The Critical Rationalist                       Vol. 01  No. 04
ISSN: 1393-3809                                    31-Dec-1996


next 4.4 Variation
previous 4.2 Inheritance
contents

4.3 Selection

(28) Organism populations belonging to distinct, inheritance-based, S-lineages can interact in a manner giving rise to a quasi-deterministic selection dynamics. That is, an S-lineage population can consistently grow, at the expense of one or more other S-lineage populations, eventually displacing the latter completely. An S-lineage can thus be spontaneously and naturally selected over one or more other lineages. I shall call this a (natural) selection process.

(29) Of course, lineages in general, and S-lineages in particular, may participate in a very wide range of diverse ecological processes, most of which do not involve the quasi-deterministic elimination of one or more or them. Selection processes are, in this sense, only one special case of a much more general phenomenon. Nonetheless, selection processes play a peculiarly important role in the Darwinian explanatory schema, and must therefore be clearly separated out from all other possible ecological interactions.

(30) Note carefully that the conditions under which such a selection process will arise are highly variable, and difficult to characterise in general. Note, in particular, that not all lineages--not even all S-lineages --will necessarily be capable of participating in such a selection process; and whether such a process arises will depend both on the specific S-lineages present, and the extra-organismic ("environmental") situation.

(31) It is worth noting in passing here that the observation that the entities which get selected in Organismic Darwinism selection are a special kind of lineage (as opposed to individual organisms) is a major insight that was only fully or properly recognised within the last 40 years. Dawkins (1989, p. ix) provides a brief review of the genesis of this insight. It was originally formulated as the theory of "kin selection", but has been more recently popularised by Dawkins under the banner of the "selfish gene".[4]

(32) In circumstances where a selection process will occur it is generally possible to identify a numerical parameter, which can, in principle, be independently evaluated for each S-lineage involved, such that the relative values of this parameter are predictive of the ultimate outcome of selection (and, indeed, of the rate at which the selective displacement will proceed). The parameter will typically be a function of expected fecundity and mortality in the given conditions.

(33) This numerical parameter is commonly referred to as fitness; however, like "adaptation", "fitness" is a term which has had a variety of ambiguous and conflicting meanings in the Darwinian literature, so, for the moment at least, I would prefer to avoid it. Instead I shall adopt the relatively neutral term selective-value, or S-value.[5]

(34) Note that S-value is not a property of an S-lineage as such: it is a property of an S-lineage relative to a particular selection process--that is, relative to a particular set of other S-lineages, with which it would interact, and relative to a particular set of common environmental conditions. The same S-lineage could be characterised by utterly different S-values relative to different selection processes; and S-value would be literally undefined on sets of S-lineages which do not collectively generate selection processes.[6] The common metaphor of Darwinian evolution as a process of hill-climbing on a "fitness landscape" is thus, at best, a highly dubious one.



next 4.4 Variation
previous 4.2 Inheritance
contents

The Critical Rationalist                       Vol. 01  No. 04
ISSN: 1393-3809                                    31-Dec-1996


Copyright © 1996 All Rights Reserved.
TCR Issue Timestamp: Tue Dec 31 17:37:08 GMT 1996

tcr-editors@www.eeng.dcu.ie