Does the Mind Still ‘Matter’?: The (un)Viability of (Reductive) Materialism

In what follows I will offer a critical analysis of Jaegwon Kim’s essential argument against non-reductive materialism, and for a functionalist account of reductive materialism, which he calls ‘Descartes’ revenge,’ and which seems to me to be a definitively persuasive argument against any form of robust property-dualism. I will stand Kim’s argument up against the defense of a canonical non-reductive materialist, Stephen Yablo, and argue that Yablo’s defense is inadequate. I will maintain that Kim’s argument successfully establishes the conditional that if materialism about the mind is correct, then reductive materialism, in particular functionalism, about the mind is correct. However, I will then move on to consider more general arguments for/against materialism, and in particular focus on giving an exposition of two arguments offered by Laurence BonJour against materialism tout court, and aimed at functionalism in particular. I will conclude that BonJour’s arguments, although deceptively simple and straightforward, successfully evacuate all plausibility from (reductive, functionalist) materialism. I will end by observing that while BonJour (embarrassingly) opts for a return to property-dualism, I will take Kim’s argument, in combination with those of BonJour, to license the search for alternative views, one example of which I will gesture towards, though not develop.

One of the philosophical puzzles most distinctive and symptomatic of our present age is the problem of correctly relating the mind to the brain. The popularity of materialism has served to pronounce this problem, which Jaegwon Kim rightly calls “our mind-body problem,”[1] meaning a problem for materialists/naturalists. Beginning with the work of figures like Herbert Feigl and J.J.C. Smart, who both championed a type-identity version of reductive materialism about the mind, Kim traces the genealogy of this mind-body antinomy “as a mainstream metaphysical Problematik.”[2] Their goal had been to identify discrete mental events with discrete physical brain-state events, the suggestion being that “mental events could just be brain processes, and that scientific research could show this.”[3] Kim admits that the approach of figures like Feigl and Smart seemed, to him, “refreshingly bold and tough-minded,… in tune with the optimistic scientific temper of the times.”[4] However, their approach was surprisingly short lived, coming nearly still-born onto the intellectual scene. One of the key objections which dug its grave was Hilary Putnam’s argument from multiple realizability, according to which “an instance of pain in a human may be grounded in one neural property, and another instance of pain, say in a reptile, may be grounded in another,”[5] so that there can be no strict identification of discrete mental states with discrete physically realized brain-states. However, the failure of this central-state identity theory, far from inviting most philosophers to head in new directions, has managed to produce a sort of “anti-reductionist consensus”[6] among materialists.

This anti-reductionist thesis, or ‘non-reductive materialism,’ maintains that mental events/properties cannot be reduced to, or strictly identified with, physical events/properties in the way figures like Smart or Feigl had wished. The concern for non-reductive materialists thus became how to “shed the restrictive constraints of monolithic reductionism without losing [their] credentials as physicalists.”[7] In order to do this non-reductive materialists appropriated the language of ‘supervenience,’ claiming in effect that every mental event or property just supervened upon some physical event or property. For one thing to supervene upon another means something like that there is a sort of ontological and “asymmetric dependence”[8] of the one on the other. More technically, the mind-body supervenience thesis can the outlined as follows (assuming asymmetry):

Mental properties supervene on physical properties, in that necessarily, for any mental property M, if anything has M at time t, there exists a physical base (or subvenient) property P such that it has P at t, and necessarily anything that has P at a time has M at that time.[9]

This provided an apparently promising way for non-reductive materialists to understand the relationship (indeed, the dependence) of mental properties with(/on) physical properties. The “supervenience claim [seemed] physicalistically appealing,”[10] providing the materialist with the linguistic license to continue calling themselves physicalists in good faith, all while denying the strict reducibility of mental events or properties to physical events or properties. Moreover, it aimed to do this while avoiding any slide into unwholesome views like epiphenomenalism or eliminativism by maintaining the reality of both mental properties and their causal efficacy. Mental events supervene asymmetrically and irreducibly upon physical events in such a way that “mental properties are distinct from but nonetheless “nothing over and above” physical ones.”[11] Hence, ‘supervenience-talk’ became the preferred way in which the non-reductive materialist could marry the irreducibility of mental properties to her physicalist commitments.

Jaegwon Kim, however, registers a complaint with the general strategy of these non-reductive materialists, insisting that “we cannot make the problem go away by making [such] simple and inexpensive repairs,”[12] as just appealing to ‘supervenience.’ In his submission, the general attitude of the non-reductive materialists:

[…] has been to offer solutions at minimal philosophical costs – that is, to show that the problem can be solved in a simple and easy way, without having to pay a heavy metaphysical price, like giving up property dualism and embracing either reductionism or eliminativism, or trying to live with epiphenomenalism, or even seriously contemplating a return to substantival dualism. These are what we might call “free lunch” solutions – or, if not entirely free, at least pretty cheap ones.”[13]

Kim enjoins his physicalist compatriots to treat the issue with the shrewdness of mind he thinks it deserves, and finds them guilty of having settled for a ‘free lunch’ solution which is at least short of intellectually thoroughgoing. Jaegwon Kim argues that this facile appeal to property-dualism coupled with supervenience leaves unresolved, and in fact even introduces, philosophical antinomies. For instance, it is difficult to see how mental events can stand in causal relations if there is a causal closure of the physical world (to which all materialists seem deeply committed), and physical events which subvene mental events are all caused by other physical events. The trouble, in other words, is that there are two alternative causal stories which, dialectically, cannot play nicely together. To illustrate, consider the case were mental property M1, which supervenes upon its subvenient realizer P1, causes M2, where M1 is sufficient for M2, but P2, whose sufficient cause is P1, is at once the subvenient realizer of M2, and sufficient without M1 to produce M2. The trouble is that M1 and P2 are independently sufficient causes of M2, that M2 supervenes upon P2, and that M1 cannot stand in any causal relation to P2. How, then, can M1 figure into the causal story for M2, if that story is complete just in case it involves reference to P2? Kim notes that “the presence of two causal stories, each claiming to offer a full causal account of a given event, creates an unstable situation requiring us to find an account of how the two purported causes are related to each other,”[14] and since the mental cannot bring about causal effects in the physical realm, pace the principle of causal closure, it becomes impossible to see how, if P2 is the sufficient, and only physical, cause of M­2, M2 could have any other cause.

More broadly, “Kim and others have complained that one does not explain a phenomenon by labeling it supervenient,”[15] and, in fact, “supervenience is not a mind-body theory[!]”[16] For one thing, supervenience seems to be compatible with a broad spectrum of views about the mind-body relation, from “reductive type physicalism at one extreme to dualistic emergentism at the other.”[17] The supervenience-claim doesn’t specify any “metaphysically “deep” [dependence] relation”[18] between the mental and the physical, for it amounts to nothing more profound than covariance. However, it is incumbent upon “any putative account of the mind-body relation that accepts mind-body supervenience [to] specify a dependence relation between the mental and the physical that is capable of grounding and explaining mind-body supervenience.”[19] Philosophers like J.P. Moreland have problematized the issue even further for the materialist by presenting sustained argumentation to the effect that “strict physicalism [actually] excludes the supervenience thesis.”[20]

These difficulties, however, are merely the footnotes to a much more incisive criticism leveled against property-dualism by Jaegwon Kim. The whole trouble with Descartes’ substance dualism, he reminds us, was that in splitting the world up into two strictly distinct realms (i.e., between material substances and immaterial substances) Descartes made causal relation from either realm to the other unintelligible. How could an immaterial substance ‘push’ or ‘pull’ a material substance, how could it ‘touch’ it at all, and how could the material substance effect the immaterial? This was, so the textbook story goes, the Achilles’ heel of (at least Cartesian) substance-dualism. However, there is, Kim suggests, “an instructive parallel between Descartes’ mind-body problem and the way the current debate on mind-body causation arose.”[21]

Although the current debate was catalyzed by Donald Davidson’s anomalous monism,[22] the problem easily generalizes to “all forms of non-reductive physicalism or property-dualism.”[23] In brief, Davidson wanted to posit both that mental phenomena, were “constitutively distinct from physical phenomena,”[24] being “essentially normative and governed by the principles of rationality,”[25] and that there was nevertheless an “intimate causal commerce across the two domains.”[26] Thus, Davidson seems to invite upon himself the full philosophical scorn heaped previously upon Descartes, the only difference being that, while for Descartes “it was the dualism of substances which caused the trouble… [for Davidson,] it was his dualism of properties.”[27] This point should not be missed; what did Davidson in here was not some eclectic feature of his view, such as the anomalousness of the mental, but, rather, his property-dualism. A commitment to property-dualism, though, is shared by the non-reductive materialists. Thus “dualism is not dead, [but] only evolved,”[28] and the same problem which attaches itself to substance dualism threatens to undermine property-dualism just as definitively and insuperably as it did substance dualism. Kim publishes his criticism in the form of a dilemma-style reductio which he amusingly calls “Descartes’ revenge against the physicalists.”[29] His argument proceeds as follows:

(i) On property dualism, either mind-body supervenience holds or it fails.
(ii) If mind-body supervenience fails, there is no visible way of understanding the possibility of mental causation.
(iii) If mind-body supervenience holds, then there is no visible way of understanding the possibility of mental causation.
(iv) Therefore, on property dualism, there is no visible way of understanding the possibility of mental causation.

Kim explains that the physicalist will be committed to (ii) given her commitment to the causal closure of the physical world, and the recognition that the whole attraction of supervenience is supposed to be its ability to subsume “mental phenomena [into] the ambit of the physical.”[30] However, she will also, it turns out, be committed to (iii); as we saw briefly above, there is no way to make sense of the claim that M1 causes M2. Ex hypothesi, “to cause a supervenient property to be instantiated, you must cause its base property (or one of its base properties) to be instantiated,”[31] but that just entails, in this instance, that “under the mind-body supervenience assumption, mental-to-mental causation implies, or presupposes, mental-to-physical causation,”[32] which is unconscionable for any faithful physicalist. Thus we have on hand a veritable dilemma for the non-reductive materialists.

Jaegwon Kim points the way back to the ‘promised land’ of materialist reductionism by urging us to take functionalism seriously. We have already seen that it is impossible, given the argument from multiple realizability, to strictly identify some mental even M with some physical brain-state event P (which would require both M ≡ P, and M = P). However, since this is generally thought to be a problem for reductive materialism, it can with due intellectual propriety be asked how Jaegwon Kim intends to deal with this difficulty. Kim, first, takes inventory of two (popular?) strategies for dealing with the problems it raises, neither of which does he endorse. They are, nevertheless, worth exploring, even if only briefly, because they strengthen the argument for his own functionalist account by eliminating alternatives. The first of these theses is the suggestion that perhaps we can still maintain some species-specific reductions, so that “pain is correlated with, and realized by, one neural state in humans, by a different neural state in octopuses, and perhaps by some electrochemical state in Martians.”[33] Thus, we could maintain that, for any human ‘H’, and any mental state M, and physical brain state P: (∀x) Hx ⊃ (Mx≡Px). The principle difficulty with this, however, is that it doesn’t take multiple realization seriously enough.

Multiple realization goes deeper and wider than biological species, and… even in the same individual the neural realizer, or correlate, of a given mental state or function, may change over time through maturation and[/or] brain injuries.[34]

The other strategy is “the disjunctive strategy”[35] according to which any mental state M is mutually implied by some set of disjuncts Pi, each member of which is a physical realizer of M. Thus M ≡ (P1 v P2 v …Pn), and this account should work even if Pi has infinitely, or even indefinitely, many disjuncts. Kim dismisses this strategy, however, since he notes that “sentence disjunction [is] not predicate disjunction,”[36] and “by quantifying over properties, we cannot create new properties any more than by quantifying over individuals we can create new individuals.”[37] Having resolutely disqualified these alternative views of reductive materialism, he puts forth his view as being the only game (left) in town.

His proposal is to say that we must functionalize mental properties so as to make them second-order functional designators[38] of their respective first-order physical brain-state realizers. He explains;

For functional reduction we construe M as a second order property defined by its causal role that is, by a causal specification H describing its (typical) causes and effects. So M is now the property of having a property with such-and-such causal potentials, and it turns out that property P is exactly the property that fits the causal specification. And this grounds the identification of M with P.[39]

This strategy of functionalizing properties, which is just to construe second-order properties as functional designators of the causal properties of their physical realizers, “enables [functionalists] to escape the supervenience argument”[40] since they can once again be identified with the mental events construed as second-order designators of first order realizers. Thus if properties such as P1 and P2 are realizers of some mental even Ma, and P1 or P2 have the causal disposition of bringing about P3 upon which Mb ‘supervenes’ then Ma can be said to cause Mb only in some explanatory sense. Namely, insofar as Ma is the functional property of just having the property of P1 (or P2). Thus, Ma, on this account, functionally reduces to whichever Pn is its realizer. The seminal point is that the realizer, and not the functional property (which is merely a property-designator), has the causal capacities. Only it has ontological status. Kim is concerned principally about ontological economy, and by his count, the non-reductive materialist hasn’t managed to balance her metaphysical budget, but the functionalist has, and tidily.

Non-reductive materialists have, as might well be expected, given some arguments by way of defending their property-dualism. For instance, Jerry Fodor writes, in his essay Making Mind Matter More, that “intentional properties are causally responsible if there are intentional causal laws.”[41] The idea would be to stipulate a set of laws at one order of explanation, the mental, which may not be, as such, reducible to laws which hold at lower levels of explanation (just as the laws of biology may not ‘reduce to’ the laws of physics). Thus, explanations in physics, explanations in chemistry, explanations in biology, and explanations in the order of mental reality, can all be distinguished as offering explanations on such different orders that we needn’t expect the laws and explanations at one level to be translatable to the laws and explanations at the other, even if the other seems more fundamental.

Stephen Yablo also bravely declares: I find no fault with dualism, or with the associated picture of mental phenomena as necessitated by physical phenomena which they are possible without.”[42] Yablo offers a defense of his view, which is an attempt to hold together three desiderata: (i) that there is no causal conflict between the mental and the physical, (ii) that mental events/properties are not reducible to physical events/properties, and (iii) that there is an explanation of how the higher-level (the mental) and lower-level (the physical) are causally related.[43] He asks why it seems problematic for us to say that a mental event M2 causes a physical event P2, even though a physical event P1 also causes P2. The problem, he suggests, is that there is a principle of causal exclusion, such that if A is causally sufficient for B, and A, then C is no part of the causal story of B. Yablo suggests, however, that this principle does not work when A and C are related to each other as determinate to determinable. Given this exception, he suggests that “any credible reconstruction of the exclusion principle must respect the truism that determinates do not contend with their determinables for causal influence.[44]

To borrow a popular illustration,[45] Socrates’ guzzling hemlock is the cause of his death, and his guzzling entails his drinking, but it is equally appropriate to say that Socrates’ death was caused by his drinking hemlock as to say that it was caused by his guzzling hemlock. Guzzling hemlock is the determinable, drinking hemlock is the determinate. However, if a determinable is causally responsible for x, then its determinate is (also) causally responsible for x. Yablo’s own preferred example comes in the form of a story about a pigeon named Sophie:

“Imagine a pigeon, Sophie, conditioned to peck at red to the exclusion of other colors; a red triangle is presented, and Sophie pecks. Most people would say that the redness was causally relevant to her pecking, even that this was a paradigm case of causal relevance. But wait! I forgot to mention that the triangle in question was a specific shade of red: scarlet. Assuming that the scarlet was causally sufficient for the pecking, we can conclude by the exclusion principle that every other property was irrelevant. Apparently, then, the redness, although it looked to be precisely what Sophie was responding to, makes in reality no causal contribution whatever.”[46]

This story, Yablo thinks, is absurd – the exclusion principle, if it applies at all, cannot apply such that it excludes determinables from their determinates. However, mental properties and physical properties are related to each other as determinable and determinate. To schematize this idea, we can construct the following table:

Determinable (causes) Red Intentional States Drinking Hemlock
Determinate (realizers) Crimson Physical States Guzzling Hemlock

Therefore, there should be no problem, even if mental properties are irreducible to physical properties, in saying that a mental property causes a physical property in addition to another physical property causing (and being sufficient to produce) that same physical property. So, mental properties are irreducible, they figure into the causal story of physical events without conflicting with purely physicalistic causal stories (no doubt true), and the explanation of how mental properties and physical properties are related can be spelled out by appealing to an asymmetric supervenience relation. That seems to pretty much cover Yablo’s desiderata, but does it work? Not, at least, according to Kim.

The problem with this reasoning, from Kim’s perspective, is that it misidentifies the real difficulty with property-dualism. The problem isn’t with the exclusion principle. The problem is with the causal closure of the physical world! Mental events and properties are either, at bottom, physical, or else they can have no influence on the physical world. If they are physical then reductive materialism is true. If they are not physical then whether the exclusion principle is true or false has nothing at all to do with whether irreducibly mental events can cause physical events.

It seems reasonably well established that Jaegwon Kim’s reductive materialism, via functionalism, is the most, if not the only, viable form of materialism about the mind. Thus, Kim’s arguments ought to compel us to accept the conditional statement that if materialism about the mind is correct, then reductive materialism about the mind is correct. It bears asking, though, whether materialism about the mind is correct. Materialism, it is hardly disputable, is by far the perspective which enjoys the most by way of intellectual consent among philosophers today. However, as Laurence BonJour has commented:

I have always found this situation extremely puzzling. As far as I can see, materialism is a view that has no very compelling argument in its favor and that is confronted with very powerful objections to which nothing even approaching an adequate response has been offered.[47]

Materialism, he suggests, and I concur, “seems to be one of those unfortunate intellectual bandwagons,”[48] whose success is better explained by appeal to sociological factors than by appeal to philosophical considerations. He suggests that there are only a handful of arguments, all of them “flimsy, when subjected to any real scrutiny,”[49] in favor of materialism, beginning with “the inductive generalization from the conspicuous success of materialist science.”[50] This argument, best I can make out, is supposed to be that the probability of materialism, given the success of the natural sciences, is not only greater than it otherwise would have been, but, indeed, greater than the probability that materialism is false! Pr(M|S) >> Pr(~M|S). I, however, can find no justification for the claim that, for instance, Pr(M|S) > Pr(T|S), where ‘T’ stands for Theism. In any case, such an argument, even if it did work, would be exceptionally weak.

Two other arguments in favor of materialism are briefly discussed by BonJour, one of which is an appeal to Naturalism, which he says “seems to be even more obviously an intellectual bandwagon,”[51] to which philosophers subscribe “while offering little by way of clear argument or defense.”[52] The other argument is one from the principle of the causal closure of the physical world, which, as we have seen, was one of the essential physicalist commitments Kim exploited in arguing for his reductive materialism. BonJour notes that while “the closure principle does not by itself entail that materialism is true”[53] it narrows the alternatives down to materialism, epiphenomenalism or else some kind of realm in causal isolation from the physical realm. Given that these last two are “extremely unpalatable,”[54] appeal to the closure principle does provide a reasonably good argument for materialism. However, BonJour responds that arguing for materialism on the basis of an appeal to the principle of causal closure is to put “the cart in quite a flagrant way before the horse.”[55] He complains;

But why is the principle of causal closure itself supposed to be so obviously correct? Clearly this ‘principle’ is not and could not be an empirical result… I have no idea whether the principle of causal closure is true or not. More importantly, I cannot imagine how to rationally decide whether it is true without first arriving at a defensible account of conscious mental states.[56]

The difficulty posed by conscious intentional states and qualia, though, is the thorn in the side of materialism.

Turning then to the case against materialism, BonJour offers what he takes to be both a simple and definitive argument against materialism adapted from Frank Jackson’ famous ‘knowledge argument.’ He very briefly outlines the ‘knowledge argument’ in its original form, and it bears quoting him at some length to get it on the table.

