Matthew Rellihan

How can abductive reasoning be physical, feasible, and reliable? This is Fodor’s riddle of abduction, and its apparent intractability is the cause of Fodor’s recent pessimism regarding the prospects for cognitive science. I argue that this riddle can be solved if we augment the computational theory of mind to allow for non-computational mental processes, such as those posited by classical associationists and contemporary connectionists. The resulting hybrid theory appeals to computational mechanisms to explain the semantic coherence of inference and associative mechanisms to explain the efficient retrieval of relevant information from memory. The interaction of these mechanisms explains how abduction can be physical, feasible, and reliable.

Fodor argues that our minds must have epistemic limitations because there must be endogenous constraints on the class of concepts we can acquire. However, his argument for the existence of these endogenous constraints is falsified by the phenomenon of the deferential acquisition of concepts. If we allow for the acquisition of concepts through deferring to experts and scientific instruments, then our conceptual capacity will be without endogenous constraints, and there will be no reason to think that our minds are epistemically bounded

Evolutionary psychologists attempt to infer our evolved psychology from the selection pressures present in our ancestral environments. Their use of this inference strategy—often called “adaptive thinking”—is thought to be justified by way of appeal to a rather modest form of adaptationism, according to which the mind's adaptive complexity reveals it to be a product of selection. I argue, on the contrary, that the mind's being an adaptation is only a necessary and not a sufficient condition for the validity of adaptive thinking, and that evolutionary psychology's predictive project is in fact committed to an extremely strong and highly implausible form of adaptationism. According to this “strong adaptationism,” the macroevolutionary trajectory of a population is determined by, and therefore predictable on the basis of, the selection pressures acting upon it. Not only is this form of adaptationism prima facie highly implausible, it requires making a number of naïve and likely false assumptions concerning the nature of heritable phenotypic variation in natural populations. In particular, it assumes that phenotypic variation is inevitably small in its extent, unbiased in its direction, and copious in its quantity. Because it is unlikely that these conditions obtain as a general rule, and even more unlikely that they obtained in early human populations, I conclude that there is little reason to believe that adaptive thinking can be used to infer the current structure of our minds from evidence of past selection pressures.

Some opponents of the incommensurability thesis, such as Davidson and Rorty, have argued that the very idea of incommensurability is incoherent and that the existence of alternative and incommensurable conceptual schemes is a conceptual impossibility. If true, this refutes Kuhnian relativism and Kantian scepticism in one fell swoop. For Kuhnian relativism depends on the possibility of alternative, humanly accessible conceptual schemes that are incommensurable with one another, and the Kantian notion of a realm of unknowable things-in-themselves gives rise to the possibility of humanly inaccessible schemes that are incommensurable with even our best current or future science. In what follows we argue that the possibility of incommensurability of either the Kuhnian or the Kantian variety is inescapable and that this conclusion is forced upon us by a simple consideration of what is involved in acquiring a concept. It turns out that the threats from relativism and scepticism are real, and that anyone, including Davidson himself, who has ever defended an account of concept acquisition is committed to one or the other of these two possibilities.1.

One of the most important objections to information-based semantic theories is that they are incapable of explaining Frege cases. The worry is that if a concept’s intentional content is a function of its informational content, as such theories propose, then it would appear that coreferring expressions have to be synonymous, and if this is true, it’s difficult to see how an agent could believe that a is F without believing that b is F whenever a and b are identical. I argue that this appearance is deceptive. If we heed the distinction between the analog and digital contents of a signal, it is actually possible to reconstruct something akin to Frege’s sense/reference distinction in purely information-theoretic terms. This allows informational semanticists to treat coreferring expressions as semantically distinct and to solve Frege cases in the same way that Frege did—namely, by appealing to the different contents of coreferring expressions

Representationalism is widely thought to grease the skids of ontological reduction. If phenomenal character is just a certain sort of intentional content, representationalists argue, the hard problem of accommodating consciousness within a broadly naturalistic view of the world reduces to the much easier problem of accommodating intentionality. I argue, however, that there’s a fatal flaw in this reasoning, for if phenomenal character really is just a certain sort of intentional content, it’s not anything like the sort of intentional content described by our best naturalistic theories. These theories make intentional content a mere Cambridge property of intentional states, a property that can be gained or lost through changes to distinct and causally disconnected objects. But consciousness is manifestly not like this; consciousness cannot suffer a mere Cambridge change. Thus, whatever ground is gained by explaining the phenomenal in terms of the intentional is lost again by undermining our best attempts to explain the intentional in terms of the natural. A Pyrrhic victory at best

I argue that the subset theory of property realization cannot account for both the multiple realizability and causal efficacy of mental properties. It avoids the threat of causal exclusion by identifying every power of a realized property with some power of its realizer, but this entails that the different realizers of a multiply realizable property share their causal powers, and this just isn't so. A counterexample is produced as evidence. Thus, in its original form, the theory fails to account for the multiple realizability of mental properties. The theory can be amended to account for multiple realizability, but these amendments undermine its account of mental causation and thereby reintroduce the problem of causal exclusion. The subset theory is thus caught between the horns of a familiar dilemma for physicalist theories of mind.

