Online research in philosophy

John Bickle's Psychoneural reduction: the new wave (Cambridge, MA: MIT Press, 1998) aims to resurrect reductionism within philosophy of mind. He develops a new model of scientific reduction, geared to enhancing our understanding of how theories in neuroscience and cognitive science are interrelated. I put this discussion in context, and assess the prospects for new wave reductionism, both as a general model of scientific reduction and as an attempt to defend reductionism in the philosophy of mind.

This version of this paper has been superseded by a substantially revised version in G. Strawson, Real Materialism and Other Essays (OUP 2008).

Reductionism in the Philosophy of Science develops a novel account of reduction in science and applies it to the relationship between classical and molecular genetics. However, rather than addressing the epistemological issues that have been essential to the reductionism debate in philosophy of biology, the discussion primarily pursues ontological questions, as they are known, about reducing the mental to the physical. For Sachse construes reductionism as a purely philosophical endeavor and defends the possibility of reduction in principle, which may not be relevant to understanding reductionist reasoning and explanation occurring in scientific practice, as discussed by philosophers of science. Likewise, the conceptual framework used stems more from metaphysics and philosophy of mind than philosophy of science. Sachse's aim is twofold. First, he argues for the special sciences' being reducible to physics, by deriving the in principle possibility of epistemological reduction from ontological reduction. Second, he attempts to simultaneously make room for the legitimacy of the special sciences, effecting a conservative reduction rather than an elimination of the special sciences.

Bickle argues for both a narrow causal reductionism, and a broader ontological-explanatory reductionism. The former is more successful than the latter. I argue that the central and unsolved problem in Bickle's approach to reductionism involves the nature of psychological terms. Investigating why the broader reductionism fails indicates ways in which phenomenology remains more than a handmaiden of neuroscience.

A classification of models of reduction into three categories — theory reductionism, explanatory reductionism, and constitutive reductionism — is presented. It is shown that this classification helps clarify the relations between various explications of reduction that have been offered in the past, especially if a distinction is maintained between the various epistemological and ontological issues that arise. A relatively new model of explanatory reduction, one that emphasizes that reduction is the explanation of a whole in terms of its parts is also presented in detail. Finally, the classification is used to clarify the debate over reductionism in molecular biology. It is argued there that while no model from the category of theory reduction might be applicable in that case, models of explanatory reduction might yet capture the structure of the relevant explanations.

The paper sets out a new strategy for theory reduction by means of functional sub-types. This strategy is intended to get around the multiple realization objection. We use Kim's argument for token identity (ontological reductionism) based on the causal exclusion problem as starting point. We then extend ontological reductionism to epistemological reductionism (theory reduction). We show how one can distinguish within any functional type between functional sub-types. Each of these sub-types is coextensive with one type of realizer. By this means, a conservative theory reduction is in principle possible, despite multiple realization. We link this account with Nagelian reduction, as well as with Kim's functional reduction.