Strategy For Dualists
ABSTRACT: Dualists need to change their argumentative strategies if they wish to make a plausible case for dualism. In particular, dualists should not merely react and respond to physicalist views and arguments; they need to develop their own positive agenda. But neither should they focus their energies on constructing a priori arguments for dualism. Rather, dualists should acknowledge that what supports their view that consciousness exists and is a nonphysical phenomenon is observation, not argumentation. What is needed is a positive account of the nature of consciousness and the indispensable role that it plays in our lives, for it is only by showing the explanatory utility of the nonphysical that dualists can begin to discredit those who would deny its existence. In this paper, I try to give some idea of what such a positive theory of consciousness would look like. In particular, I argue for a theory of consciousness that contains a priori synthetic truths about the ontological nature and causal powers of consciousness.
Keywords: consciousness, dualism, physicalism, materialism, rationality, synthetic a priori.
quoted from: METAPHILOSOPHY, Vol. 32, No. 4 (July 2001) pp.395-418,
One might be skeptical about the very idea of a philosopher needing a strategy. Strategy is for generals and politicians, not philosophers. The philosopher argues for her positions and against those of her opponents; that is the sum of any strategy she could have or needs to have. But surely there are a variety of argumentative strategies that one might employ in attempting to render a philosophical position plausible. And it must be conceded that the argumentative strategies of the dualist have not been successful. At best, the dualist has fought the physicalist to a standstill. At worst, she is marginalized as unscientific and anti-naturalistic, and even as an annoying, useless person who tiresomely repeats her dualist intuition while physicalists do the real work of advancing our knowledge of the mind.
If the dualist sometimes seems to do nothing but endlessly repeat her dualist intuition, it is because she too often lets the physicalist set the agenda regarding the philosophy of mind. The debate between dualists and physicalists is not just one among many debates about various aspects ofthe mind—it is the central debate in the philosophy of mind.1 It is central because it determines what about the mind merits philosophical study. According to the dualist, the physicalist denies the existence of the very essence of the mind. And the dualist gets incensed about this denial because she finds this essential feature of the mind to be so interesting, in that it is inextricably intertwined in all kinds of surprising and fascinating ways with almost everything that makes human life interesting and worthwhile.2 If dualism is correct, what philosophy of mind should be about is explaining how and why the mind is intertwined with these other important aspects of human life. But typically the dualist has failed to pursue this constructive agenda. She has let herself be cowed by the physicalist into being merely reactive, boringly insisting on the dualist intuition even in the face of every new version of physicalism. In failing to pursue a constructive agenda, the dualist marginalizes herself. She insists that the physicalist is missing a certain phenomenon but, by failing to tell us why this phenomenon is interesting, she neglects to explain why we should care about its existence. Given the dualist's silence on the nature of this phenomenon, we are inclined to think that it is of little importance whether the dualist is right. The dualist needs to change the agenda in the philosophy of mind; she needs to stop worrying about responding to every last twist in the physicalist saga and instead start concerning herself with showing the indispensability of the mind (as the dualist understands it) to so many of the important features of human life. Such a demonstration of the explanatory utility of dualist mind would surely be the best possible refutation of physicalism.
My aim in this paper is to provide the dualist with some advice as to how to begin changing the philosophical agenda. In particular, I hope to explain why the dualist is perfectly justified in ignoring the physicalist and pursuing her own constructive agenda. I also hope to provide some concrete recommendations as to how the dualist might begin pursuing this agenda, despite the notorious difficulties dualists have faced in attempting to say anything positive about the nature of the mind.
Although the dualist needs to do more than merely repeat her dualist intuition, she does need to be very clear about what the content of this intuition is. For example, she needs to make clear that the dualist intuition is an intuition about the nature of a certain property, namely consciousness—it is not an intuition about the nature of the substance that can instantiate this property. The dualist intuition is one that directly supports property dualism, not substance dualism.3 The dualist should embrace Hume's claim that we are not acquainted in any direct way with the intrinsic nature of the self (Treatise I.iv.6). But she should insist that we are acquainted in a direct way with the nature of consciousness, for it is on the basis of this purported acquaintance that she puts forward her dualist intuition.
And what is the content of this dualist intuition about consciousness? Insofar as the dualist is opposing physicalism, she may be understood to be saying that consciousness is not a physical property. But such a formulation is not clear enough for our purposes, for it employs the notion of the physical—a notion which needs to be explained, for it is unclear what conditions a phenomenon must meet if it is to count as physical. We can find a clearer formulation of the dualist intuition if we keep in mind her concerns. Remember, the dualist opposes physicalism because she takes the physicalist to be denying the existence of consciousness. The dualist sees no difference between eliminativists and other physicalists in this regard. Why is the dualist so sure that the physicalist is denying the existence of consciousness? The dualist purports to be acquainted with the nature of consciousness, and as a result believes that consciousness is a simple property.4 The dualist will thus oppose any physicalist who takes consciousness to be a complex and/or causal property, for she takes such a physicalist to be denying the existence of the simple property in which the dualist is so interested. More generally, the dualist will oppose any reductive account of the mental; she denies that the essences of mental properties can be described with nonmental terminology. She will oppose not only type-type identity theorists, who identify mental properties with complex neurochemical properties, but also functionalists who identify mental properties with causal and/or teleological properties. The dualist intuition is that consciousness is a simple property, not a complex or causal property.
Whether the dualist intuition is equivalent to the claim that consciousness is not a physical property will depend on how the concept of the physical is understood. There are philosophers who affirm the dualist intuitionas just described, but nevertheless take themselves to be physicalists— because although they hold that the property of consciousness is distinct from certain complex properties that are understood to be physical, they also hold that the property of consciousness is related to those complex physical properties in ways that render consciousness itself a physical property.5 I do not wish to deny the intrinsic philosophical interest of the questions of how the simple property of consciousness is related to certain complex physical properties, and how these relations bear on the issue of whether consciousness is physical. (It is in relation to these questions that issues about supervenience may become relevant.) Nevertheless, I do insist that these questions are peripheral to what the dualist should be concerned about, namely, pursuing her own constructive agenda of showing the interest and explanatory utility of the simple property of consciousness.
What typically divides dualists and physicalists is their opposing answers to the question of whether there exists a simple property of consciousness, for, as I noted at the beginning of this paper, it is the answer to this question that determines what it is about the mind that merits philosophical study. So I will continue to refer to those who affirm the existence of the simple property of consciousness as dualists, and those who deny the existence of this property as physicalists, even though some of those in the former category might prefer to ally themselves with the physicalist camp. In other words, I shall say that those who affirm the dualist intuition are dualists, and those who deny it are physicalists. In accordance with this usage, I will assume (as is traditional) that the simple property of consciousness with which dualists purport to be acquainted is not a physical property, and I will also assume that the complex and causal properties with which physicalists identify mental properties are indeed physical properties.