Mary is a brilliant neurophysiologist, who lives her entire life, acquires her education, and does all of her scientific work in a black-and-white environment, using black-and-white books and black-and-white television for all of her learning and research. In this way, we may suppose, she comes to have a complete knowledge of all the physical facts in neurophysiology and related fields, together with their deductive consequences, insofar as these are relevant —thus arriving at as complete an understanding of human functioning as those sciences can provide. In particular, Mary knows the functional roles of all of the various neurophysiological states, including those pertaining to visual perception, by knowing their causal relations to sensory inputs, behavioral outputs, and other such states. But despite all of this knowledge, Mary apparently does not know all that there is to know about human mental states: for when she is released from her black-and-white environment and allowed to view the world normally, she will, by viewing objects like ripe tomatoes, learn what it is like to see something red, and analogous things about other qualitative experiences. ‘But then,’ comments Jackson, ‘it is inescapable that her previous knowledge was incomplete. But she had all the physical information. Ergo there is more to have than that, and Physicalism is false.’[57]

Having observed that (at least one of) the chief objection(s) to this argument has been that Mary would not be learning any new facts, but instead merely acquiring some new experience or “ability,”[58] BonJour insists that it is “surprisingly easy to modify the original case in a way that makes it utterly clear that there are facts that Mary does not know while she is in the black-and-white room and will learn when she emerges.”[59] He continues;

Suppose that while she is still in the otherwise black-and-white environment, two color samples are brought in: one a sample of a fairly bright green, approximately the color of newly mown grass, and the other a sample of a fairly bright red, approximately the color of a fire engine. Mary is allowed to view these samples and even to know that they are two of the ‘colors’ that she has learned about in her black-and-white education. She is not, however, told the standard names of these colors, nor is she allowed to monitor her own neurophysiology as she views them.[60]

Will she be able, “on the basis of her black-and-white knowledge, together with her new familiarity with the two colors,”[61] to deduce which colour is which? If, as seems obvious, not, then wouldn’t she be learning something new if she were to learn which was which? BonJour, not surprisingly, answers in the affirmative, insisting that “while she can learn all the objective physical facts, there are still certain subjective physical facts that she can’t learn” in the manner described. Jaegwon Kim concedes this point, to some degree, when he says:

I am with those who believe that the main trouble comes from qualia. Unlike the case of intentional phenomena, we seem able, without much difficulty, to conceive an exact physical duplicate of this world in which qualia are distributed differently (worlds with qualia inversions) or entirely absent (“zombie worlds”), although the latter possibility is more controversial… my doubts about the functionalist accounts of qualia are by and large based on the well known, and not uncontested, arguments from qualia inversions and the familiar epistemic considerations.[62]

This, however, is exactly where BonJour’s second argument picks up, suggesting that not only qualia, but even intentional states cannot be accounted for on (functionalist) materialism. The issue here is over whether a materialist has the resources to account for “conscious intentional content,”[63] whether, in other words, she can account for the essential aboutness of thoughts. BonJour explains again;

Here it will be useful to bring the brilliant neurophysiologist Mary briefly back onto the scene, even though the black-and-white aspect of her situation is no longer relevant. Suppose that Mary studies me as a subject and comes to have a complete knowledge of my physical and neurophysiological makeup as I am thinking these various thoughts. Can she determine on that basis what I am consciously thinking about at a particular moment?[64]

He notes that “a functionalist would no doubt say that it is no surprise that Mary could not do this”[65] while suggesting that this is merely because Mary would also, have to know the external causal relations of my internal states to things in the world. Here, BonJour suggests, we find merely hand waving in the direction of materialist dogma, for how could this ever be verified, and what arguments are there for thinking it so? He concludes that we have, in these two arguments, “the strongest of reasons for holding that the materialist account of reality is incomplete”[66] and that to suggest otherwise “is in effect just to insist that no fact of any sort can be allowed to refute materialism.”[67]

In conclusion, Fodor (to my mind rightly) declared that if mental causation isn’t real then it’s the philosophical apocalypse.

