Online research in philosophy

The paper criticizes standard functionalist arguments for multiple realization. It focuses on arguments in which psychological states are conceived as computational, which is precisely where the multiple realization doctrine has seemed the strongest. It is argued that a type-type identity thesis between computational states and physical states is no less plausible than a multiple realization thesis. The paper also presents, more tentatively, positive arguments for a picture of local reduction.

Forthcoming in Philosophy of Science. Despite some recent advances, multiple realization remains a largely misunderstood thesis. Consider the dispute between Lawrence Shapiro and Carl Gillett over the application of Shapiro’s recipe for deciding when we have genuine cases of multiple realization. I argue that Gillett follows many philosophers in mistakenly supposing that multiple realization is absolute and transitive. Both of these are problematic. They are tempting only when we extract the question of multiple realization from the explanatory context in which it is invoked. Anchoring multiple realizability in its theoretical context provides grounds for arbitrating disagreements. Doing so, I argue, favors the view advanced by Shapiro.

The ?Dimensioned? view analyzes (multiple) realization in terms of compositional relation, and the ?Flat? view analyzes (multiple) realization in terms of causal-functional mechanism. The two different analyses of realization lead to the disagreement about whether realization is transitive. The two views, perhaps not surprisingly, have different consequences on testing for multiple realization, and prescribe different ?reconstructions? for the evidential significance of observation for multiple realization. I examine the differences between the two views on testing for multiple realization within a model-selection theoretical framework. I claim that the model-selection theoretical framework provides a ground to discuss and assess evidence for multiple realization.

One theme in recent philosophical attention to neuroscience has been that closer, more serious attention to actual neuroscientific research, and its results, challenges the familiar view that psychological properties are multiply realized by neuroscientific properties. Shagrir, (1998), presents a number of diverse reasons to think that diversity in neuroscientifically identified structures and properties does not inevitably lead to multiple realization. Bechtel and Mundale, (1999), argue that neuroscientific practice extending over a century contradicts the consequences of the hypothesis that psychological functions are multiply realized. Bickle, (2003), argues that a series of animal models of the consolidation of short-term memories into long-term memories reveals that this process is uniquely realized by a single biochemical cascade involving cAMP, protein kinase A, and cAMP response element binding proteins. Shapiro, (2004), argues that experiments on neuroplasticity do not show that there are many ways in which a brain might be wired in order to achieve a given psychological function.

Multiple realization historically mandated the autonomy of psychology, and its principled irreducibility to neuroscience. Recently, multiple realization and its implications for the reducibility of psychology to neuroscience have been challenged. One challenge concerns the proper understanding of reduction. Another concerns whether multiple realization is as pervasive as is alleged. I focus on the latter question. I illustrate multiple realization with actual, rather than hypothetical, cases of multiple realization from within the biological sciences. Though they do support a degree of autonomy for higher levels of explanation and organization, they do not have the dire consequences critics of multiple realization fear. †To contact the author, please write to: Department of Philosophy, University of Cincinnati, P.O. Box 210374, Cincinnati, OH 45221‐0374; e‐mail: robert.richardson@uc.edu.

When conceived as an empirical claim, it is natural to wonder how one might test the hypothesis of multiple realization. I consider general issues of testability, show how they apply specifically to the hypothesis of multiple realization, and propose an auxiliary assumption that, I argue, must be conjoined to the hypothesis of multiple realization to ensure its testability. I argue further that Bechtel and Mundale (1999) go astray because they fail to appreciate the need for this auxiliary assumption. †To contact the author, please write to: Department of Philosophy, University of Wisconsin–Madison, 5185 Helen C. White Hall, 600 North Park Street, Madison, WI 53706; e‐mail: lshapiro@wisc.edu.

ABSRACT: An increasing number of writers (for example, Kim ((1992), (1999)), Bechtel and Mundale (1999), Keeley (2000), Bickle (2003), Polger (2004), and Shapiro ((2000), (2004))) have attacked the existence of multiple realization and wider views of the special sciences built upon it. We examine the two most important arguments against multiple realization and show that neither is successful. Furthermore, we also defend an alternative, positive view of the ontology, and methodology, of the special science. In contrast to the claims of recent critics, we show that methodological connections between the neurosciences and psychology are plausibly often the result of multiple realization.

Bechtel and Mundale (1999) argue that multiple realizability is not plausible. They point out that neuroscientists assume that psychological traits are realized similarly in homologous brain structures and contend that a biological aspect of the brain that is relevant to neuropsychological state individuation provides evidence against multiple realizability. I argue that Bechtel and Mundale adduce the wrong sort of evidence against multiple realizability. Homologous traits do not provide relevant evidence. It is homoplasious traits of brains that can provide evidence for or against multiple realizability.

Kim claims that Bechtel and Mundale's case against multiple realization depends on the wrong kind of evidence. The latter argue that neuroscientific practice shows neural states across individuals and species are type identical. Kim replies that the evidence they cite to support this is irrelevant. I defend Bechtel and Mundale by showing why the evidence they cite is relevant and shows multiple realization does not occur.