In the previous section, I claimed that the dualist needs to be very clear about the content of her dualist intuition. This is necessary because the debate between dualists and physicalists is over whether this intuition is correct. But the dualist intuition also has importance for another reason. For although physicalists do not agree with the dualist intuition, there seems to be a sense in which they—and perhaps all of us, for that matter— share the dualist intuition. The intuition that consciousness is a simple property and not a complex physical property is often more loosely expressed as the idea that mind and body are different sorts of things. And although the physicalist denies that mind and body are different sorts ofthings, I think that most physicalists would at least acknowledge that the mind seems to be something different from the body. For even the physicalist must acknowledge that there at least seems to be a mind-body problem, a problem about how mind and body are related, and the reason that there seems to be a problem about how mind and body are related is because mind and body seem to be so different from each other. The physicalist ultimately solves this apparent problem by denying that it is actually a problem at all—she denies that mind and body are different from each other, and thus denies that there is any difficulty in explaining how they are related. But insofar as the physicalist acknowledges that there is at least an apparent problem here to be solved, she acknowledges that mind and body seem to be different from each other. We all share the dualist intuition, in that it seems to us to be true. The dualist intuition has an initial natural plausibility for us.
The plausibility of the dualist intuition is relevant here because it bears on the soundness of arguments that purport to show that this intuition is false. I am recommending to the dualist that she ignore the physicalist and pursue her own constructive agenda. In particular, I am suggesting that the dualist has more important things to do than respond to arguments for physicalism that claim that the dualist intuition is false, for there are good reasons to believe that such arguments will not be persuasive. They will be convincing only insofar as each of their premises is more plausible than the dualist intuition; given the natural plausibility of the dualist intuition, it seems most unlikely that physicalists will be able to come up with the needed premises. For example, some arguments for physicalism employ the premise that "all physical effects have sufficient physical causes" (Papineau 1998, 375).6 This physical causal closure principle is never argued for by physicalists; with a clear conscience, they simply take its plausibility for granted. Now perhaps it would be a nice thing in some sense if the physical causal closure principle were true—its truth would bestow on the world a kind of simple organizational structure which some might regard as aesthetically pleasing. But can anyone seriously maintain that the physical causal closure principle is more plausible to us than the dualist intuition itself? I submit not. The dualist intuition that consciousness is a simple property seems to us to be such an obvious truth because it seems to us that we are directly acquainted with the nature of consciousness. In other words, the dualist intuition purports to be an observational claim about one particular phenomenon, whereas the physical causal closure principle is a theoretical claim that concerns all physical effects, both known and unknown. I fail to see how such a large-scale theoretical claim can be more plausible than a single observational claim.7
I grant that if a purported observation cannot be repeated, then we might conclude that what purported to be an observation is not a genuine observation at all. But the dualist intuition does not claim to be based on some long-ago, one-time observation that has never been repeated. On the contrary, we take ourselves to have a continual acquaintance with consciousness, and we take ourselves to be constantly observing its simple nature. Of course even genuine observations can be misleading and nonveridical, and the existence of hallucinations perhaps shows that it is possible for it to seem to me that I am observing something when in fact I am not observing anything at all. Thus it is possible for a proposition to seem to me to be true when it is not. I am as confident about the truth of the dualist intuition as I am about anything, but nevertheless I am modest enough to acknowledge the possibility that I am mistaken here. On the other hand, I am not going to take this possibility seriously unless the physicalist produces a plausible explanation for how I could have been led to make such a mistake. It is not enough for the physicalist to set forth arguments against the dualist intuition, for some of the premises of these arguments will always strike us as less plausible than the dualist intuition itself. If the physicalist wants the dualist to take her seriously, she needs to undermine the natural plausibility that the dualist intuition has for us, by showing how even a physicalist who denies the truth of the dualist intuition can nonetheless explain why we are naturally inclined to find this proposition to be true.
Note that it is not enough for the physicalist to come up with just any story as to why so many have come to believe the dualist intuition; rather, she needs to come up with a plausible story. In particular, the story should not attribute gross stupidity to the believers in the dualist intuition, for many of the believers in the dualist intuition (myself included) are not grossly stupid. For example, David Papineau—one of the few physicalists to realize the importance of explaining the widespread belief in the dualist intuition—claims that the belief arises as the result of fallacious reasoning; specifically, he claims that the believer in the dualist intuition "succumbs to a species of the use-mention confusion" (1993, 177). I must reject Papineau's explanation, for I am not so grossly stupid as to have committed the fallacious reasoning that he describes. In fact, I will go so far as to say that I have never, at any period of my life, been so stupid as to have committed the fallacy described by Papineau. For Papineau is not describing some subtle species of the use-mention confusion in which the distinction between use and mention is somehow hidden within the recesses of a complicated chain of reasoning and is thus likely to be confused. On the contrary, the fallacious reasoning he describes is a very straightforward example of a use-mention confusion.8 So not only do I find Papineau's explanation of why people believe in the dualist intuition to be incredible,I find it to be insulting, since it implies that my fellow dualists and I are grossly stupid. Until the physicalists come up with a better account of why so many of us are so sure that the dualist intuition is true, the dualist is perfectly justified in ignoring the physicalist and her arguments for physicalism.9
Not only should the dualist not waste her time responding to physicalist arguments that purport to show that consciousness is a physical property, she should also not waste time constructing a priori arguments that purport to prove to the physicalist that consciousness is not a physical property. For just as the dualist will not be persuaded by the physicalist's arguments, so the physicalist will not be persuaded by the dualist's arguments. That the simple property of consciousness is instantiated in the (actual) world is a contingent claim that can only be known empirically; it cannot be proven by a priori philosophical arguments. The dualist needs to remember that the reason why she feels so confident that the dualist intuition is true is because she takes herself to have observed countless instances of her own consciousness. If the physicalist is committed to denying that she observes the simple property that the dualist claims to observe, there is nothing that the dualist can say that is going to convince her otherwise.
