Jump to ContentJump to Main Navigation
Conceptual Analysis and Philosophical Naturalism$

David Braddon-Mitchell and Robert Nola

Print publication date: 2008

Print ISBN-13: 9780262012560

Published to MIT Press Scholarship Online: August 2013

DOI: 10.7551/mitpress/9780262012560.001.0001

Show Summary Details
Page of

PRINTED FROM MIT PRESS SCHOLARSHIP ONLINE (www.mitpress.universitypressscholarship.com). (c) Copyright The MIT Press, 2018. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a monograph in MITSO for personal use (for details see www.mitpress.universitypressscholarship.com/page/privacy-policy). Subscriber: null; date: 16 January 2019

The Argument from Revelation

The Argument from Revelation

Chapter:
(p.113) 5 The Argument from Revelation
Source:
Conceptual Analysis and Philosophical Naturalism
Author(s):

Daniel Stoljar

Publisher:
The MIT Press
DOI:10.7551/mitpress/9780262012560.003.0005

Abstract and Keywords

This chapter presents a take on the doctrine of revelation. Arguments from revelation are set out, after which, David Lewis’s response to this argument, together with related responses, is discussed. The “Canberra Plan,” at least in philosophy, is constitutively connected to compromise; it is often used for philosophical projects involving a compromise or replacement conception of some of the central notions both of philosophy and of ordinary life. Compromise usually stems from a commitment to a general metaphysical thesis about the nature of the world, namely, physicalism—a view that is inconsistent with intuitively plausible claims about the nature of apparently existing things. This chapter concludes by going back to the Canberra Plan and seeing what the reflections here have revealed about it.

Keywords:   doctrine of revelation, David Lewis, Canberra Plan, compromise, replacement conception, nature of the world, physicalism

1 Introduction

The story of Canberra, the capital of Australia, is roughly as follows. In 1901, when what is called ‘Federation’ occurred—that is, when the six colonies then occupying the territory of Australia decided to join forces and become one colony—it was naturally felt that there should be a capital city. But the rulers of the two most powerful cities, Sydney and Melbourne, could not agree which of them it was to be. (Nobody took seriously the claims of any other city.) So it was decided to build a completely new city more or less midway between them. In short, Canberra is constitutively connected to compromise.

In philosophy, what is called ‘the Canberra Plan’ is constitutively connected to compromise too; at any rate, the sort of philosophical project for which people use this term often or always involves articulating a compromise or replacement conception of some of the central notions both of philosophy and of ordinary life. The reasons for the compromise usually start from a commitment to a general metaphysical thesis about what the world is like, namely, physicalism. According to physicalism, the world is (in some hard-to-define sense) fundamentally or basically physical. We are then asked to agree that physicalism is inconsistent with various intuitively plausible claims about the nature of apparently existing things, such as people, colors, values, free will, experiences, ordinary physical objects, causation, and so on. How is this inconsistency to be resolved? The solution offered by proponents of the Canberra Plan is to compromise: to spell out replacement conceptions which on the one hand may reasonably be interpreted as successor conceptions to the intuitive or ordinary conceptions that cause the problem, but which on the other are compatible with the truth of physicalism. The guiding idea is that, though the (p.114) intuitively plausible claims about people, colors, and the rest partially constitute our ordinary conception of the natures of these things, there is no reason to treat them as nonnegotiable or sacrosanct.

This sort of philosophical project is vulnerable to the criticism that the search for replacement notions is unmotivated. If there is no conflict between physicalism and our ordinary conceptions, or if the reasons for supposing there is a conflict turn out to be without foundation, there is no stimulus to articulate replacement notions in the first place. One way to develop this criticism, a way defended in various places by Huw Price (e.g., Price 1997, 2004), is to say that the arguments for the inconsistency presuppose a unitary view about the function of assertion. In fact it was Huw Price and John Hawthorne (see O’Leary-Hawthorne and Price 1996) who originally coined the term ‘Canberra Plan’. Their idea was that just as Canberra is a place that does not contain or appreciate the diversity of other Australian cities, so too the Canberra Plan is an approach to philosophy that does not appreciate the diversity of the functions of assertion. Apart from the dubious sociological comparison on which it is based, this criticism suffers from being overly ambitious. What it entails is that problems about (say) experience and (say) causation have a similar intellectual origin, that is, not attending to the different functions of assertion. However, though this might be true, there is so far as I can see no compelling reason to believe it is true. Why should philosophical problems have a common origin rather than a whole series of unrelated origins? After all, scientific problems don’t in any serious sense have a common origin—why should philosophical problems?