As conceived by Kim, the causal exclusion argument targets all forms of nonreductive physicalism equally, but by restricting its focus to functionalist varieties of nonreductivism, I am able to develop a version of the argument that has a number of virtues lacking in the original. First, the revised argument has no need for Kim’s causal exclusion principle, which many find dubious if not simply false. Second, the revised argument can be adapted to either a production-based conception of causation, as Kim himself favors, or to any of a number of dependence-based conceptions, like the ones favored by many of Kim’s critics. And, finally, the revised argument does not have the objectionable consequence that all so-called higher-level properties are epiphenomenal, for it does not generalize in the way that Kim’s original version of the argument arguably does. Nor does it concede much to narrow the scope of the argument in the way proposed. Those who adopt nonreductive theories of mind do so, by and large, on the strength of functionalist arguments for the multiple realizability of mental states. If functionalism entails that mental properties are epiphenomenal, this thus deals a critical, if not quite fatal, blow to nonreductivism.

I argue that Kroedel's 'Simple Argument' for downward causation fails and that this failure has consequences for any attempt to establish the reality of downward causation by appealing to counterfactual theories thereof. A central premise in Kroedel's argument equivocates. On one reading, it is true but renders the argument invalid; on another, it renders the argument valid but is likely false. I dedicate most of my efforts to establishing the second of these two claims. I show that the purported physical effects of mental properties do not counterfactually depend upon the total realizers of these properties. If counterfactual dependence is necessary for causation, it follows that mental properties are not causes. If counterfactual dependence is merely sufficient for causation, it follows that no appeal to counterfactuals will by itself succeed in showing that mental properties are causes.

I argue for the epiphenomenality of functional properties by means of thought experiments and general principles. General principles suggest that an object’s causal powers nomologically supervene on its intrinsic properties and that its functional role does not. This implies that it is possible for an object to lose its functional role without undergoing any change to its intrinsic properties or causal powers. Nor is it difficult to conceive of such scenarios. Various thought experiments are introduced for just this purpose. But properties that can vary independently of an object’s causal powers in this way are epiphenomenal, for their instantiation by an object at a time makes no difference to the causal processes the object is involved in at that time. The same processes would have occurred even if such properties hadn’t been instantiated. The intrinsicness thesis is controversial, but it is not controversial that it is true of productive causation, and many believe that productive causation is the only form of mental causation worth having. Nevertheless, in the paper’s final section I consider dependence-based accounts of causation, which do not presuppose the intrinsicness of causal powers, and show that they too have difficulties accounting for the efficacy of functional properties.

It has been argued that nonreductive physicalism’s problems with mental causation disappear if we abandon the intuitive but naïve production-based conception of causation in favor of one based on counterfactual dependence and difference-making. In recent years, this response has been thoroughly developed and defended by James Woodward, who contends that Kim’s causal exclusion argument, widely thought to be the most serious threat to nonreductive mental causation, cannot even be given a coherent formulation within Woodward’s preferred interventionist framework. But Woodward has, even more recently, defended a pair of necessary conditions on mental causation and higher-order causation more generally, and it is here that the interventionist framework proves less friendly to nonreductive mental causation. Functionalism is arguably the most important species of nonreductive physicalism concerning specifically mental properties, but, as I argue, functional properties fail both of Woodward’s tests of causal relevance, one of them in two different ways. The problem, moreover, seems unique to functionalism, for other types of higher-order properties appear to pass Woodward’s tests. If functionalism faces defeat even in such friendly territory, its problems with mental causation are not an artifact of naïve metaphysics. They run deep.

Frankfurt‐style cases suggest that an agent's moral responsibility for an action supervenes on the causal history of that action—at least when epistemic considerations are held constant. However, PAP‐style cases suggest that moral responsibility does not supervene on causal history, for judgments concerning an agent's responsibility for an action are also sensitive to the presence of alternative—and causally idle—possibilities. I appeal to the causal modeling tradition and the definitions of actual causation that derive therefrom in an attempt to resolve this contradiction. I show that even the weakest definitions of actual causation proposed in the literature establish that some PAP‐style cases constitute genuine counterexamples to the supervenience thesis. I consider several responses to these counterexamples on behalf of the defenders of supervenience and show that they fail. Our best current thinking on causation thus appears to be inconsistent with an intuitive and widely held claim concerning the nature of moral responsibility.