The dualist might be willing to acknowledge that one will not be able to prove to the eliminative physicalist that the dualist intuition is true, but might insist that one can prove this claim to other kinds of physicalists. For physicalists who are not eliminativists are at least willing to affirm the contingent truth that consciousness exists. So what divides the dualist and these kinds of physicalists is the question of whether consciousness is a simple property. The dualist may insist that it is a necessary truth that consciousness is a simple property, and therefore one will be able to provide a priori proofs for this claim. But the dualist will be no more successful in these attempts to convince noneliminative physicalists of the truth of dualism than she will be in her attempts to convince eliminative physicalists. Insofar as it is a necessary truth that consciousness is a simple property, it is because the concept of consciousness just is the concept of that simple property whose instances dualists claim to observe. So the dualist may insist that it is an analytic necessary truth that consciousness is a simple property, but she must acknowledge that the concept of consciousness is an empirical concept—that is, it is a concept of a certain observed phenomenon. Since the noneliminative physicalist claims not to be able to observe this phenomenon, she will not share the dualist's concept of consciousness. Any argument that the dualist comes up with to prove that consciousness is a simple property will assume a concept of consciousness that the noneliminative physicalist does not share, and so the noneliminative physicalist will naturally (and justifiedly, from her point of view) reject any such argument. She will find no difficulty in rejecting one or more of the premises of any such argument, given that she does not share the dualist concept of consciousness.
Of course the dualist will find such denials to be implausible, but surely they are no more implausible than the physicalist's denial of the dualist intuition itself. From the dualist point of view, there is nothing more obvious than the dualist intuition; the dualist should not be surprised that the physicalist who is willing to deny the dualist intuition will also be willing to deny premises of valid arguments for the truth of this intuition. The dualist will not be able to find premises for her arguments that she can in good conscience take to be more obvious than the dualist intuition itself.
Given that the physicalist will not and should not be persuaded by the dualist's arguments, the dualist should stop spending her time constructing such arguments. For not only are such arguments pointless—in that they will not and should not persuade anyone who does not already accept the dualist intuition—but they are also positively harmful, in that they convey a misleading impression as to what the support for the dualist position is. They convey the impression that what supports the dualist position are these very arguments themselves. But in fact what supports dualism is observation, not argumentation. Consider the kinds of arguments that have been employed in recent years to support dualism. Such arguments include Saul Kripke's modal argument, absent and inverted qualia arguments, andFrank Jackson's knowledge argument.10 All of these arguments have a similar structure: their premises all affirm various possibilities relating to how conscious states (and/or knowledge of conscious states) can exist or fail to exist; from these premises about how it is possible for consciousness to exist or not exist, these arguments offer conclusions about the actual nature of consciousness. But dualists do not reason from unsupported intuitions about the modal features of consciousness to conclusions about the actual features of consciousness. On the contrary, their reasoning proceeds in the opposite direction—they begin with beliefs about the actual nature of consciousness, beliefs which they take to be supported by observations of instances of consciousness, and on the basis of these, they form beliefs about possible ways that conscious states can exist or fail to exist.11 Dualists do not just happen to find themselves with modal intuitions about consciousness which they uncritically embrace; rather, their modal intuitions are derived from the dualist intuition itself, which is supposed to be supported by observation.
The dualist needs to be more honest and open with regard to why she believes in the dualist intuition. My impression is that some dualists are too embarrassed to admit openly that they think they can observe certain features of consciousness; they are worried about what physicalists will think of them if they make such a blatantly Cartesian admission. But dualists need to stop worrying about what physicalists think of them; they must start pursuing their own constructive agenda of providing a positive account of the nature of consciousness and of the indispensable role that it plays in our lives.
We should not be surprised that the dualist has failed to pursue her own constructive agenda. It is not obvious how one might go about saying anything positive about the nature of consciousness. After all, the dualist takes consciousness to be a simple property, and there seems to be a straightforward sense in which there is nothing to say about what a simple property intrinsically and essentially is. What I wish to do in the remainder of the paper is to show the dualist how she can pursue her constructive agenda despite the impossibility of saying what the simple property of consciousness is.
Remember that what the dualist needs to do is to explain how the property of consciousness is related to various interesting and important features of our lives. And if the dualist's explanations are to be understood,she has to make sure that her audience understands which property she is talking about when she refers to the property of consciousness. As we have seen, there is a sense in which she cannot say which property she is talking about. But she can show her audience which property she is talking about. The dualist purports to know which property she is talking about because she claims to have observed instances of this property; she is talking about a certain property which she has perceived. If the dualist's audience is to understand her when she talks about consciousness, she also has to make sure that they are perceiving the property of consciousness. And if they are to succeed in perceiving consciousness, they need to be looking in the right direction, so to speak. If I claim to be looking at some interesting phenomenon, and my companion claims to be unable to see it, then I tell her where to look, with the hope that she will then be able to discern it. What applies to external observation also applies to introspective observation. So the first task for the dualist is to somehow get her audience to focus on the phenomenon of consciousness. Of course, the professional physicalist will never admit to being able to perceive the simple property of consciousness, no matter how diligently the dualist attempts to point it out to her. But as I have repeatedly said, the dualist needs to stop responding to what the physicalist says. The dualist's audience is not the physicalist, but rather the open-minded person who is willing to listen to what the dualist has to say about why consciousness is such an interesting phenomenon.
I submit that the dualist has not done a very good job in pointing out the phenomenon of consciousness. In particular, dualists often fail to adequately distinguish between the things we are conscious of, and consciousness itself. Consider David Chalmers, for instance. Unlike some dualists, Chalmers does take some time to try to describe various examples of conscious experiences, in an effort "to help focus attention on the subject matter at hand" (1996, 7). His examples include (sensory) smells, tastes, and colors. The smells include "the musty smell of an old wardrobe, the stench of rotting garbage, the whiff of newly mown grass, the warm aroma of freshly baked bread" (8). The tastes include "the taste of Turkish Delight, of curried black-eyed pea salad, of a peppermint Lifesaver, of a ripe peach" (9). But as Chalmers' own descriptions show, we take these smells and tastes to be properties of physical objects, rather than of the mind. Smells, tastes, and colors are examples of things we are conscious of; they do not themselves count as instances of consciousness. Consider also Chalmers' discussion of an auditory experience. He writes of the "almost magical" experience of "hear[ing] a ring", and notes that "nothing about the quality of the ring seems to correspond directly to any structure in the world" (7). I agree with Chalmers about the quality of the ring, but nevertheless his emphasis is in the wrong place. The ring considered in itself, sensory though it may be, is not itself a kind of consciousness; it is the hearing of the ring that qualifies as a way of being conscious.
It may be objected that although common sense takes sensory smells, tastes, and colors to be properties of physical objects, science has shown us that in fact they are types of consciousness. But this is a tendentious way to describe the difference, if any, between the commonsense and scientific views of the status of sensory properties.12 At best, science suggests that smells, tastes, and colors cease to exist when we are not conscious of them. So science does recognize the commonsense distinction between consciousness and the things we are conscious of, and maintains the commonsense view that sensory properties are things we are conscious of, rather than types of consciousness. Science does not show that sensory properties are properties of the mind; instead, it (perhaps) shows that the instantiation of these properties is dependent on their being perceived by the mind.
