No abstract

We distinguish dynamical and statistical interpretations of evolutionary theory. We argue that only the statistical interpretation preserves the presumed relation between natural selection and drift. On these grounds we claim that the dynamical conception of evolutionary theory as a theory of forces is mistaken. Selection and drift are not forces. Nor do selection and drift explanations appeal to the (sub-population-level) causes of population level change. Instead they explain by appeal to the statistical structure of populations. We briefly discuss the implications of the statistical interpretation of selection for various debates within the philosophy of biology—the ‘explananda of selection’ debate and the ‘units of selection’ debate.

The central point of this essay is to demonstrate the incommensurability of 'Darwinian fitness' with the numeric values associated with reproductive rates used in population genetics. While sometimes both are called 'fitness', they are distinct concepts coming from distinct explanatory schemes. Further, we try to outline a possible answer to the following question: from the natural properties of organisms and a knowledge of their environment, can we construct an algorithm for a particular kind of organismic lifehistory pattern that itself will allow us to predict whether a type in the population will increase or decrease relative to other types? 1 Introduction 2 Darwinian fitness 3 Reproductive fitness and genetical models of evolution 4 The models of reproductive fitness 4.1 The Standard Viability Model 4.2 Frequency-dependent selection 4.3 Fertility models 4.4 Overlapping generations 5 Fitness as outcome 5.1 Fitness as actual increase in type 5.2 Fitness as expected increase in type 5.2.1 Expected increase within a generation 5.2.2 Expected increase between generations 5.2.3 Postponed reproductive fitness effects 6 The book-keeping problem 7 Conclusion We would like to thank

No abstract

We have argued elsewhere that natural selection is not a cause of evolution, and that a resolution-of-forces (or vector addition) model does not provide us with a proper understanding of how natural selection combines with other evolutionary influences. These propositions have come in for criticism recently, and here we clarify and defend them. We do so within the broad framework of our own 'hierarchical realization model' of how evolutionary influences combine.

Over the past fifteen years there has been a considerable amount of debate concerning what theoretical population dynamic models tell us about the nature of natural selection and drift. On the causal interpretation, these models describe the causes of population change. On the statistical interpretation, the models of population dynamics models specify statistical parameters that explain, predict, and quantify changes in population structure, without identifying the causes of those changes. Selection and drift are part of a statistical description of population change; they are not discrete, apportionable causes. Our objective here is to provide a definitive statement of the statistical position, so as to allay some confusions in the current literature. We outline four commitments that are central to statisticalism. They are: 1. Natural Selection is a higher order effect; 2. Trait fitness is primitive; 3. Modern Synthesis (MS)-models are substrate neutral; 4. MS-selection and drift are model-relative.

There are two general approaches to characterising biological functions. One originates with Cummins. According to this approach, the function of a part of a system is just its causal contribution to some specified activity of the system. Call this the ‘C-function’ (or ‘Cummins function’) concept. The other approach ties the function of a trait to some aspect of its evolutionary significance. Call this the ‘E-function’ (or ‘evolutionary function’) concept. According to the latter view, a trait's function is determined by the forces of natural selection. The C-function and E-function concepts are clearly quite different, but there is an important relation between them which heretofore has gone unnoticed. The purpose of this paper is to outline that relation.This is not the first paper to discuss the relation of C-function and E-function. Previous attempts all follow either one of two strategies. The first proposes that the two concepts are ‘unified.’ The other proposes that they are radically distinct and apply to wholly different fields within biology.

Cognitive scientists often employ the notion of innateness without defining it. The issue is, how is innateness defined in biology? Some critics contend that innateness is not a legitimate concept in biology. In this paper I will argue that it is. However, neither the concept of high heritability nor the concept of flat norm of reaction (two popular accounts in the biology literature) define innateness. An adequate account is found in developmental biology. I propose that innateness is best defined in terms of C. H. Waddington's concept of canalization.