Model 1, the bundle of evolutionary conditions on which the ladder has rested to this point, is alarmingly simplistic. It is essentially a repository of all the simplifying assumptions that make for easy mathematical analysis of a population process. Among other restrictive features it does not allow for natural limitations on population size, nor does it take into account sexual reproduction.

In this chapter it will be seen that the latter two restrictions, at least, can be eased without changing the kind of logic produced. The analyses of how these constraints can be lifted are intended as case studies. They suggest that the biological foundations of the classical logic are not limited to Model 1, but can be made considerably more accommodating of realistic biological complexity. The evolutionary underpinning for the classical logic is a good deal broader than Model 1 alone might have made it appear.

TRAIT-NEUTRAL REGULATION

As noted by Darwin, a population growing unchecked at a constant proportional rate would soon run out of standing room. Exponential expansion simply cannot be kept up. It is important then, if realism is to be respected, that the effect of population-limiting contingencies be incorporated into the model somehow, and not ignored entirely as in Model 1.

The factors that constrain population growth are commonly called ‘regulatory’ conditions. Regulation will accordingly be used here as a cover term for all growth-limiting mechanisms. Regulation has to be taken into account in any process model that pretends to even rudimentary completeness over substantial evolutionary time periods.