Common sense takes sensory properties to be properties of physical objects, and so must have a way to think about the nature of the mind independent of these sensory properties. The way that it thinks of the mind is as the substance that instantiates the property of consciousness (i.e., the property of being conscious of things). The discoveries of natural science certainly give us no basis on which to think about the mind in any other way. Insofar as science moves sensory properties from the physical realm into the "mental" realm, it is because it suggests that sensory properties exist only when the mind is conscious of them. Science can place sensory properties into the mental realm only because it already has a way to think of the mental realm independently of these properties. It is only philosophy, not common sense or science, that often fails to maintain the clarity of the distinction between the things we are conscious of, and consciousness itself.13 And insofar as the dualist succumbs to this philosophical tendency, she will not succeed in getting her audience to focus on the phenomenon at issue—the phenomenon of consciousness.
Of course I am not denying that sensory properties may have some role to play in getting someone to focus on the phenomenon of consciousness. In attempting to point her audience in the right direction, the dualist might begin by providing some examples of things that we can be conscious of, such as sensory properties. But she then needs to emphasize to her audience that they are conscious of these sensory properties, and it is the consciousness that she is interested in, not (or not only) the sensory properties. Insofar as the dualist reminds her listeners of the distinction between consciousness and the things we are conscious of, they will presumably be able to switch their focus from the sensory properties to consciousness itself. They will become conscious of consciousness, so to speak.14
The dualist now has her audience focused on the phenomenon of consciousness, and is therefore ready to present a positive account of consciousness. The dualist's account purports to be supported by her observational acquaintance with the property of consciousness and so, if others are to understand and verify this account, they need to be acquainted with this property also. But given that consciousness is a simple property, what will the elements of such an account be? The dualist account will have nothing to say about what consciousness is composed of, for consciousness, being simple, is not composed of anything. But there is more to a property than its compositional elements or lack thereof. In particular, the dualist will need to describe the ontological nature of consciousness, and will also need to describe some of the causal powers that flow from consciousness.
Let us begin with ontology. The dualist needs to specify the ontologicalcategory to which consciousness belongs. So far I have claimed that consciousness is a property as opposed to a substance, in that it is something that can be exemplified by different substances. But I have not yet said anything about the kind of property that consciousness is. The traditional dualist view is that consciousness is a relation, and if we keep in mind the aforementioned distinction between consciousness and the things we are conscious of, we can see the plausibility of this view. Consciousness is a relation in that instances of consciousness relate a subject of consciousness (i.e., a mind) to an object of consciousness. Consciousness is essentially relational in that it is impossible for (an act of) consciousness to exist without the existence of a subject and object of that consciousness—a subject and object that are related to each other via that act of consciousness. A subject cannot be conscious without being conscious of something, and that something is the object of the subject's consciousness. Insofar as consciousness is a property of mind, it is a relational property of mind; it relates the mind, in a certain special way, to objects of consciousness.15
If the dualist is going to succeed in explaining why consciousness is such an important phenomenon in our lives, she is going to have to elucidate the nature of this special way that consciousness relates us to objects of consciousness. I shall say something in a moment about how the dualist might go about accomplishing this task. But first it is worth pausing for a moment to reflect on the mere fact that consciousness is a relation of some kind for, if we do so, we can already begin to see ways in which consciousness is a special and even unique phenomenon.
Consider, for example, how the dualist purports to know that consciousness is relational. Although I began this section by noting that the dualist's account claims to be supported by observation, nevertheless theparticular claim that consciousness is relational should be understood to be a necessary synthetic truth that can be known a priori. One might say that what observation of consciousness reveals to us in the first instance is the quality of consciousness. Compare our observations of consciousness with our observations of colors—observation reveals to us the nature of the color qualities and, by reflecting on these observations, we learn various facts about these qualities, such as that the quality of orange is more similar to the quality of red than it is to the quality of blue. Whereas it is a contingent truth known by observation that orange things exist in the world (i.e., that there exist things with that quality characteristic of orange things), it is a necessary truth known by a priori reflection on certain observations that orange is more similar to red than it is to blue. Similarly, it is one thing to know that a certain kind of quality is instantiated in the world, and it is something else to know the ontological category to which that quality belongs. So it will be a synthetic truth that consciousness (i.e., the phenomenon with that quality revealed to us when we perceive instances of consciousness) is relational. Moreover, it will be a necessary truth: the claim is that it is impossible for consciousness to exist in the absence of a subject and object of the consciousness. This necessary truth cannot be known solely on the basis of observations of particular instances of consciousness. Rather the idea is that observation reveals to us the nature of the quality of consciousness, and a priori reflection on this quality tells us that it is impossible for it to exist otherwise than as relating a subject to an object of consciousness. Reflection tells us that it is the nature of this quality to "reach out," so to speak, to an object of consciousness.16 So we can see how observation is relevant to the claim that consciousness is a relation, even though the claim itself is known a priori. It is a contingent, empirical truth that the quality of consciousness exists in the world, but it is a necessary synthetic truth that can be known a priori that this quality is a relation.
Thus one way in which consciousness is special, if not unique, is that there are a priori synthetic truths to be known about consciousness. The claim that consciousness is a relation is only one such truth; I will subsequently describe other synthetic a priori truths that can be known about consciousness. It is because there are synthetic a priori truths to be known about consciousness that the philosopher, even without the help of the scientist, can provide a positive account of the nature of consciousness and its role in our lives.
But of course what makes consciousness a truly unique and perhaps even strange phenomenon is not the mere existence of a priori synthetic truths pertaining to its nature, but rather the content of these truths. It is the intrinsic nature of consciousness that is strange and unique. Consider, for example,how strange it is that consciousness should be a relation, as opposed to, say, a monadic property. Consciousness is a simple property, and one might naturally assume that simple properties would be monadic. Sensory properties, for example, are simple properties, and most philosophers take sensory properties to be monadic properties. It seems strange to construe a simple quality as relational, for to do so is, in effect, to say that one can understand how this quality can exist only in terms of the existence of other entities that are related to each other by means of this quality. But given the simplicity of the quality, why should it require the existence of these other entities in order to exist itself? How can these other entities help us to understand how the quality itself can exist? An act of consciousness and an object of consciousness are distinct existences—why, then, should there be a necessary connection between them? Despite the strangeness of construing the quality of consciousness as relational, reflection on this quality shows that indeed it is relational. Reflection shows that despite its simplicity, the nature of consciousness is to reach out toward a distinct object. The dualist should not downplay the strange and unique nature of consciousness; she should emphasize it. The dualist wants to show that consciousness is a phenomenon we should care about, because of the indispensable role it plays in our lives. But if she is to make the case that consciousness plays an indispensable role in our lives, the dualist must emphasize the special and unique qualities of consciousness, so as to make plausible the view that other phenomena would not be able to play the role in our lives that consciousness does.
