Wim J. van der Steen

The nature of evolutionary theory: The semantic challenge

Philosophy of science should have a visible function in the assessment of scientific theories. Classically, theories were viewed as syntactic structures tied indirectly, through correspondence rules, to the realm of phenomena. This conception came to be known as the Received View. Today, heavily under attack, this view occurs in a confusing array of philosophical writings. Meanwhile the so-called Semantic View is offered as a worthy alternative. It introduces semantic interpretations right from the start, and thus seems to leave more room for pluralism within domains of science. Proponents of this view have recently introduced it into the realm of evolutionary biology. Some of them have argued that the Semantic View is more faithful to science as it appears in practice and that it has the power of accomodating biology as a non-general science. The present paper aims at showing that this defence of the Semantic View falls short of making it the best candidate for philosophical analysis of biological theories. Extant philosophical views (syntactic or semantic) of scientific theories are so complex that they can hardly be helpful for the practice of science. A simpler approach is indicated.

Towards disciplinary disintegration in biology

Interdisciplinary integration has fundamental limitations. This is not sufficiently realized in science and in philosophy. Concerning scientific theories there are many examples of pseudo-integration which should be unmasked by elementary philosophical analysis. For example, allegedly over-arching theories of stress which are meant to unite biology and psychology, upon analysis, turn out to represent terminological rather than substantive unity. They should be replaced by more specific, local theories. Theories of animal orientation, likewise, have been formulated in unduly general terms. A natural history approach is more suitable for the study of animal orientation. The tendency to formulate overgeneral theories is also present in evolutionary biology. Philosophy of biology can only deal with these matters if it takes a normative turn. Undue emphasis on interdisciplinary integration is a modern variant of the old unity of science ideal. The replacement of the ideal by a better one is an important challenge for the philosophy of science.

Interdisciplinary integration in biology? An overview

Philosophical theories about reduction and integration in science are at variance with what is happenign in science. A realistic approach to science show that possibilities for reduction and integration are limited. The classical ideal of a unified science has since long been rejected in philosophy. But the current emphasis on interdisciplinary integration in philosophy and in science shows that it survives in a different guise. It is necessary to redress the balance, specifically in biology. Methodological analysis shows that many of the grand interdisciplinary theories involving biology actually represent pseudo-integration covered up by inappropriate, overgeneral concepts. Integrationism is not bad, but it must be kept within reasonable bounds. If the present analysis is appropriate, there will have to be fundamental changes in research strategy both in science and in the philosophy of science.

Methodological problems in evolutionary biology IV. Stress and stress tolerance, an excercise in definitions

Grime (1979) in a recently developed theory distinguished three basic plant strategies: stress tolerance,ruderality and competition. He relates them to environments characterized in terms of stress and disturbance. Classifications of strategies and environments both are ultimately defined in terms of production. This tends to make the theory tautological. If the theory is to make sense, environments had better be defined in independent terms.

Methodological problems in evolutionary biology II. Appraisal of arguments against adaptationism

Methodological analysis shows that the concepts of fitness and adaptation are more complex than the literature suggests. Various arguments against ‘adaptationism’ are inadequate since they are couched in terms of unduly simplistic notions.

Methodological problems in evolutionary biology I. Testability and tautologies

The impact of philosophy of science on biology is slight. Evolutionary biology, however, is nowadays an exception. The status of the neo-Darwinian (synthetic) theory of evolution is seriously challenged from a methodological perspective. However, the methodology used in the relevant discussions is plainly defective. A correct application of methodology to evolutionary theory leads to the following conclusions. (a) The theory of natural selection (the core of neo-Darwinism) is unfalsifiable in a strict sense of the term. This, however, does not militate against the theory, because no scientific theory whatever is testable in this way. Under a more liberal testability criterion, the theory is surely testable. None the less, certain (not all) research programs may tend to make the theory untestable in practice. (b) It has often been argued that the tautologous character of the principle of natural selection, allegedly the focus of evolutionary theory, makes the theory untestable through circular reasoning. Actually, the principle is only a tautology if ‘fitness’ is wrongly defined in terms of actual survival. But even then circular reasoning need not ensue. (c) Evolutionary principles do not permit, without additional information, the derivation of statements about evolutionary events concerning particular species or populations. If this were a reason to criticize the theory (as has been argued in the literature), any other scientific theory would be inadequate by the same token.

Methodological problems in evolutionary biology: IX. The testability of optimal foraging theory

One of the major criticisms of optimal foraging theory (OFT) is that it is not testable. In discussions of this criticism opposing parties have confused methodological concepts and used meaningless biological concepts. In this paper we discuss such misunderstandings and show that OFr has an empirically testable, and even well-confirmed, general core theory. One of our main conclusions is that specific model testing should not be aimed at ‘proving’ optimality, but rather at identifying the context in which certain types of behaviour are optimal. To do this, it is necessary to be aware of the assumptions made in testing a model. The assumptions that are explicitly stated in the literature up to now do not completely cover the actual assumptions made in testing OFT models in practice. We present a more comprehensive set of assumptions. Although all the assumptions play a role in testing models, they are not of equal status. Crucial assumptions concern constraints and the relation between fitness and currency. Therefore, it is essential to make such assumptions testable in practice. We show that a more explicit relationship between OFT modelling and evolutionary theory can help with this. Specifically, phylogeny reconstruction and population dynamic modelling can and should be used to formulate assumptions concerning constraints and currencies.

Sociobiology in perspective

The branch of biology nowadays called “sociobiology” is often presented as a grand synthesis. If it is a synthesis at all, it is a very biased one. Firstly, it accentuates ultimate explanations in terms of evolution in such a way that the relevance of proximate explanations is obscured. Secondly, it has uncritically assimilated theories about evolution which are now widely disputed both for factual and for methodological reasons. Current disputes about the possible implications of sociobiology for social science are mostly off the mark. An evaluation of the biological theories involved should precede both attempts to amalgamate and attempts to separate biology and the social sciences.

The issue of generality in ethics

ConclusionDoes ethics have adequate general theories? Our analysis shows that this question does not have a straightforward answer since the key terms are ambiguous. So we should not concentrate on the answer but on the question itself. “Ethics” stands for many things, but we let that pass. “Adequate” may refer to varied arrays of methodological principles which are seldom fully articulated in ethics. “General” is a notion with at least three meanings. Different kinds of generality may be at cross-purposes, so we must not expect theories to be general in sundry senses. “Theory,” for that matter, is itself ambiguous. Some thinkers say that ethics cannot have theories, while others deny it. We doubt whether opposing parties are talking about the same things.No wonder, then, that controversies in ethics are long-lasting and unproductive. We hope that the methodology we have presented will alleviate some of them. The examples we chose show that this is feasible. Views such as Hares and Jonsen and Toulmins which are seemingly wide apart, show convergence if we put them in a methodological perspective.Our analysis also suggests that many alleged differences between science and ethics could fade away if methodology is brought to bear on them. Specifically, the idea that ethics compares poorly with science in view of limited generality, or poor means of justification, is unfounded. Those who defend this view over-rate the powers of science.

Methodological problems in evolutionary biology VII. The species plague

Various philosophers and evolutionary biologists have recently defended the thesis that species are individuals rather than sets. A decade of debates, however, did not suffice to settle the matter. Conceptual analysis shows that many of the key terms involved (“individuation”, “evolutionary species”, “spatiotemporal restrictedness”, “individual”) are ambiguous. Current disagreements should dissolve once this is recognized. Explication of the concepts involved leads to new programs for philosophical research. It could also help biology by showing how extant controversies concerning evolution may have conceptual rather than factual roots.