According to the Intelligent Design theory, some characteristics of the existing biological organisms would be fantastically improbable on the assumption that they are merely the product of natural selection. Therefore, it is concluded that the standard evolutionary theory is false and that Intelligent Design, as the only plausible alternative explanation, must be accepted. Most philosophers of science argue that this kind of probabilistic reasoning is logically fallacious because it tries to establish the truth of Intelligent Design without deriving any testable predictions from that theory itself. I try to show, however, that this particular methodological criticism is not convincing. In particular, I claim that there is no logical fallacy in the general idea underlying the main argument in favor of Intelligent Design (the argument from improbability) that observation O could in principle favor Intelligent Design (ID) over evolution (E), if O is extremely improbable given E, and despite the fact that the probability of O given ID is completely unknown. I very much doubt that such observation O would ever be found, but again this only shows that the argument from improbability has a false premise, not that it contains any fatal logical flaw.
In this paper, I will focus on and clarify some methodological and theoretical issues in cultural evolutionary theory. When we consider the evolutionary history of human behaviors, we cannot ignore culture. However the influence of culture on human evolution has been disregarded by some evolutionary psychologists and human behavioral ecologists. For example, one human behavioral ecologist goes as far as to claim that she "find[s] culture unnecessary". There are, on the other hand, some approaches that focus on and emphasize the influence of culture in human evolution: dual inheritance theory, memetics, epidemiology of culture (or representation), and so on. Among these approaches, we can see some methodological and theoretical controversies. First, dual inheritance theory advocated mainly by Rob Boyd and Pete Richerson, which is based on mathematical models with population thinking and some psychological biases (e.g., prestige and conformity biases), is now relatively prevailing, but some researchers have criticized this approach. For example, Dan Sperber has tried to construct an epidemiological model of cultural evolution relying on his relevance theory of communication. Moreover, although Boyd and Richerson have fiercely criticized massive modularity hypothesis (MMH), which evolutionary psychology has regarded as one of its main assumptions and also as incompatible with cultural evolutionary theory, Sperber, Clark Barrett and others argue that both are compatible: our minds are composed of many mental modules and such modules are not hardwired but gradually formed through developmental process. These differences and controversies are not only empirical but also conceptual. In examining these differences and controversies, therefore, I will give a philosophical analysis of them.
For the past quarter of the century, conceptual issues in evolutionary biology have been most lively debated by philosophers of biology. In this regard, evolution is a center of gravity in philosophy of biology. The most discussed topic in evolution concerns unit(s) and power of selection. Recently, evolutionary psychology has been emerging as a major topic of philosophy of biology: Is human mind an adaptation? Does the mind consist of a massive module? On such issues in architecture of mind, evolutionary psychology has been challenging a major view of cognitive science. Modularity of mind and adaptionism have been hot spots in the debates. More recently, developmental biology comes on the scene. On the role and status of genes in development, many philosophers of biology are competing with: developmental systems theory, selfish gene theory, and Evo Devo (an abbreviation of evolutionary developmental biology). Interestingly enough, both developmental systems theory and Evo Devo are demanding reinterpretation of traditional concepts of evolution and development. Especially, Evo Devo has a potential to shed light on the issues such as units of selection, adaptationism, and architecture of mind. Evo Devo modularity is the key to tackle these issues. In this talk, I'm going to deal with major issues in philosophy of biology in the light of Evo Devo modularity. Firstly, I discuss module concepts in biology and their recent usages in Evo Devo. This is used as conceptual resources for remaining discussion. Secondly, I apply Evo-Devo modularity to major issues in philosophy of biology. They can be divided into three: evolutionary changes, nature of selection, and architecture of mind. On nature of evolutionary changes, I suggest a new way of thinking about the very old controversies, such as gradualism vs. saltationism and evolution vs. progress, in the light of Evo Devo modularity. Then I take a modular approach to conceptual issues in selection. I review traditional views on units and levels of selection critically and suggest a new brand, so called 'modular selection theory'. Modular selection theory is a combination of a (diachronic) multi-level selection theory and a concept of 'modules as units'. I also take a modular approach to adaptationism and argue for a modular adaptationism, criticizing both atomistic adaptationism and holistic anti-adaptationism. Finally, I try to apply Evo-Devo modularity to mind modularity thesis, arguing against Fodor's perceptual modularity thesis. In brief, this talk is a modular approach to traditional major issues in philosophy of biology. This sketch can be coined as a 'modularism', which is to be studied further in depth.
In this talk, I will critically examine the logic of evolutionary psychology. Specifically, I will make the following cases as the ones which will count against the claims of evolutionary psychologists.
1) The reasoning pattern of evolutionary psychology, often called 'evolutionary functional analysis,' is typically justified by regarding it as an equivalent of 'hypothetico-deductive method', regularly acknowledged formula of sound scientific inference. But the mere fact that the reasoning pattern follows the same formula does not warrant its scientific legitimacy.
2) Gould adapted his charge of 'adaptationism' against sociobiology almost unchanged to his criticism of evolutionary psychology. Although there are some flaws in his argument --- for example, he did not properly understand the important discontinuities between sociobiology and evolutionary psychology --- we can still find some elements of truth in his accusation about the speculative character of the reasoning of evolutionary psychology.
3) Evolutionary functional analysis begins with identifying 'adaptive problems' (selective pressures) our ancestors had to face in the ecological environment in the Pleistocene epoch in which they were struggling to make a living as hunter-gatherers (often referred to as the Environment of Evolutionary Adaptedness: EEA). There are some unfounded speculations, however, in this reasoning step which makes evolutionary functional analysis deviate from hypothetico-deductive method.
4) Although the thesis of 'Ancient Origin of Our Mind' found in such authors as Cosmides, Tooby, or Pinker counts for its truth on the assumption of the stability of physico-ecological environments which our ancestors have inhabited since the end of the Pleistocene, this assumption loses its plausibility once we consider the highly likely possibility that the evolution of psychological adaptations is affected largely by the change of social environments mainly composed of other people in competition, not just by that of physico-ecological environments.