The dualist's task is to show the indispensability of consciousness by explaining the special ways in which consciousness is related to the things that make human life interesting and worthwhile. Here of course the ontological nature of consciousness is directly relevant: it is because the quality of consciousness is a relation that consciousness can relate us in special ways to the objects of our consciousness. And consciousness can relate us in special ways to objects of consciousness because of the unique properties of the quality of consciousness. In the next section, I say something about how the dualist can elucidate these special ways in which consciousness relates us to objects of consciousness.
Given the simplicity of consciousness, it may not be obvious how the dualist is to elucidate these special ways in which consciousness relates us to objects of consciousness. But although the dualist cannot say anything about what consciousness is, she can say something about what consciousness does, and that the special nature of consciousness will be manifested in what consciousness can do. In other words, the dualist can describe some of the causal powers of consciousness, such causal powers being demonstrations of the special ways in which acts of consciousness relate their subjects to objects of consciousness.
The casual powers of consciousness will be manifestations of what consciousness is intrinsically, insofar as these causal powers flow from the intrinsic nature of the quality of consciousness. My claim here is that consciousness does have causal powers that flow from its intrinsic nature. Consciousness is a simple property; it is not itself a causal property of the mind. It is, however, the underlying categorical basis of certain causal powers of the mind. Moreover, some of these causal powers flow from the intrinsic nature of the quality of consciousness, in that it is not some contingent law of nature that these casual powers are conjoined with the quality of consciousness but, rather, there is something about the intrinsic nature of the quality of consciousness that confers upon it the causal powers in question—therefore it will be a necessary truth that consciousness possesses these causal powers. So although we cannot directly describe the special intrinsic nature of the quality of consciousness, we can describe the causal powers that flow from its intrinsic nature and, by doing so, we describe its intrinsic nature in an indirect manner.
Suppose that some causal power P of consciousness flows from its nature. As already noted, the claim that consciousness has this causal power will be a necessary truth. Moreover, it will also be a synthetic truth, for the claim is that consciousness, as a simple, noncausal property, is the basis of a certain causal power. Finally, I submit that this necessary synthetic truth can be known a priori. I am claiming not only that there are causal powers that flow from the nature of consciousness, but also that these causal powers flow from consciousness in an intelligible way, in a way that makes sense, so to speak, and therefore in a way that enables reason to know about them a priori. To say that causal power P flows from consciousness is to say that there is something about the intrinsic nature of consciousness that necessitates that consciousness has P. Given that P flows from consciousness in an intelligible way, if reason reflects sufficiently on the intrinsic nature of consciousness (with which it is acquainted through observation), it will be able to detect this substantive necessary connection between the intrinsic nature of consciousness and P. (Reason just is the capacity to detect intelligible necessary connections.) Reason will be able to apprehend how the causal power flows from the intrinsic nature of consciousness. Whereas contingent causal laws can be known only on the basis of observations of constant conjunction, an intelligible necessary connection between a causal power and its underlying categorical basis can be known a priori. Earlier I noted that it is a synthetic a priori truth that consciousness is relational, and that there are also other synthetic a priori truths to be known about consciousness. These other synthetic a priori truths include truths about some of the causal powers of consciousness. A good portion of the dualist's work in developing a positive account of the nature of consciousness will involve setting forth these synthetic a priori truths about the causal powers of consciousness.
Given that the existence of synthetic a priori truths is controversial, why do I wish to saddle the dualist with the task of providing us with suchtruths? Because I have reflected on the nature of consciousness, and I seem to have discovered such truths—in particular, I seem to have discovered that the intrinsic nature of consciousness is such that it can be the basis of certain kinds of causal powers. (I shall give examples of such truths presently.) Since I find nothing problematic about the idea of synthetic a priori knowledge, I take these apparent discoveries at face value.17 If a philosopher insists that there is no synthetic a priori knowledge about consciousness to be had, my first response is that such philosopher has not reflected sufficiently or carefully on the nature of consciousness.
My second response is that our possession of a priori synthetic knowledge about consciousness can explain some of our strongest intuitions about the nature of consciousness. Earlier, in Section III, I noted that we all share the dualist intuition that consciousness is a simple phenomenon. But I have suggested throughout this paper that many of us also strongly believe that consciousness is an important, indispensable, special, and even unique phenomenon. I submit that it is because of our a priori synthetic knowledge about consciousness that we have these additional beliefs about consciousness. Consciousness is unique in that it is the only phenomenon of which we can have a priori knowledge of some of the causal powers that flow from its nature. (We cannot have a priori knowledge of any of the causal laws of physical nature.) And as I shall explain in more detail in Section VIII, it is the causal powers that flow from the nature of consciousness that make it important and indispensable. We take consciousness to be important because of the important things that consciousness can do. We understand it to be indispensable because we can see (a priori) that consciousness is of a nature that enables it to do these important things, and we have difficulty seeing how anything else could have a nature that would enable it to do such things.
Another strong intuition that we have about consciousness is that epiphenomenalists are mistaken. Thus Chalmers, who has some sympathy for epiphenomenalism, nevertheless acknowledges that "many people find it [epiphenomenalism] counterintuitive and repugnant" (1996, 150). That we have a priori knowledge of some of the causal powers of consciousness explains nicely why so many of us find epiphenomenalism to be counterintuitive and repugnant.18 Epiphenomenalists typically attempt to explainaway our intuitions against epiphenomenalism by suggesting that we mistakenly infer from the constant conjunction of certain kinds of conscious states and other states that these conscious states are the causes of the other states.19 Such an account of our intuitions is unpersuasive: if our only evidence against epiphenomenalism were observations of constant conjunction, then epiphenomenalism would not seem so repugnant to us, for there are all sorts of cases where we are happy to acknowledge that As and Bs are constantly conjoined without there being a causal relation between them. Rather, I claim, we feel so strongly that consciousness is causally efficacious because we know a priori that the intrinsic nature of consciousness is such as to make it causally efficacious.20
Perhaps it will be objected that Hume has already shown that we cannot have a priori knowledge of the causal powers of anything. Although Hume certainly claims that we cannot have a priori knowledge of the causal powers of anything, he has by no means shown this claim to be true.21 Hume is trying to "prove a negative"—his strategy is to consider a wide variety of noncausal properties, to insist that we can obtain no a priori knowledge of causal powers that flow from those particular noncausal properties, and then to argue that the representative nature of those noncausal properties provides good inductive evidence for the general claim that we have no a priori knowledge of the causal powers of anything.22 But in fact Hume's choices of noncausal properties are not sufficiently representative: he does not consider the noncausal (relational) property of consciousness. He does not consider this property because he denies its existence. Hume, of course, is notorious for denying the existence of a self that is distinct from and conscious of "perceptions"; for Hume, all there is to the mind is a series of successiveperceptions that are related by resemblance and causation (Treatise I.iv.6). Although Hume explicitly denies only the existence of a substance that is conscious of perceptions and not consciousness itself, it is clear that he is committed to denying both; if he were to admit the existence of acts of consciousness, he would need what are, in effect, substances to be the subjects of those acts (Shoemaker 1986, 105). Note that, for Hume, the bundles of perceptions that constitute minds are related only by resemblance and causation, not by consciousness; in fact, nowhere does Hume recognize a relation of consciousness. Hume's experiential perceptions are such things as colors, tastes, smells, pains, emotions, and desires; they do not include states of consciousness of colors, tastes, smells, or anything else. So we should not be misled by Hume's talk of "perceptions" into thinking that he recognizes the existence of a relation of perception or consciousness. In short, Hume says nothing to challenge my claim that we can have a priori knowledge of some of the causal powers of consciousness.
