Elliott Sober

In Chapter 12 of Warrant and Proper Function, Alvin Plantinga constructs two arguments against evolutionary naturalism, which he construes as a conjunction E&N .The hypothesis E says that “human cognitive faculties arose by way of the mechanisms to which contemporary evolutionary thought directs our attention (p.220).”1 With respect to proposition N , Plantinga (p. 270) says “it isn’t easy to say precisely what naturalism is,” but then adds that “crucial to metaphysical naturalism, of course, is the view that there is no such person as the God of traditional theism.” Plantinga tries to cast doubt on the conjunction E&N in two ways.His “preliminary argument” aims to show that the conjunction is probably false, given the fact (R) that our psychological mechanisms for forming beliefs about the world are generally reliable.His “main argument” aims to show that the conjunction E&N is self-defeating — if you believe E&N , then you should stop believing that conjunction.Plantinga further develops the main argument in his unpublished paper “Naturalism Defeated” (Plantinga 1994).We will try to show that both arguments contain serious errors

We explore the evidential relationships that connect two standard claims of modern evolutionary biology. The hypothesis of common ancestry (which says that all organisms now on earth trace back to a single progenitor) and the hypothesis of natural selection (which says that natural selection has been an important influence on the traits exhibited by organisms) are logically independent; however, this leaves open whether testing one requires assumptions about the status of the other. Darwin noted that an extreme version of adaptationism would undercut the possibility of making inferences about common ancestry. Here we develop a converse claim—hypotheses that assert that natural selection has been an important influence on trait values are untestable unless supplemented by suitable background assumptions. The fact of common ancestry and a claim about quantitative genetics together suffice to render such hypotheses testable. Furthermore, we see no plausible alternative to these assumptions; we hypothesize that they are necessary as well as sufficient for adaptive hypotheses to be tested. This point has important implications for biological practice, since biologists standardly assume that adaptive hypotheses predict trait associations among tip species. Another consequence is that adaptive hypotheses cannot be confirmed or disconfirmed by a trait value that is universal within a single species, if that trait value deviates even slightly from the optimum. 1 Two Darwinian hypotheses 2 Logical independence 3 How adaptive hypotheses bear on the tree of life hypothesis 4 How the tree of life hypothesis bears on adaptive hypotheses 5 What do adaptive hypotheses predict? 6 Common ancestry and quantitative genetics to the rescue 7 Conclusion.

The substance of the commentaries, however, reveals considerable disagreement about how UO conceptualizes the idea of group selection. Dennett describes the issues as “mind-twistingly elusive and slippery” and hints that it is mere hype to say that group selection has been revived. Barrett and Godfrey-Smith discuss the problem of multiple perspectives at length and claim that we are too liberal in our definition of groups. We believe that these criticisms obscure the simplicity of the basic question that group selection theory is designed to answer and the historical continuity of that theory, from Darwin to the present.

Los filósofos han tendido a discutir el esencialismo como si fuera una doctrina global, una filosofía que, por alguna razón uniforme, debiera ser adoptada por todas las ciencias o por ninguna. Popper (1972) ha adoptado una postura global negativa, porque ve al esencialismo como un obstáculo fundamental para la racionalidad científica. También Quine (1953b, 1960), por una combinación de motivos semánticos y epistemológicos, quiere desterrar el esencialismo de la totalidad del discurso científico. Sin embargo, en fechas más recientes, Putnam (1975) y Kripke (1972) han propugnado doctrinas esencialistas y han afirmado que es tarea de cada ciencia investigar las propiedades esenciales de sus clases naturales constitutivas.

In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s but a positive literature began to grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as “replicators” which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be “vehicles” of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units.The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to “organs” of group-level “organisms.” Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals.