importance embodied in Darwin's privilaging of organismic selection as the ultimate source of evolutionary change at all scales. Thus, a structural and descriptive hierarchy of equally effective casual levels undermines a more conventional hierarchy of relative importance rooted in Darwin's exclusive emphasis on the micro-evolutionary mechanics of organismal selection. And so, this structuralist view of nature's order enriches the structure of evolutionary theory---carrying the difference between strict Darwinism and our current understanding through more than enough metatheoretical space to fashion a Falconerian, not merely a Darwinian, rebuilding and extension for our edifice of coherent explanation.'' (32-3p)