Let me provide an example of a causal power of consciousness that we can know about a priori. A sensory experience is a state in which a subject is conscious of an object instantiating one or more sensory properties. It is a familiar idea that an experience has the causal power to produce true demonstrative beliefs, to the effect that the object of experience has the sensory properties in question. My claim is that it is not merely a contingent law of nature that experiences can cause such beliefs, but that this causal power of experience intelligibly flows from the intrinsic nature of the consciousness that is part of the experience. Philosophers have traditionally attempted to explain this causal power of experiences in terms of the subject of the experience being acquainted with, presented with, or given the object of experience. But what does such talk of acquaintance, presentation, and givenness really mean—what does it add to the mere claim that the experiencer is conscious of the object of experience? I suspect that the traditional philosopher is trying to get across the idea that there is something about the intrinsic nature of being conscious of an experiential object that necessitates that the experiencer will have the causal power to form certain kinds of true beliefs about the experiential object. The traditional philosopher is also trying to get across the idea that this substantive necessary connection between consciousness and the causal power in question is an intelligible connection, and can therefore be detected a priori by reason—by reflection on the intrinsic nature of experiential consciousness, reason can just see that such consciousness is suited to give rise to certain kinds of true beliefs about the experiential object. So the view that we can have a priori knowledge of necessary synthetic truths about some of the causal powers of consciousness turns out to be part of a very familiar and traditional way of thinking about the mind.23
Of course the view that there are necessary truths about the causal powers of consciousness should be familiar even to contemporary philosophers, for it is a principal tenet of analytic functionalism that certain truths about the causal powers of mental states are necessary truths. The functionalist errs in attempting to explain the necessity of these truths in terms of their supposed analyticity. In doing so, the functionalist ends up defining mental states in terms of their causal powers, and thus ignores what the dualist takes to be the essence of the mind: the simple, noncausal property of consciousness. But the functionalist should be credited with the insight that there are necessary truths to be known about the causal powers of mental states—an insight that is too often ignored by dualists, despite its importance for the dualist account of consciousness. The dualist should agree with the functionalist's claim that it is necessary that, for example, experiences can cause beliefs of certain kinds, but she should dispute the functionalist's account of this necessity. The dualist should insist that the necessity at issue is a substantive necessary connection between the noncausal property of being conscious of a sensory object and the causal power of producing certain kinds of beliefs about that object. It is an important part of the dualist's task to discern those causal powers of consciousness that flow in a necessary way from its intrinsic nature; in searching for these causal powers, the dualist would probably do well to begin with those causal powers employed by the functionalists in their definitions.
There is of course more to the dualist's task than merely listing synthetic a priori truths about consciousness, whether these truths be about the ontological nature of consciousness or about its causal powers. Ultimately, the dualist wants to demonstrate the importance of consciousness by showing how it is indispensably connected with features of human life that give it interest and meaning. The dualist needs to employ the a priori synthetic truths about the ontological nature and causal powers of consciousness to elucidate these connections between consciousness and these other features of human life. In the next and concluding section of the paper, I wish to give some idea of how the dualist might go about doing this. I will consider an important feature of human life with which consciousness is connected, and briefly sketch how synthetic a priori truths about consciousness can be employed to describe the indispensable role that consciousness plays in relating us to this feature of human life.
The feature of human life on which I want to focus is rationality. Human beings are rational beings, and certainly a good portion of the interest and value of human life comes from the role that rationality plays. As noted, the dualist's project is to explain how consciousness is related to variousimportant features of human life and, as part of this project, she needs to explain how consciousness is related to rationality. In particular, the dualist needs to show that rationality presupposes consciousness: humans can be rational in the ways that they are only because they are minds, that is, beings capable of instantiating the simple property of consciousness.
There are various aspects to our status as rational beings. On the one hand, we are rational in that we can reason—we can construct and evaluate arguments. An argument can be thought of as a series of propositions; a valid argument is one in which the proposition that is the conclusion logically follows from the propositions that are the premises. When a person reasons to a valid conclusion, she has a series of successive thoughts, the propositional contents of which constitute successive steps in a valid argument. But of course there is more to valid reasoning than having thoughts that mirror valid arguments in this way. It is not supposed to be some inexplicably lucky accident that our thought processes happen to track logical relations between propositions. Rather, the person who is reasoning to a valid conclusion is supposed to be doing something that intelligibly explains why she reaches that conclusion. In particular, the idea is that the thinker becomes conscious of some logical consequence of the propositional contents of certain beliefs that she already has, and therefore judges and forms the belief that such logical consequence is true. So reasoning seems to require consciousness. The paradigm instance of reasoning is conscious reasoning, that is, reasoning in which the successive thoughts are conscious thoughts. A conscious thought is a mental event in which the subject is related to a proposition via the simple quality of consciousness. The nature of consciousness is such that a subject that is related to a proposition in this way will intelligibly have the causal power to become conscious of logical consequences of that proposition, and will therefore be able to reason to conclusions that logically follow from that proposition. (In other words, it is a necessary synthetic truth that can be known a priori that a subject conscious of a proposition has the causal power to become conscious of logical consequences of that proposition.) It is only through consciousness that we become related to propositions in ways that enable us to reason about them.24
Our rationality is not exhausted by our capacity to reason; we are also rational in that we can have mental states that are rational. For example, we can have beliefs that are rational or, equivalently, beliefs that are justified, and insofar as beliefs that constitute knowledge are justified beliefs, our rationality makes it possible for us to possess knowledge. Here I will simply state, and not defend, my view that a mental state is rational if and only if it is caused in a rational way, and something is caused in a rational way if and only if it is the result of the exercise of a rational causal power. And a causal power is rational if and only if there is a necessary connection between it and its categorical basis that can be detected a priori by reason. In the preceding section, I argued that consciousness has rational casual powers, in that it has causal powers that intelligibly (i.e., rationally) flow from its nature. Moreover, it seems plausible to hold that physical properties do not possess rational causal powers, for it does not seem that the laws of physical nature can be known a priori. The traditional foundationalist view of justification is that only experiences and other beliefs can justify beliefs. Let us see how my claim that rational mental states are mental states caused in a rational way can make sense of this traditional foundationalist view. We have seen how (conscious) beliefs can cause other beliefs in a rational way through the process of reasoning. We have also seen how experiences can be rational causes of beliefs. Moreover, given that physical properties do not have rational causal powers, it seems reasonable to conclude, with the traditional foundationalists, that experiences and other beliefs are the only entities that can cause beliefs in a rational way. More generally, given that consciousness has rational causal powers, it follows that the mental states produced by the exercise of these powers will be rational mental states. And given that consciousness is the only property that has rational causal powers, it follows that we must be conscious beings if we are to have the capacity to have rational mental states.