“If it isn’t literally true that my wanting is causally responsible for my reaching, and my itching is causally responsible for my scratching, and my believing is causally responsible for my saying…. if none of that is literally true, then practically everything I believe about anything is false and it’s the end of the world.”[68]

However, I have shown that Jaegwon Kim has given a powerful argument for thinking that property-dualism cannot be right, and that the materialist should be a reductive materialist. Merely adopting talk of ‘supervenience’ does not do anything to get the non-reductive materialist out of the metaphysical concerns which motivated the reductive materialists of the 1950’s and 1960’s. Kim has skillfully and forcefully presented an apparently indissoluble dilemma for property-dualism, and thus we can take his arguments as establishing with success that if materialism is true, then reductive materialism (in particular in the form of functionalism) is our only option.While Fodor insisted on making the mind matter more, Kim has (more successfully) insisted on making the mind more matter. However, Laurence BonJour has, with equal force and plausibility, demonstrated the inability of materialism in general to account for qualia, like colours, or even, contra Kim, for the intentionality of propositional attitudes. These arguments together provide strong reasons for concluding that the now popular form of property-dualism known as non-reductive materialism is not a viable option, and that, at bottom, this is at least as much due to its ‘materialism’ as it is to its ‘dualism.’ We ought, all of us, abandon materialism unless all other options are in even worse philosophical shape.

 

[1] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 2.

[2] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 1.

[3] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 2.

[4] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 2.

[5] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 10.

[6] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 8.

[7] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 3-4.

[8] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 6.

[9] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 9.

[10] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 6.

[11] McLaughlin, Brian and Bennett, Karen, “Supervenience”, The Stanford Encyclopedia of Philosophy (Spring 2014 Edition), Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/spr2014/entries/supervenience/&gt;.

[12] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 59.

[13] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 59.

[14] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 65.

[15] J.P. Moreland, “The Argument from Consciousness,” The Blackwell Companion to Natural Theology (2009): 282-343.

[16] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 9.

[17] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 15.

[18] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 14.

[19] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 14.

[20] J.P. Moreland, “Should a Naturalist be a Supervenient Physicalist?” Metaphilosophy 29, no. 1‐2 (1998): 35.

[21] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 57.

[22] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 57-9.

[23] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 58.

[24] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 58.

[25] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 58.

[26] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 57.

[27] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 57.

[28] Stephen Yablo, “Mental causation.” The Philosophical Review, Vol. 101, No. 2 (1992): 246.

[29] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 46.

[30] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 41.

[31] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 42.

[32] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 43.

[33] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 93.

[34] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 94.

[35] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 93.

[36] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 105.

[37] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 104.

[38] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 106.

[39] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 96.

[40] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 116.

[41] Jerry Fodor, “Making Mind Matter More,” in A Theory of Content and Other Essays, Jerry Fodor (MIT press, 1989): 137.

[42] Stephen Yablo, “Mental Causation,” in The Philosophical Review 101, no. 2 (1992): 250.

[43] See Paul Sperring, “Mental Causation and the Exclusion Problem,” http://www.richmond-philosophy.net/rjp/rjp14_sperring.php#endref11

[44] Stephen Yablo, Thoughts: papers on mind, meaning, and modality. (Oxford University Press, USA, 2008): 232.

[45] Stephen Yablo, Thoughts: papers on mind, meaning, and modality. (Oxford University Press, USA, 2008): 243.

[46] Stephen Yablo, Thoughts: papers on mind, meaning, and modality. (Oxford University Press, USA, 2008): 230.

[47] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 3.

[48] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 4.

[49] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 5.

[50] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 5.

[51] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 7.

[52] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 7.

[53] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 5.

[54] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 6.

[55] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 6.

[56] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 6.

[57] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 11.

[58] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 11.

[59] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 12.

[60] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 12.

[61] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 12.

[62] Jaegwon Kim, Mind in a physical world: An essay on the mind-body problem and mental causation. (MIT press, 2000), 101-2.

[63] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 17.

[64] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 17.

[65] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 18.

[66] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 15.

[67] Laurence BonJour, “Against Materialism,” in The Waning of Materialism: New Essays. Ed. Robert C. Koons & George Bealer, (Oxford: Oxford University Press, 2009): 15.

[68] Jerry Fodor, “Making Mind Matter More,” in Philosophical Topics 17, no.1 (1989): 77.