The Critical Rationalist Vol. 01 No. 04 ISSN: 1393-3809 31-Dec-1996
(51) To analyse the arguments effectively, it is first necessary to distinguish two quite separate notions of "survival":
(52) I-survival obviously does not refer to survival in any absolute sense: individual organisms are essentially mortal, and have a finite lifetime--it is hardly meaningful to speak of individual organisms "surviving" without qualification.^{[8]} However, some organisms do survive longer relative to others. More generally, there is potentially a valid notion of "mean I-survival"--i.e. that a certain "kind" of organism may, in given conditions, show a consistent distribution of values for I-survival. Furthermore, if (and only if) there exist heritable characteristic(s) distinguishing such different "kinds" then they can serve to differentiate S-lineages. In that case coherent S-lineages, exhibiting distinctive (statistical) distributions of I-survival, can be formed. This distribution of I-survival would be a characteristic of an S-lineage. In fact, (mean) I-survival can then be thought of as a crude or partial measure of S-value (crude because the latter depends, at least, on fecundity as well as mortality); in particular it will generally be true that the greater the value of (mean) I-survival then the greater the S-value of the corresponding S-lineage.
(53) I emphasize that (mean) I-survival (as with S-value proper) is defined as an objective characteristic of an S-lineage in given conditions, which can (in principle) be evaluated independently of any prior knowledge of the outcome of any associated selection process.
(54) L-survival does (potentially) refer to "absolute" survival--in the sense that organism lineages can (apparently) survive indefinitely long.
(55) L-survival may also be related to S-value, but not in the relatively direct way which holds for I-survival. Let us suppose that, for independent reasons, we believe that two S-lineages will give rise to a selection process in specified conditions. Then we can infer that whichever S-lineage is the eventual L-survivor must have the greater value of S-value. Note carefully that this inference is valid if and only if we already know that we are dealing with a selection process.
(56) It should be clear that I-survival and L-survival are not the same thing. While they may be related this relationship is a contingent one; it would not hold if, for example, among the organisms being studied, there were no inheritable characteristics which were well correlated with I-survival; or if the S-lineages distinguished by different values of (mean) I-survival were not actually in competition with each other etc.
The Critical Rationalist Vol. 01 No. 04 ISSN: 1393-3809 31-Dec-1996
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TCR Issue Timestamp: Tue Dec 31 17:37:08 GMT 1996