Beliefs may not be the only mental states that can be rational. For example, insofar as there is such a thing as practical reasoning, it will be possible for conative states (such as desires) to be rational. And once we allow for the possibility of rational desires, we must also allow for the possibility of things that have value, for presumably a thing has value if it is rational to want it. So just as there are connections between consciousness and rationality that the dualist needs to elucidate, so also will there be connections between consciousness and value that the dualist will need to explain.
I hope that I have said enough to give a sense of what the dualist's constructive agenda should be, and how she can proceed to carry it out. The dualist should carry out the agenda I have set out for her because doing so is the best way to combat physicalism. We are all familiar with the ways in which rationality and value contribute to the richness of our lives. Once the dualist succeeds in showing that we can understand how these and other matters contribute to the richness of our lives by tracing the relations that these items bear to the simple, nonphysical property of consciousness, we shall also understand how consciousness itself indispensably contributes to the richness of our lives. And once we understand that, we shall stop paying attention to those who wish to deny the existence of this simple, wonderful property.
Corcoran Department of Philosophy 512 Cabell Hall, University of Virginia Charlottesville, VA 22904-4780, USA. email@example.com
1 The debate I am concerned with here is over whether the mind is physical and so, strictly speaking, I should characterize the debate as being not between physicalists and dualists, but between physicalists and those who deny physicalism (where those who deny physicalism would include both dualists and idealists). Nevertheless, given that we lack a familiar word to characterize those who oppose physicalism, and given that most of those who oppose physicalism today are dualists and not idealists, I will continue to speak somewhat loosely and to refer to all those who deny that the mind is physical as dualists.
2 Examples of dualist frustration with physicalism include Searle (1992, 9), who claims that "if you are tempted to functionalism . .. you do not need refutation, you need help," and Strawson (1994), who claims both that reductive physicalism "seems to be one of the most amazing manifestations of human irrationality on record" (53), and that eliminativists "seem to be out of their minds" (101). I should note that neither Searle nor Strawson characterizes himself as a dualist; see Section II for why I believe that they should nonetheless be classified as dualists.
3 I remain neutral on the question of whether property dualism entails substance dualism. For an argument that property dualism does entail substance dualism, see Foster 1991, ch. 7.
4 Where I talk of a simple property, other philosophers might prefer to talk of a primitive, basic, or fundamental property.
5 Such nonreductive physicalists include McGinn (1991), Searle (1992), Strawson (1994), and perhaps Nagel (1974).
6 Both Lewis (1966) and Papineau (1998) give arguments for physicalism that require this premise.
7 Further criticism of the acceptability of the physical causal closure principle can be found in Crane (1991) and Foster (1991, 198-201).
8 Specifically, Papineau distinguishes between two kinds of mental acts that can be used to refer to conscious experiences: "first-person" acts, and "third-person" acts (1993, 176). First-person acts include imagining and remembering; to employ a first-person act to refer to an experience is to "be in a state which is similar to the state constituting the .. . experience" (1993, 171). The subject somehow employs this "internal recreation of the original experience" (1993, 176) to refer to the original experience; first-person acts "refer by simulating their referents" (1998, 384). By contrast, third-person acts do not use copies of the experience to refer to it. Third-person acts refer to the experience by employing identifying descriptions of the experience, which contain only physical predicates. Papineau speculates that we fallaciously reason as follows: (1) since first-person acts do and third-person acts do not use copies of experiences, therefore first-person acts do and third-person acts do not succeed in mentioning (i.e., referring to) experiences; (2) since third-person acts use physical predicates, therefore third person acts refer to something physical; (3) therefore, the experiences referred to by first-person acts are not identical to the physical entities referred to by third-person acts. In Papineau's words, "we slide from (a) third-person thoughts, unlike first-person thoughts, do not use (secondary versions) of conscious experiences to portray conscious experiences to (b) third-person thoughts, unlike first-person thoughts, do not mention conscious experiences. There is no reason, however, why third-person thoughts about experiences, like nearly all other thoughts about anything, should not succeed in referring to items they do not use" (1993, 178). I agree with Papineau that there is no reason to conclude that third-person thoughts about experiences do not succeed in referring to experiences, which is why I think it absurd for Papineau to suggest that dualists and others fallaciously draw this conclusion. I fail to see why Papineau thinks that the fallacious reasoning he describes is "seductive" (1993, 178), and therefore also fail to see why he thinks it plausible that dualists would succumb to such reasoning.
9 Other physicalists who seem to be committed to the view that it is fallacious reasoning of the most obvious kind that is responsible for the popularity of the dualist intuition include Armstrong (1973) and Lycan (1987, 42-44, 77-78).
10 For Kripke's modal argument, see Kripke 1980. For the absent and inverted qualia arguments, see, for example, Block and Fodor 1972 and Chalmers 1996. For Jackson's knowledge argument, see Jackson 1982, 1986.
11 That dualists reason in this manner is suggested by Lewis's discussion of what he refers to as the "folk-psychological concept of qualia" (1995, 141).
12 Of course philosophers disagree as to whether there is a difference between the commonsense and scientific views of the status of the sensory properties. Those who hold that there is a difference here include Sellars (1963) and Mackie (1976); those who deny that there is a difference include McGinn (1983) and McDowell (1985). My concern here is not to resolve this dispute, but rather to argue that, however this dispute is resolved, neither common sense nor science holds that sensory properties are types of consciousness.
