![Sample our Behavioral Sciences journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/110801/TOC-Subject-Sample-2021-Behavioral-Sciences.jpg"})
Abstract
In this review of Thomas W. Polger and Lawrence A. Shapiro’s The Multiple Realization Book I look at the positive account, Modest Identity Theory, that Polger and Shapiro advance. In §2 of this review, I outline P&S’s arguments against multiple realization and summarize the view they defend, Modest Identity Theory. In §3, I consider what consequences the adoption of Modest Identity Theory might have on the ontology of psychological or mental kinds. In particular, I highlight the ontological pluralism and anti-reductionism that Polger and Shapiro endorse. Modest Identity Theory tolerates multiple taxonomies of psychological kinds, which represents an important departure from earlier versions of Identity Theory. I conclude in §4 by arguing that the way Modest Identity Theory individuates psychological kinds very closely resembles the way that those kinds are individuated by functionalism. I argue that the causal properties individuative of psychological kinds can be used to group together distinct neuroanatomical characteristics. I illustrate this by describing research into the functional connectivity of the reading network. I conclude by emphasizing the value of using empirical evidence from neuroscience and cognitive science to inform the new pluralistic ontology of psychological and mental kinds with which Modest Identity Theory is compatible.
Notes
1. As Polger and Shapiro do in their book, I will, from now on, simply refer to alleged cases of multiple realization as cases of multiple realization, with the understanding that claims of multiple realization are empirical and subject to revision, such that some cases merely may have the appearance of multiple realization, but upon close inspection fail to count as examples of multiple realization for one reason or another.
2. And the characterization Polger and Shapiro provide can be contrasted with remarks by Hillary Putnam, which place the burden on identity theory, “Finally, the hypothesis [identity theory] becomes still more ambitious when we realize that the brain-state theorist is not just that pain is a brain state, he is, of course, concerned to maintain that every psychological state is a brain state. Thus if we can find even one psychological predicate which can clearly be applied to both a mammal and an octopus (say “hungry”), but whose physical-chemical “correlate” is different in the two cases, then brain-state theory has collapsed.” (Putnam, Citation1975, p. 436).
3. Russell Poldrack emphasizes this point while presenting a series of challenges to the methodologies used in neuroimaging studies, “Unfortunately, such task analyses are very rarely presented in neuroimaging papers. Whereas formal theories from cognitive psychology could often provide substantial guidance as to the design of such tasks, it is uncommon for neuroimaging studies to take meaningful guidance from such theories. Rather the task comparisons in many studies are based on intuitive judgements regarding the cognitive processes engaged by a particular task.” (Poldrack, Citation2010, p. 149).
4. For example, the maximum size of an insect is limited by the respiratory system possessed by insects. This is one of several examples Shapiro mentions when presenting his Multiple Constraints Thesis (Shapiro, Citation2004, p. 81).
5. Polger and Shapiro are adopting the interventionist account of causation that James Woodward (Citation2003) defends. They are not concerned with the particulars of the account, and wish simply to endorse an account of causation by which causal explanations pick out difference makers in the relevant systems (Polger & Shapiro, Citation2016, p. 207).
6. Muhammad Ali Khalidi (Citation2013) develops and defends an account of natural kinds where natural kinds are individuated by their causal profiles. He leaves the concept of causation itself relatively unanalyzed, though he mentions that his account is compatible with an interventionist account of causation (p. 208). In defending his account he presents a similar defense of the autonomy of special science kinds and explanations to the one offered by Polger and Shapiro.
7. An important upshot of their argument to functionalists is that the kind of autonomy they defend here does not leave room for exclusion arguments against the mental to be brought up. “Difference-making accounts of the sort we have in mind simply have no use for the principle of Explanatory Exclusion. They also, in our view, have no use for the principle of Causal Exclusion; and realization theorists can exploit that feature of our view to defend against causal exclusion arguments. But that is not the argument that concerns us at the moment.)” (Polger & Shapiro, Citation2016, pp. 207, 208).
8. Diffusion Tensor Imaging (DTI) takes information about the rate of diffusion of water molecules in the brain, gathered using MRI (Magnetic Resonance Imaging), to estimate the volume and coherence of white matter tracts in the brain. Greater volume or coherence of white matter tracts indicates greater neural connectivity between the two brain areas linked by that white matter.
9. One interesting proposal regarding the way that different brain areas may participate in multiple networks and thereby come to play roles in multiple different psychological or cognitive kinds come from Michael Anderson’s neural reuse hypothesis (Anderson, Citation2014). Anderson argues that a single region of the brain is used in multiple different cognitive tasks by being recruited into different networks at different times. Polger and Shapiro acknowledge that this is a prima facie problem for identity theory, but note that it does not itself count in favor of multiple realization, since it does not fit the pattern required for cases of multiple realization (Polger & Shapiro, Citation2016, p. 93). Anderson's emphasis on neural reuse does not conflict with the importance of knowledge about the brain to explaining psychological kinds, and so is consistent with the broader goals P&S embrace.