A less ambitious way to implement the criticism that the Canberra Plan is unmotivated is to proceed case by case; that is, to consider in detail the arguments for the inconsistency in particular instances and to see whether those arguments are sound. This paper is an exercise in this less ambitious strategy. I will focus on the Canberra Plan as it emerges in one part of David Lewis’s discussion of the notion of experience. In his 1995 paper “Should a Materialist Believe in Qualia?,” Lewis suggests that the notion of experience that is implicit in folk psychology—that is, our ordinary notion of experience—is governed by a principle which he calls there ‘the Identification Thesis’ and elsewhere calls—following Mark Johnston 1992—the thesis of ‘revelation’. Lewis goes on to argue that physicalism —or ‘materialism’ as he prefers to call it (I myself will use these terms interchangeably here)—is inconsistent with the existence of experiences so conceived, and he then goes on to articulate, in accordance with the Canberra Plan, a replacement conception of experience. In what follows, (p.115) I will agree with Lewis that physicalism is inconsistent with the existence of experience so conceived but will raise some questions about whether experience ought to be conceived in this way. I will also argue, more generally, that there is no reason to believe that revelation is true.

My plan is this: In sections 2 to 7 I will set out what I take the doctrine of revelation to be. In sections 8 and 9 I will set out the argument from revelation. In sections 10 to 14 I will discuss Lewis’s response to this argument, and related responses. I will close in section 15 by returning to the Canberra Plan and asking what, if anything, our ruminations have revealed about it.

2 The Basic Idea

According to the thesis of revelation, having an experience puts you in a remarkable epistemic position. You know or are in a position to know the essence or nature of the experience; the only thing left to learn are facts about the experience that are nonessential or accidental—that is, facts extraneous to its essence. Suppose, for example, I have an itch in my toe. If revelation is true, I know or am in a position to know the essence or nature of the itch. The only thing left to learn are various facts about the distribution of something that has this essence or nature; for example, whether other people have similar itches, and when, and what having such itches causes and is caused by. Does the dean have a similar itch? Did he have it last Wednesday during the faculty meeting? Did it last the whole meeting? Of course questions of this sort raise further philosophical issues. For example, skeptics about other minds will say that I cannot know or justifiably believe that the dean has a similar itch. But skepticism about other minds is not to the point when it comes to revelation. Revelation says only that having an experience puts you in a position such that you have only the accidental truths about the experience left to learn. Whether you will learn those truths in fact is irrelevant.

This epistemic position—the one that, according to revelation, I am in with respect to this itch if I have it—is to be contrasted with the epistemic position I am typically in with respect to other things. Suppose, for example, I have a diamond in my pocket. It does not begin to follow that I know the essence of diamonds, or that the only things left to know are various facts about the distribution of things with this essence or nature—whether other people have diamonds in their pockets, and so on. For one thing, merely having a diamond in my pocket puts me in no epistemic position whatsoever. I may have a diamond in my pocket and have no idea what (p.116) diamonds are. Moreover, even if I know what diamonds are, in the ordinary sense that most of us do—I am able to reliably pick out diamonds at the jewelers, I know that the biggest diamonds come from South Africa, and so on—I may be quite ignorant of the chemical nature of diamonds, and so ignorant of something that is surely essential to them. So, according to proponents of revelation, having an itch puts one in an epistemic position with respect to itches that having a diamond does not put one in with respect to diamonds. I am in a position with respect to itches (and experiences more generally) such that the only thing left to learn are accidental truths. But I am not in that position with respect to diamonds.

