Neo-teleology is the two part thesis that, e.g., (i) we have hearts because of what hearts are for: Hearts are for blood circulation, not the production of a pulse, so hearts are there--animals have them--because their function is to circulate the blood, and (ii) that (i) is explained by natural selection: traits spread through populations because of their functions. This paper attacks this popular doctrine. The presence of a biological trait or structure is not explained by appeal to its function. (...) To suppose otherwise is to trivialize natural selection. (shrink)

According to the received view of evolution, only genes are inherited. From this view it follows that only genetically-caused phenotypic variation is selectable and, thereby, that all selection is at bottom genetic selection. This paper argues that the received view is wrong. In many species, there are intergenerationally-stable phenotypic differences due to environmental differences. Natural selection can act on these nongenetically-caused phenotypic differences in the same way it acts on genetically-caused phenotypic differences. Some selection is at bottom nongenetic selection. The (...) argument against the received view involves a reformulation of the concepts of inheritance and heritability. Inherited factors are all those developmental factors responsible for parent–offspring similarity; some inherited factors are genetic and some are not. Heritable variation is intergenerationally-stable phenotypic variation; some such variation is genetically-caused and some is not. The received view and its critics The possibility of nongenetic selection (the lucky butterfly) The reality of nongenetic selection 3.1 Imprinting mechanisms 3.2 Other learning mechanisms 3.3 Other nongenetic mechanisms Genetic and nongenetic inheritance mechanisms Genetic and nongenetic inherited factors Genetic and nongenetic heritability Conclusions + Current address: Dr Matteo Mameli, Research Fellow, King's College, Cambridge, CB2 1ST, United Kingdom, matteo.mameli{at}kings.cam.ac.uk' + u + '@' + d + ''//-->. (shrink)

The ultimate source of explanation in biology is the principle of natural selection. Natural selection means differential reproduction of genes and gene combinations. It is a mechanistic process which accounts for the existence in living organisms of end-directed structures and processes. It is argued that teleological explanations in biology are not only acceptable but indeed indispensable. There are at least three categories of biological phenomena where teleological explanations are appropriate.

This paper describes an alternative to the common view that explanation in the special sciences involves subsumption under laws. According to this alternative, whether or not a generalization can be used to explain has to do with whether it is invariant rather than with whether it is lawful. A generalization is invariant if it is stable or robust in the sense that it would continue to hold under a relevant if it is stable or robust in the sense that it (...) would continue to hold under a relevant class of changes. Unlike lawfulness, invariance comes in degrees and has other features that are well suited to capture the characteristics of explanatory generalizations in the special sciences. For example, a generalization can be invariant even if it has exceptions or holds only over a limited spatio-temporal interval. The notion of invariance can be used to resolve a number of dilemmas that arise in standard treatments of explanatory generalizations in the special sciences. (shrink)

I distinguish two senses in which organisms are mechanically inexplicable for Kant. Mechanical inexplicability in the first sense is shared with artefacts, and consists in their exhibiting regularities irreducible to the regularities of matter. Mechanical inexplicability in the second sense is peculiar to organisms, consisting in the reciprocal causal dependence of an organism's parts. This distinction corresponds to two strands of thought in Aristotle, one supporting a teleological conception of organisms, the other supporting a conception of organisms as natural. Recognizing (...) this distinction helps us to see how a teleological conception of organisms is compatible with recent advances in biology. (shrink)