David Spurrett

Causal exclusion arguments, especially as championed by Kim, have recently made life uncomfortable for would-be non-reductive physicalists. Non-reductive physicalism was itself, in turn, partly a response to earlier arguments against reductionism. The philosophy of science, though, distinguishes more forms of reduction than philosophy of mind generally cares to. In this paper I review four major families of reductionist thesis, and give reasons for keeping them more carefully separate than usual. South African Journal of Philosophy Vol. 25(2) 2006: 159-171

Clark and Chalmers (1998) defend the hypothesis of an ‘Extended Mind’, maintaining that beliefs and other paradigmatic mental states can be implemented outside the central nervous system or body. Aspects of the problem of ‘language acquisition’ are considered in the light of the extended mind hypothesis. Rather than ‘language’ as typically understood, the object of study is something called ‘utterance-activity’, a term of art intended to refer to the full range of kinetic and prosodic features of the on-line behaviour of interacting humans. It is argued that utterance activity is plausibly regarded as jointly controlled by the embodied activity of interacting people, and that it contributes to the control of their behaviour. By means of specific examples it is suggested that this complex joint control facilitates easier learning of at least some features of language. This in turn suggests a striking form of the extended mind, in which infants’ cognitive powers are augmented by those of the people with whom they interact.

There has been lively recent debate over the value of appeals to intuitions in philosophy. Some, especially ‘experimental philosophers’, have argued that such appeals can carry little or no evidential weight, and that standard analytic philosophy is consequently methodologically bankrupt. Various defences of intuitions, and analytic philosophy, have also been offered. In this paper I review the case against intuitions, in particular the claims that intuitions vary with culture, and are built by natural selection, and argue that much of their force depends on assuming that the required sense of intuition is of a kind of human universal. In opposition to this view I argue that there is reason to regard intuitions of professional philosophers as parochial developmental achievements (so that cultural variation among non-professionals is irrelevant) and also the product of a training process that warrants ascribing some evidential weight to them. The argument made here is not anti-naturalistic, nor does it grant intuitions any special or trumping evidential status. Unlike some defences of analytic philosophy it does not depend on denying that philosophers appeal to intuitions at all

The present work is focussed on the completeness of physics, or what is here called the Completeness Thesis: the claim that the domain of the physical is causally closed. Two major questions are tackled: How best is the Completeness Thesis to be formulated? What can be said in defence of the Completeness Thesis? My principal conclusions are that the Completeness Thesis can be coherently formulated, and that the evidence in favour if it significantly outweighs that against it. In opposition to those who argue that formulation is impossible because no account of what is to count as physical can be provided, I argue that as long as the purpose of the argument in which the account is to be used are borne in mind there are no significant difficulties. The account of the physical which I develop holds as physical whatever is needed to fix the likelihood of pre-theoretically given physical effects, and hypothesises in addition that no chemical, biological or psychological factors will be needed in this way. The thus formulated Completeness Thesis is coherent, and has significant empirical content. In opposition to those who defend the doctrine of emergentism by means of philosophical arguments I contend that those arguments are flawed, setting up misleading dichotomies between needlessly attenuated alternatives and assuming the truth of what is to be proved. Against those who defend emergentism by appeal to the evidence, I argue that the history of science since the nineteenth century shows clearly that the empirical credentials of the view that the world is causally closed at the level of a small number of purely physical forces and types of energy is stronger than ever, and the credentials of emergentism correspondingly weaker. In opposition to those who argue that difficulties with reductionism point to the implausibility of the Completeness Thesis I argue that completeness in no way entails the kinds of reductionism which give rise to the difficulties in question. I argue further that the truth of the Completeness Thesis is in fact compatible with a great deal of taxonomic disorder and the impossibility of any general reduction of non-fundamental descriptions to fundamental ones. In opposition to those who argue that the epistemological credentials of fundamental physical laws are poor, and that those laws should in fact be seen as false, I contend that truth preserving accounts of fundamental laws can be developed. Developing such an account, I test it by considering cases of the composition of forces and causes, where what takes place is different to what is predicted by reference to any single law, and argue that viewing laws as tendencies allows their truth to be preserved, and sense to be made of both the experimental discovery of laws, and the fact that composition enables accurate prediction in at least some cases