Revelation has been held to be plausible both about experiences themselves, and for properties that experiences are by reputation intimately connected to, such as colors. In fact it is the literature on color that contains the largest discussion of revelation (cf. Johnston 1992; Strawson 1988, Lewis 1999, chapters 19 and 20; Jackson 1998a; as noted above, the terminology is due to Johnston). In the version that pertains to color, the thesis says that having an experience of, for example, red puts you in a remarkable epistemic position with respect, not to the experience of red, but to red itself. In particular, you know the essence or nature of red. The only things left to learn are accidental features. Whether revelation is true for colors in addition to experiences of color, and to experiences in general, is an interesting issue, and raises some questions that do not arise in the experience case. But, as in Lewis 1995, “Should a Materialist Believe in Qualia?,” I will concentrate here on experiences rather than on what experiences are of.

3 Revelation and Other Epistemic Principles

To say that revelation is true of experiences is in effect to advance a principle about the relation between experience, on the one hand, and knowledge or justified belief, on the other. For it is to say that if you have an experience, then you are in some sort of epistemic position with respect to it. But there is a whole class of different principles along these lines (see Alston 1971), and revelation is a fairly extreme principle within that class. It will be helpful in what follows to contrast revelation with two other such principles.

The first principle about the relation between experience and knowledge or justified belief that is not revelation is (what I will call) self-presentation. According to self-presentation, having an experience puts you in a position to know or justifiably believe that you are having the experience. Self-presentation (p.117) is neither necessary nor sufficient for revelation. It is not sufficient, for it is possible to be in a position to know that a property is instantiated without being in a position to know the essence of that property. Suppose I know perfectly well that there is a diamond in my pocket, and so know that the property of being a diamond is instantiated in my pocket. If I know there is a diamond in my pocket I am in a position to know it: trivially, if you know something you are in a position to know it. Am I then in a position to know the essence of diamonds? Surely not— knowing the essence of diamonds would at least involve knowing their chemical composition and maybe a good deal more besides. But chemical ignoramus that I am—or anyway may be assumed to be—I know nothing of such things. All I know is that I have a diamond in my pocket. So I am in a position to know there is a diamond in my pocket but not in a position to know the essence of diamonds.

Self-presentation is not necessary for revelation, because knowledge of the essence of a property does not entail knowledge that you yourself instantiate it. Suppose that revelation is true and that on having an experience I do indeed know its essence. To know the essence of the experience is not to know its accidental features. So it is consistent with revelation that I fail to know every accidental feature of the experience. However, that I myself have the experience is surely an accidental feature of the experience; it is no part of the essence of any experience that I have it. But then it is possible that I know the essence of the experience and not know that I myself have the experience.

The second principle about the relation between experience and knowledge or justified belief that is not revelation is—what I will call— understanding. According to understanding, if one has an experience at a certain time, then one understands what that experience is at that time. To say that one understands what the experience is is not to say that one has a verbal description to hand of the experience, or that one’s understanding will persist for any period of time. One’s understanding may be fleeting, and may be in an important sense nonconceptual or subverbal. What it means rather is that one has, perhaps tacitly, a certain kind of knowledge of what the thing is. From this point of view, what understanding says is that if a creature is psychologically complex enough to undergo a certain experience at a certain time, then the creature is psychologically complex enough to know what that experience is at least in the ordinary sense that is sufficient for understanding.

What is the relation between understanding so conceived and revelation? Understanding is necessary for revelation, for to say that one knows (p.118) the essence of experience is to say at least that one understands what experiences are. But it is not sufficient, for it is as yet an open possibility that one may understand an experience and yet not know its essence. Presumably I can understand what diamonds are without knowing their essence; maybe what is true for diamonds is true for experiences. So it does not immediately follow from the fact that one understands what itches are that one understands the essence of itches. Of course proponents of revelation are in effect asserting that this does follow, and that to understand an experience is to know its essence—but this is a controversial philosophical claim, something that requires argument and not assertion.