13 Moore goes so far as to claim that all philosophers have made the "self-contradictory error" of holding that "what is experienced is ... identical with the experience of it" (1903, 445). Today, philosophers blur this distinction by employing theoretical terms such as "what it is like," "qualia," "qualitative character," "subjective character," and "phenomenal character" to refer to the distinctively mental aspect of mental states. The problem with such terms is that it is often difficult to tell whether the philosophers who employ them mean to refer to instances of consciousness or to the sensory properties we are conscious of. Such terminology bypasses the commonsense distinction between consciousness and the things we are conscious of without putting anything in its place, and so is particularly unhelpful for the purpose of identifying the mental. I should note that consciousness and sensory properties are similar in that they both are simple properties. And insofar as consciousness is nonphysical by virtue of being simple, sensory properties will also count as nonphysical. But the fact that sensory properties are nonphysical does not make them mental. Consciousness is the essence of mentality, and insofar as sensory properties are not types of consciousness, they are not mental properties either. Here I agree with McGinn, who claims that "colors . .. constitute a third category, just as real as, but distinct from, mental and physical properties" (1996, 548). Nevertheless, given that I am not concerned in this paper with the nature of sensory properties, I will continue to describe myself as providing advice for dualists, not triadists.
14 See Brentano 1973, 101—37, for a discussion of how a subject is able to be conscious of his own consciousness. Moore (1903, 446, 450) emphasizes the difficulty of becoming conscious of consciousness, but insists that it can be done: "When we refer to introspection and try to discover what the sensation of blue is, it is very easy to suppose that we have before us only a single term. The term 'blue' is easy enough to distinguish, but the other element which I have called 'consciousness'—that which the sensation of blue has in common with the sensation of green—is extremely difficult to fix. That many people fail to distinguish it at all is sufficiently shown by the fact that there are materialists. .. . The moment we try to fix our attention upon consciousness and to see what, distinctly, it is, it seems to vanish: it seems as if we had before us a mere emptiness. When we try to introspect the sensation of blue, all we can see is the blue: the other element is as if it were diaphanous. Yet it can be distinguished if we look attentively enough, and if we know that there is something to look for."
15 This traditional view that consciousness is a relation is generally referred to as the act-object conception of mental states, the idea being that a mental state consists in a subject's act of consciousness directed towards an object of consciousness. Consciousness is characterized here as an act insofar as an act is "something which cannot exist by itself, but can only exist as a constituent in a complex, whose other constituent is its object" (Broad 1923, 252). Broad immediately goes on to note that the act "is, of course, the characteristically mental factor in such a complex" (ibid.). Broad argues for the distinction between the act of consciousness (the "act of sensing") and the object of consciousness (the "sensum") as follows: "It does seem clear that, when I have a sensation of a red triangle patch, some things are true of the patch itself (e.g., that it is red and triangular) which it is very difficult to believe to be true of my sensation of the red patch. If so, it seems necessary to hold that the sensation and the sensum are not identical; that the sensum is an objective constituent of the sensation; and that there is another constituent which is not objective and may be called 'the act of sensing' " (ibid., 257). See also Moore 1903, 444: "We have then in every sensation two distinct elements, one which I call consciousness, and another which I call the object of consciousness. This must be so if the sensation of blue and the sensation of green, though different in one respect, are alike in another: blue is one object of sensation and green is another, and consciousness, which both sensations have in common, is different from either."
16 Compare Yourgrau 1990, 109: "To refer to something is to strike it, wherever in the universe it might be, with the arrow of the mind ... It is an extraordinary feature of the mind that it can somehow, 'without traveling', reach out and strike at any conceivable corner of reality."
17 Chisholm (1977, ch. 3) and BonJour (1998) are two philosophers who argue both for the existence and the intelligibility of synthetic a priori knowledge.
18 Note that I am not claiming that we find epiphenomenalism to be logically contradictory. Although I am claiming that we have a priori knowledge of some of the causal powers of consciousness, the knowledge at issue is synthetic, not analytic, and so it is not a consequence of my view that epiphenomenalism is a logical contradiction. By contrast, analytic functionalism holds that we have a priori analytic knowledge of some of the causal powers of consciousness, and therefore it is a consequence of analytic functionalism that epiphenomenalism is a logical contradiction. But epiphenomenalism does not seem to us to be a logical contradiction, and so analytic functionalism faces an objection which my own view avoids. I discuss analytic functionalism further below.
19 See, for example, Jackson 1982, 133, and Chalmers 1996, 151-52, 159. Note that although Chalmers expresses sympathy with epiphenomenalism, he does not subscribe to the view himself.
20 I should also note here that I find arguments for epiphenomenalistic dualism no more persuasive than arguments for physicalism. All the arguments for epiphenomenalism with which I am familiar assume the premise that the "physical world is causally closed"; see, for example, Chalmers 1996, 150.1 have already explained why I need not accept this premise if doing so commits me to rejecting the dualist intuition (Section III). I would similarly argue that I have no reason to accept this premise if doing so commits me to rejecting my antiepiphenomenalist intuition.
21 Hume "affirm[s], as a general proposition, which admits of no exception, that the knowledge of this relation [of cause and effect] is not, in any instance, attained by reasonings a priori; but arises entirely from experience, when we find that any particular objects are constantly conjoined with each other" (Enquiry IV.i, 27).
22 Hume also purports to have a direct a priori argument that shows that we can have no a priori knowledge of casual powers; see Treatise, 86—87 (I.iii.6): "There is no object, which implies the existence of any other if we consider these objects in themselves, and never look beyond the ideas which we form of them. Such an inference wou'd amount to knowledge, and wou'd imply the absolute contradiction and impossibility of conceiving any thing different. But as all distinct ideas are separable, 'tis evident there can be no impossibility of that kind." See also Enquiry, 29—30 (IV.i). For decisive criticism of this "separability of distinct ideas" argument, see Stroud 1977, 47-52.
23 The notion of acquaintance is most closely associated with Russell; see, for example, Russell 1911. For a more recent defense of a Russellian notion of acquaintance, see McDowell 1986.
24 I wish to remain neutral on the question of whether there is such a thing as unconscious reasoning. In particular, a process may count as an instance of unconscious reasoning if it is analogous in relevant ways to conscious reasoning. My position here basically follows Stich's (1978), who argues that whether the unconscious processes described by cognitive scientists should count as inference depends upon whether these processes "are in important ways similar to more standard cases of inference" (513), where the more standard cases of inference are those which relate beliefs, and beliefs are such that one has "an ability to become aware of or to be conscious of the contents of one's beliefs" (504, emphasis mine).
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