The thesis that natural selection explains the frequencies of traits in populations, but not why individual organisms have the traits tehy do, is here defended and elaborated. A general concept of ‘distributive explanation’ is discussed.

argue that natural selection does not explain the genotypic arid phenotypic properties of individuals. On this view, natural selection explains the adaptedness of individuals, not by explaining why the individuals that exist have the adaptations they do, but rather by explaining why the individuals that exist are the ones with those adaptations. This paper argues that this ‘Negative’ view of natural selection ignores the fact that natural selection is a cumulative selection process. So understood, it explains how the genetic sequences (...) that individuals inherit and that are responsible for their complex (and co-adapted) adaptations first arose in the gene-pool. (shrink)

The aim of this paper is to outline a typologyof selection processes, and show that differentsub-categories have different explanatorypower. The basis of this typology of selectionprocesses is argued to be the difference ofreplication processes involved in them. Inorder to show this, I argue that: 1.Replication is necessary for selection and 2.Different types of replication lead todifferent types of selection. Finally, it isargued that this typology is philosophicallysignificant, since it contrasts cases ofselection (on the basis of the replicationprocesses involved in them) (...) whereby selectioncauses adaptation – and, therefore, can beused in explanations of the (real or apparent)teleology of Nature – and cases in whichselection lacks such explanatory power. (shrink)

Here is a dilemma concerning the history of science. Can the history of scientific thought be reduced to the history of the beliefs, motives and actions of scientists? Or should we think of the history of scientific thought as in some sense independent from the history of scientists? The aim of this paper is to carve out an intermediate position between these two. I will argue that the history of scientific thought supervenes on, but not reducible to, the history of (...) scientists. There is a legitimate level of description for analyzing the history of scientific thought that does not reduce to the individual level of scientists. Yet, every aspect of the history of scientific thought is determined by the actual motives and actions of individual scientists. Maybe surprisingly, I use Imre Lakatos’s controversial concept of the rational reconstruction of the history of science in order to argue for this intermediate position. (shrink)

One of the most deeply entrenched ideas in Popper's philosophy is the analogy between the growth of scientific knowledge and the Darwinian mechanism of natural selection. Popper gave his first exposition of these ideas very early on. In a letter to Donald Campbell, 1 Popper says that the idea goes back at least to the early thirties. 2 And he had a fairly detailed account of it in his "What is dialectic?", a talk given in 1937 and published in 1940: (...) 3 If we want to explain why human thought tends to try out every conceivable solution for any problem with which it is faced, then we can appeal to a highly general sort of regularity. The method by which a solution is approached is .. (shrink)

Two strong arguments have been given in favor of the claim that no selection process can play a role in explaining adaptations. According to the first argument, selection is a negative force; it may explain why the eliminated individuals are eliminated, but it does not explain why the ones that survived (or their offspring) have the traits they have. The second argument points out that the explanandum and the explanans are phenomena at different levels: selection is a population-level phenomenon, whereas (...) adaptation occurs on the individual level. Thus, selection can explain why individuals in a certain population have a certain trait, but it cannot explain why a certain indi- vidual has this trait. After pointing out that both arguments ignore the significance of the limitation of environmental resources, I will construe a positive argument for the claim that cumulative selection processes can, indeed, play a role in explaining adaptations. (shrink)

Instead of using only one notion of selection I argue for a broader typology of different types of selection. Three such types are differentiated, namely simple one-step selection, iterated one-step selection, and multi-step selection. It is argued that this more general and more inclusive typology might face more effectively the possible challenges of a general account of selection.

The concept of "fitness" is a notion of central importance to evolutionary theory. Yet the interpretation of this concept and its role in explanations of evolutionary phenomena have remained obscure. We provide a propensity interpretation of fitness, which we argue captures the intended reference of this term as it is used by evolutionary theorists. Using the propensity interpretation of fitness, we provide a Hempelian reconstruction of explanations of evolutionary phenomena, and we show why charges of circularity which have been levelled (...) against explanations in evolutionary theory are mistaken. Finally, we provide a definition of natural selection which follows from the propensity interpretation of fitness, and which handles all the types of selection discussed by biologists, thus improving on extant definitions. (shrink)

The article discusses Karl Popper’s account of Lamarckism. In this article I use Popper’s published and unpublished statements regarding Lamarckism as well as his correspondence with the Australian immunologist Edward Steele and other biologists to examine why Popper was interested in Lamarckism, how his account of Lamarckism can be understood in the context of his philosophy, and what, if any, new context Popper provided for the discussion of this abandoned doctrine. I begin by discussing Popper’s frame of reference regarding Lamarckism, (...) examining how it changed following his involvement with different “transitory groups” of biologists concerned with redefining the boundaries between traditional disciplines. I then discuss Popper’s account of Lamarckism in positioning it in relation to three aspects of his philosophy: his distinction between the principles of induction/instruction and deduction/selection, his distinction between scientific and teleological concepts, and his concept of progress in science. Then, I follow the debate concerning Steele’s Lamarckian experiments with a closer look at Popper’s role and his position in this controversy. I conclude that Popper’s writings provided a new context for the discussion of Lamarckism in the 1970s and 1980s, thus making it “scientifically acceptable” again. I preface this discussion by a brief outline of Steele’s Lamarckian hypothesis and Popper’s comments on Steele’s work. (shrink)