4 Revelation and Knowing What

The connection between understanding and knowing what that I have just made is reflected in an important aspect of Lewis’s discussion of revelation: his emphasis on the connection between revelation and knowing what. Lewis says that according to revelation: “we know exactly what…[our experiences]…are—and that in an uncommonly demanding and literal sense of ‘knowing what.’ If I have an experience with quale Q, I know that I am having an experience with quale Q and will afterwards remember (unless I happen to forget) that on that occasion I had an experience with quale Q” (Lewis 1995 [in 1999], 327). For Lewis, then, knowing the essence of something is an instance of a more general phenomenon, knowing what something is.

Now, as we have just seen, understanding something is also an instance of this general phenomenon, knowing what something is. What then is the difference between understanding and revelation? Lewis says that knowing the essence of something is knowing what it is in an “uncommonly demanding sense,” and goes on to explain what he means by saying that if one knows the essence of a thing in this demanding sense, one knows that experiences have F, where F is the essence of the experience. The suggestion here is that, though there are demanding senses of ‘knowing what’, there are also less demanding senses; moreover, sometimes when we speak of someone’s understanding something we mean only that he or she knows what it is in this less demanding sense. Presumably I may know what diamonds are but not know what they are in this demanding sense, namely because I do not know their essence. So it does not immediately follow from the fact that one knows what itches are that one knows what they are in the demanding sense that Lewis has in mind. Of course proponents of revelation are in effect asserting that this does follow, and that (p.119) knowing what experiences are is to know them in this demanding sense— but again this is controversial philosophical claim, something that requires argument and not assertion.

5 Varieties of Revelation

We have noted that revelation is to be contrasted with other principles about the relation between experience and knowledge, and pointed to the connection between revelation and knowing what. We should also note that there is a good deal of variation in the way in which the basic idea of revelation might be developed. I will mention five such ways briefly, before going on to develop the last of these in more detail in the next two sections. (We will return to some of the other ways in later sections.)

  1. (i) Revelation says that if have an experience I know or am in a position to know the essence of the experience. But which is it—know, or in a position to know? On the one hand, it is tempting to uniformly adopt the ‘in a position to know’ formulation. Revelation so interpreted does not assert outright that if I have an itch I know its essence; all it asserts is that if I have an itch then I am such that, were various conditions met—for example, were I to think harder or be smarter—I would know the essence of the experience. On the other hand, to interpret revelation this way is also to make it more obscure than it might otherwise be; after all, what exactly are the conditions such that were they met, I would know? In the presentation to follow, I try to ignore this issue as much as possible. So far as I can see, though the ‘in a position to know’ formulation is in some ways less controversial, it is nevertheless controversial enough, and the points I will raise will retain their force whichever formulation is in play.

  2. (ii) Revelation says that if I have an experience I know or am in a position to know the essence of the experience. But knowing the essence of experience might be interpreted as knowing, for example, that this itch is F, where F is in fact the essence of the experience; or it might be interpreted as knowing that F is the essence of this itch. On the second formulation, revelation requires that someone who has an itch has the concept of an essence, whereas on the first formulation, someone who has an itch need not have such a concept, even if revelation is true. In what follows I will adopt the first formulation. Surely it implausible that those who are itchy require the concept of essence.

  3. (iii) Revelation says that if I have an experience I know or am in a position to know the essence of the experience. But the knowledge at issue here could be either tacit or explicit. That is, revelation might be (p.120) the thesis that if I have an experience then the essence of the experience is in some hard-to-define sense ‘before the mind’. Or it might be the thesis that if I have the itch, then I know its essence, even if the fact that I know it is in some sense obscure to me. In what follows, I will adopt the second formulation. Surely it is implausible that those who are itchy have the essence of itchiness in the forefront of their minds.

