Re: gould on dawkins

[Jim Farmelant <farmelantj@xxxxxxxxxxxx>]

Both the gene-centric view of Darwinism posited by Dawkins, the late
William
Hamilton, George Williams & John Maynard Smith and the punctuated
equilibrium view of Darwinism posited by Gould & Eldredge constituted
challenges to the traditional Darwinism that had prevailed up to the
1960s which generally assumed that the individual organism was
the main unit of selection.  The gene-centered view began with
Hamilton's attempts to understand the evolutionary bases for
altruism which seemed to constitute a paradox if viewed in Darwinian
terms.  An organism that was inclined to sacrifice its interests for
the sake of others would seem to less fit from a Darwinian standpoint
since it would be less likely to survive long enough to reproduce.
Hamilton reasoned that this paradox could be resolved if we look at
things from the standpoint of the genes involved.  If we took genes
rather than organisms as the units of selection, then altruism might
well turn out to be a successful Darwinian strategy providing that for
instance altruistic organisms were inclined to act in the interests of
genetically related organisms (the famous kin-selection hypothesis).
The  greater risks that altruistic organisms bear for their altruism
may be more than compensated by the fact that the beneficiaries
being genetically related organisms will thus share many of the same
genes with their benefactors, hence altruism in such cases will
in fact increase the Darwinian fitness of those genes.

The biologist George Williams took up Hamilton's interpretation
of Darwinism and used Hamilton's' arguments to attack the
notion of group selection which was then enjoying currency among
some evolutionary biologists.  Williams' attacks were seen as so
persuasive that for a long time it was unrespectable for an evolutionary
biologist to advocate group selection in public (it has however, begun
to enjoy at least a partial rehabilitation in recent years).  John
Maynard
Smith a former electrical engineer and Marxist turned biologist
used game theory to further elaborate the gene-centric approach to
Darwinism while Richard Dawkins in a series of books starting with
*The Selfish Gene* popularized this way of understanding Darwinism
both among fellow scientists and the general educated public.

Stephen Jay Gould & Niles Eldredge agreed with Hamilton, Williams et al.
concerning the inadequacies of traditional understandings of Darwinism
but they proposed a different tack.  They suggested among other things
that
there might be a  whole hierarchy of units of selection: including genes
(as
Hamilton et al. had suggested), individual organisms, and species.  In
other words they posited that natural selection operates at the level of
genes,
of organisms and species.  They also argued that evolutionary history is
full of instances where natural selection operating at one level came
into
contradiction with the way natural selection was operating at a different
label.  Such contradictions between these different levels were it was
argued behind were among the forces behind what they perceived as
the tendency for evolution to proceed in discrete jumps.

Jim F.

On Tue, 25 Jul 2000 14:20:27 -0400 (EDT) Les Schaffer
<godzilla@xxxxxxxxxx> writes:
> there has been some brief discussion recently of the views on
> evolution of Richard Dawkins.
>
> While doing a little on-line reading this afternoon, i stumbled
> across
> an interesting article by Stephen J Gould and Elisabeth A. Lloyd
> entitled: Individuality and adaptation across levels of selection:
> How
> shall we name and generalize the unit of Darwinism?
>
> in particular, gould and lloyd speak of a disctinction between
> replicators (Dawkins) and interactors (Hull and others):
>
> <<<<< The central and contentious issue of causal agency in natural
> selection -- does Darwin's process work on organisms (as Darwin
> argued), on genes (as various reductionist accounts maintain), on
> supraorganismal units, or on some or all of these legitimate
> biological individuals simultaneously (as we and many others now
> hold)
> -- has generated much confusion, arising not so much from dispute
> about empirical matters, but from conceptual problems about the
> nature, locus, and meaning of causality in Darwin's mechanism. In
> particular, many biologists have mistakenly equated the need for
> keeping a ledger of evolutionary changes through time with the task
> of
> identifying causal agents of change -- a conflation of bookkeeping
> with causality.
>
> David Hull's important distinction between replicators and
> interactors
> (27) helped to clarify conceptual and empirical issues at the center
> of debates about units of selection. Hull modified Dawkins' concept
> of
> a replicator to designate any entity that can serve as a basis for
> copying itself. Hull's concept of interactor denotes an entity that
> interacts directly, as a cohesive whole, with its environment in
> such
> a way that replication becomes differential. For Hull, natural
> selection then becomes "a process in which the differential
> extinction
> and proliferation of interactors cause the differential perpetuation
> of the replicators that produced them" (ref. 27, p. 318; cf. ref.
> 11,
> pp. 317-318).
> >>>>
>
> abstract below, but the full article in HTML can be found online at:
>
>
http://www.pnas.org/cgi/content/full/96/21/11904?gca=96%2F21%2F11701&gca=
96%2F21%2F11904&gca=96%2F21%2F12198&sendit=Get+All+Checked+Abstract%28s%2
9&
>
> dat's a long link! if you have trouble navigating it, let me
> know. also, a pdf version can be downloaded directly at:
>
> http://www.pnas.org/cgi/reprint/96/21/11904.pdf
>
> les schaffer
>
> -----------------------------------------------
>
> Vol. 96, Issue 21, 11904-11909, October 12, 1999
>
> Evolution
>
> Individuality and adaptation across levels of selection: How shall
> we
> name and generalize the unit of Darwinism?
>
> Stephen Jay Gould*, and Elisabeth A. Lloyd
>
> * Museum of Comparative Zoology, Harvard University, 26 Oxford
> Street,
> Cambridge, MA 02138; and History and Philosophy of Science, Indiana
> University, 130 Goodbody Hall, Bloomington, IN 47405
>
> Contributed by Stephen Jay Gould, June 2, 1999
>
>         Abstract
>
> Two major clarifications have greatly abetted the understanding and
> fruitful expansion of the theory of natural selection in recent
> years:
> the acknowledgment that interactors, not replicators, constitute the
> causal unit of selection; and the recognition that interactors are
> Darwinian individuals, and that such individuals exist with potency
> at
> several levels of organization (genes, organisms, demes, and species
> in particular), thus engendering a rich hierarchical theory of
> selection in contrast with Darwin's own emphasis on the organismic
> level. But a piece of the argument has been missing, and individuals
> at levels distinct from organisms have been denied potency (although
> granted existence within the undeniable logic of the theory),
> because
> they do not achieve individuality with the same devices used by
> organisms and therefore seem weak by comparison.  We show here that
> different features define Darwinian individuality across scales of
> size and time. In particular, species-individuals may develop few
> emergent features as direct adaptations. The interactor approach
> works
> with emergent fitnesses, not with emergent features; and species, as
> a
> consequence of their different mechanism for achieving individuality
> (reproductive exclusivity among subparts, that is, among organisms),
> express many effects from other levels. Organisms, by contrast,
> suppress upwardly cascading effects, because the organismic style of
> individuality (by functional integration of subparts) does not
> permit
> much competition or differential reproduction of parts from
> within. Species do not suppress the operation of lower levels; such
> effects therefore become available as exaptations conferring
> emergent
> fitness a primary source of the different strength that species
> achieve as effective Darwinian individuals in evolution.

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