Fifty years ago J. J. C. Smart published his pioneering paper, “Sensations and Brain Processes.” It is appropriate to mark the golden anniversary of Smart’s publication by considering how well his article has stood up, and how well the identity theory itself has fared. In this paper I first revisit Smart’s text, reflecting on how it has weathered the years. Then I consider the status of the identity theory in current philosophical thinking, taking into account the objections and replies that (...) Smart discussed as well as some that he did not anticipate. Finally, I offer a brief manifesto for the identity theory, providing a small list of the claims that I believe contemporary identity theorist should accept. As it turns out, these are more or less the ones that Smart defended fifty years ago. (shrink)

According to the multiple realization argument, mental states or processes can be realized in diverse and heterogeneous physical systems; and that fact implies that mental state or process kinds cannot be identified with particular kinds of physical states or processes. More specifically, mental processes cannot be identified with brain processes. Moreover, the argument provides a general model for the autonomy of the special sciences. The multiple realization argument is widely influential, but over the last thirty years it has also faced (...) serious objections. Despite those objections, most philosophers regard the fact of multiple realization and the cogency of the multiple realization argument as plainly correct. Why is that? What is it about the multiple realization argument that makes it so resilient? One reason is that the multiple realization argument is deeply intertwined with a view that minds are, in some sense, computational. But we argue that the sense in which minds are computational does not support the conclusion that they are ipso facto multiply realized. We argue that the sense in which brains compute does not imply that brains implement multiply realizable computational processes, and it does not provide a general model for the autonomy of the special sciences. (shrink)

Multiple realizability says that the same kind of mental states may be manifested by systems with very different physical constitutions. Putnam ( 1967 ) supposed it to be “overwhelmingly probable” that there exist psychological properties with different physical realizations in different creatures. But because function constrains possible physical realizers, this empirical bet is far less favorable than it might initially have seemed, especially when we take on board the richer picture of neural and brain function that neuroscience has been uncovering (...) over the past forty years, in which all sorts of brain activities play crucial roles beyond all-or-nothing electrical signaling. Because of its evolutionary history, the brain’s metabolic and informational processes are inextricably intertwined. The resulting complex integrated functions impose more constraints on possible realizers than the clean, single-purpose functions usually cited as examples in discussions of multiple realizability—with ramifications for the functionalist and computationalist foundations of cognitive science, artificial intelligence, and the philosophy of mind. (shrink)

The thesis proposes, defends, and applies a new model of inter-theoretic reduction, called "Neo-Nagelian" reduction. There are numerous accounts of inter-theoretic reduction in the philosophy of science literature but the most well-known and widely-discussed is the Nagelian one. In the thesis I identify various kinds of problems which the Nagelian model faces. Whilst some of these can be resolved, pressing ones remain. In lieu of the Nagelian model, other models of inter-theoretic reduction have been proposed, chief amongst which are so-called (...) "New Wave" models. I show these to be no more adequate than the original Nagelian model. I propose a new model of inter-theoretic reduction, Neo-Nagelian reduction. This model is structurally similar to the Nagelian one, but differs in substantive ways. In particular I argue that it avoids the problems pertaining to both the Nagelian and New Wave models. Multiple realizability looms large in discussions about reduction: it is claimed that multiply realizable properties frustrate the reduction of one theory to another in various ways. I consider these arguments and show that they do not undermine the Neo-Nagelian of reduction of one theory to another. Finally, I apply the model to statistical mechanics. Statistical mechanics is taken to be a reductionist enterprise: one of the aims of statistical mechanics is to reduce thermodynamics. Without an adequate model of inter-theoretic reduction one cannot assess whether it succeeds; I use the Neo-Nagelian model to critically discuss whether it does. Specifically, I consider two very recent derivations of the Second Law of thermodynamics, one from Boltzmannian classical statistical mechanics and another from quantum statistical mechanics. I argue that they are partially successful, and that each makes for a promising line of future research. (shrink)

Thomas Polger and Lawrence Shapiro claim that unlike human-made artifacts cases of multiple realization in naturally occurring systems are uncommon. Drawing on cases from systems biology, I argue t...

Recently, several critics of the multiple realizability thesis have argued that philosophers have tended to accept the thesis on too weak grounds. On the one hand, the analytic challenge has problematized how philosophers have treated the multiple realization relation itself, claiming that assessment of the sameness of function and the relevant difference of realizers has been uncritical. On the other hand, it is argued that the purported evidence of the thesis is often left empirically unverified. This paper provides a novel (...) strategy to answer these worries by introducing a role for multiple realizability in the context of biological engineering. In the field of synthetic biology, bioengineers redesign the evolutionary realizations of biological functions, even constructing artificial chemical surrogates in the laboratory. I show how in the rational design approach to biological engineering, multiple realizability can function as a design heuristic in which the sameness of function and difference of realizers can be controlled. Although practically motivated, this engineering approach has also a theoretical, exploratory component that can be used to study the empirical limitations of multiple realizability. Successful realization of the engineering designs would amount to a concrete demonstration of multiple realizability, taking evidence for MRT beyond what is readily found in nature. (shrink)

Reductionists say things like: all mental properties are physical properties; all normative properties are natural properties. I argue that the only way to resist reductionism is to deny that causation is difference making (thus making the epistemology of causation a mystery) or to deny that properties are individuated by their causal powers (thus making properties a mystery). That is to say, unless one is happy to deny supervenience, or to trivialize the debate over reductionism. To show this, I argue that (...) if properties are individuated by their causal powers then, surprisingly, properties are individuated by necessary co-exemplification. (shrink)