  4. (iv) Revelation says that having an experience puts you in a position to know the essence of the experience. But—you might think I have taken too long to get to this question—what exactly is the essence of experience? More generally, what is the essence of a thing or property? Obviously, this is one of the more central and controversial notions in philosophy. In what follows, therefore, I will simply follow Lewis in supposing that the essence of a thing is “a property of it such that necessarily it has it and nothing else does” (Lewis 1999, 328). More generally, F is the essence of a just in case necessarily for all x, x =a iff x is F. From this point of view, when the proponent of revelation says that if I have an experience I know the essence of the experience he or she implies that if I have an experience of type E, then I know that E is F, where F is a property of E which necessarily it has and nothing else does. To know that E has F in this sense is to know a property of it that identifies it—it is for this reason, as I understand matters, Lewis refers to revelation as ‘the Identification Thesis’ (see, e.g., Lewis 1999, 328). (Lewis’s proposal about the essence of essence is controversial—in particular, see Fine 1994—but I will set these issues aside here. For some further but still too brief discussion, see chapter 11 of Stoljar 2006, and section 13 below.)

  5. (v) Revelation says that if I have an experience I know or am in a position to know the essence of the experience. This looks like a thesis about experience; certainly I have been interpreting revelation so far as if it is a thesis about experience. However, there is a slightly different way to look at the matter, according to which revelation is primarily a thesis, not about experience, but about understanding what an experience is. In the next two sections, I will spell out in more detail this dimension of variation in the basic idea of revelation.

6 Revelation and the Part–Whole Relation

As a preliminary to discussing the relation between revelation construed as a thesis about understanding and revelation construed as a thesis about experience, it is helpful to consider a comment made by Lewis that is initially extremely strange.

Lewis rejects revelation as it pertains both to the experience and to color, but he also says: “Maybe revelation is true in other cases—as it might be (p.121) for the part–whole relation” (“Naming the Colors,” chapter 20 in Lewis 1999, 353, n.21). This is unexpected. As we have noted, revelation is normally thought to apply to experiences or perhaps to properties that are by reputation intimately connected to experiences, such as colors. How then could revelation be true of the part–whole relation? We don’t have experiences as of the part–whole relation.

The way forward here is to notice that there are two slightly different theses doing business under the label ‘revelation’. The first, which I will call e-revelation, is a thesis about what happens when you have an experience. This is, or, for our purposes, may be assumed to be:

  1. (1) If Jones has an experience of type E, then Jones knows or is in a position to know, the essence of E.

    Obviously (1) is the thesis with which we have been operating so far. But e-revelation needs to be set apart from a related thesis, which I will call u-revelation. This concerns what happens, not when you have an experience, but rather when you understand what an experience is. This is, or, for our purposes, may be assumed to be:

  2. (2) If Jones understands what an experience of type E, then, Jones knows or is in a position to know the essence of E.

Obviously (2) is different from (1). To say that experience puts one in an epistemic position is not the same as saying that understanding does. More generally, e-revelation is not u-revelation.

This distinction permits us to explain Lewis’s initially odd remark about whole and part. When Lewis says that revelation is or might be true of the relation of whole and part, he does not mean to be invoking e-revelation, and therefore claiming that having an experience as of the relation of whole and part puts you in a position to know the essence of that relation. This claim lacks clear sense, because it is unclear what it is to have an experience as of the whole and part relation. Rather he is invoking urevelation, and means that if you understand what the relation of whole and part is, you know the essence of the relation. More generally, since u-revelation is a thesis about understanding, and is not a thesis about experience, it might be applied without oddity to domains, such as whole and part, in which experience has no role.

7 Revelation Identified

We have distinguished revelation construed as a thesis about experience— e-revelation—from revelation construed as thesis about u-nderstanding—urevelation. (p.122) But to distinguish these theses is not to deny they are closely related. On the contrary, there is a third thesis, which when combined with (1) will generate (2). This third thesis is none other than a version of the principle of understanding that we considered above. This is, or, for our purposes, may be assumed to be:

(3) If Jones has an experience of type E, he thereby understands what an experience of type E is.