Polger and Shapiro argue that their official recipe, a criterion for judging when the phenomenon of multiple realization exists, renders MR less widespread than its proponents have assumed. I argue that, although Polger and Shapiro’s criterion is a useful contribution, they arrive at their conclusion too hastily. Contrary to Polger and Shapiro, I claim that the phenomenon of multiple realization in the biological world, judged by their criterion, is not as scarce as they suggest. To show this, an updated official (...) recipe, namely a multiple mechanistic realization thesis, integrating Polger and Shapiro’s criterion with a compositional conception of realization, is developed. Then, three examples of varied kinds are examined, showing that cases of MR are not so hard to find in the biological world. (shrink)

Ethical reductionism is the best version of naturalistic moral realism. Reductionists regard moral properties as identical to properties appearing in successful scientific theories. Nonreductionists, including many of the Cornell Realists, argue that moral properties instead supervene on scientific properties without identity. I respond to two arguments for nonreductionism. First, nonreductionists argue that the multiple realizability of moral properties defeats reductionism. Multiple realizability can be addressed in ethics by identifying moral properties uniquely or disjunctively with properties of the special sciences. Second, (...) nonreductionists argue that irreducible moral properties explain empirical phenomena, just as irreducible special-science properties do. But since irreducible moral properties don't successfully explain additional regularities, they run the risk of being pseudoscientific properties. Reductionism has all the benefits of nonreductionism, while also being more secure against anti-realist objections because of its ontological simplicity. (shrink)

This thesis explores the possibility of composite consciousness: phenomenally conscious states belonging to a composite being in virtue of the consciousness of, and relations among, its parts. We have no trouble accepting that a composite being has physical properties entirely in virtue of the physical properties of, and relations among, its parts. But a long­standing intuition holds that consciousness is different: my consciousness cannot be understood as a complex of interacting component consciousnesses belonging to parts of me. I ask why: (...) what is it about consciousness that makes us think it so different from matter? And should we accept this apparent difference? (shrink)

The target of this article is the claim that natural selection accounts for the multiple realisation of biological and psychological kinds. I argue that the explanation actually offered does not provide any insight about the phenomenon since it presupposes multiple realisation as an unexplained premise, and this is what does all the work. The purported explanation mistakenly invokes the ?indifference? of selection to structure as an additional explanatorily relevant factor. While such indifference can be explanatory in intentional contexts, it is (...) not a causal factor at all in non-intentional nature. The upshot is that, once the necessary initial assumption about heterogeneity is accepted, there is no further explanation to do. (shrink)

Though multiple realization has been an important concept in the philosophy of mind and philosophy of psychology for more than fifty years, it has not been until quite recently that anyone proposed an actual theory of what multiple realization is. This paper argues that the most dominant current theories of multiple realization are unacceptable. It does so by mainly arguing for a particular methodology for theorizing about multiple realization. Rather than being mostly constrained by intuitions, as theorizing about folk notions (...) usually is, theorizing about multiple realization is, it argues, constrained by the theoretical context in which the concept was born. By the lights of this method for constructing theories of multiple realization, these current theories are unacceptable. (shrink)

It has often been thought that compositional variation across systems that are similar from the point of view of the special sciences provides a key point in favor of the multiple realization of special science kinds and in turn the broadly nonreductive consequences often thought to follow from multiple realization. Yet in a series of articles, and culminating in The Multiple Realization Book, Tom Polger and Larry Shapiro argue that an account of multiple realization demanding enough to yield such nonreductive (...) consequences implies that compositional variation is far less significant for the multiple realization of special science kinds than many have supposed. I argue, in contrast, that even on this demanding account, lower-level compositional variation may frequently support the multiple realization of special science kinds across the systems of interest, and that there is a good explanation for where Polger and Shapiro go wrong in drawing the contrary conclusion. I consider but reject Carl Gillett’s claim that different views about the significance of compositional variation for multiple realization phenomena should be traced to implicit disagreement about the metaphysics of realization. (shrink)

A common view is that the truth of multiple realization—e.g., about psychological states—entails the truth of functionalism. This is supposed to follow because what is multiply realized is eo ipso realized. I argue that view is mistaken by demonstrating how it misrepresents arguments from multiple realization. In particular, it undermines the empirical component of the arguments, and renders the multiplicity of the realization irrelevant. I suggest an alternative reading of multiple realizability arguments, particularly in philosophy of psychology. And I explain (...) the proper way to understand the relation between realization and multiple realization. (shrink)

Identity theories are those that hold that 'sensations are brain processes'. In particular, they hold that mental/psychological state kinds are identical to brain/neuroscientific state kinds. In this paper, I isolate and explain some of the key features of contemporary identity theories. They are then contrasted with the main live alternatives by means of considering the two most important lines of objection to identity theories.

We often face a bewildering array of different explanations for the same social facts (e.g. biological, psychological, economic, and historical accounts). But we have few guidelines for whether and when we should think of different accounts as competing or compatible. In this paper, I offer some guidelines for understanding when custom or norm accounts do and don’t compete with other types of accounts. I describe two families of non-competing accounts: (1) explanations of different (but similarly described) facts, and (2) accounts (...) which seem to differ but are really different parts or versions of the same underlying explanation. I argue that, while many types of apparent competitors don’t really compete with customs, there are some that do. I also describe some of the central problems, which suggest that custom accounts will compete poorly with their rivals. (shrink)

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. (shrink)

Proponents of mechanistic explanation have argued that dynamical models are mere phenomenal models, in that they describe rather than explain the scientific phenomena produced by complex systems. I argue instead that dynamical models can, in fact, be explanatory. Using an example from neuroscientific research on epilepsy, I show that dynamical models can meet the explanatory demands met by mechanistic models, and as such occupy their own unique place within the space of explanatory scientific models.