As we have noted, like both revelation and self-presentation, understanding—that is, (3)—is one of a class of theses about experience, on the one hand, and knowledge or justified belief, on the other, but it is a fairly plausible principle within this class. So the two points we have isolated are these: first, e-revelation is distinct from u-revelation; and second, e-revelation follows from u-revelation together with a plausible further principle according to which if you have an experience of a certain type, then you understand what that experience is.

These considerations suggest a working hypothesis about the relation between e-revelation and u-revelation. The hypothesis is this: the basic doctrine at issue here is u-revelation; e-revelation is something that follows from this basic doctrine together with the view that if you have an experience you understand it. To put this differently, revelation may be factored into two claims. The first claim is understanding, namely, that if you have an experience, then you understand what it is; the second claim is u-revelation, namely, that if you understand what an experience is, you know or are in a position to know its essence. As we will see as we proceed, this working hypothesis is important when we consider the plausibility of revelation.

The fact that there are two different principles doing business under the label ‘revelation’ threatens to introduce a terminological confusion into our discussion. One way to avoid this confusion is to adopt the policy of always referring to u-revelation or e-revelation. In what follows, however, I will continue to talk without qualification about revelation. What I will mainly have in mind is e-revelation but readers should be able to discern from the context which notion is intended.

8 Revelation against Physicalism

So far I have been concentrating on what revelation is. I turn now to the question of what follows from revelation, and in particular, to the argument that if revelation is true, physicalism is false.

(p.123) Physicalism can obviously be understood in a myriad of ways, but here I will concentrate on the version according to which experiences of type E are identical to physical events of a certain type; more briefly, physicalism entails that E is identical to Phys (where Phys is some relevant type of physical state). From this point of view, the argument from revelation proceeds by pointing out that when revelation is combined with two agreed-on facts, it is inconsistent with physicalism.

Why is it that, when revelation is combined with two agreed-on facts, it is inconsistent with physicalism? Well, consider the following four claims:

  1. (4) If Jones has an experience of type E, then Jones knows or is in a position to know the essence of E.

  2. (5) Jones has an experience of type E.

  3. (6) The following is one essential truth about E: having an experience of type E is identical being in Phys.

  4. (7) Jones does not know, and is not in a position to know, that having an experience of type E is identical to being in Phys.

It should be clear, first, that these four claims are inconsistent. If (4) and (5) are true, then Jones knows the essence of E. But if (6) and (7) are true, Jones does not know the essence of E, because to know the essence of E would be to know that it is identical to Phys, and Jones does not know that. On the other hand, (4) follows from revelation; (5) is a statement of fact about Jones that we can assume or at least stipulate to be true—this is one of the agreed-on facts I mentioned; (6) follows from—or is an instance of something that follows from—the truth of physicalism; and (7) is another statement of fact about Jones that we can assume or at least stipulate to be true—this is the second agreed-on fact I mentioned.

If (4) to (7) are inconsistent, one of them is false. Setting aside (5) and (7), the only options are to deny (4) or (6). Friends of revelation argue that since (4) is true, (6) is false. That is the argument from revelation to the falsity of physicalism.

9 Options Revealed

How to respond? No doubt there are a number of possibilities, but three are particularly salient:

  1. (p.124) Response 1 Accept the argument as sound, and so reject physicalism on this basis.

  2. Response 2 Reject the argument by rejecting the thesis of revelation outright. This response might be put in rather blunt fashion as follows: “Sure, if revelation is true, we are in trouble. But why believe it? Revelation is just an insane fantasy that has been foisted on ordinary thought about experience by philosophers for their own dastardly purposes. There is no reason to take it seriously.”

  3. Response 3 Distinguish two conceptions of experience, an ordinary conception and a replacement conception. On the ordinary conception, (4) is true and (5) is false; more generally, revelation is true, and there are no experiences. On the replacement conception, (4) is false and (5) is true: there are experiences and revelation is false. This response, as I understand it, is the response of the Canberra Plan.

I will not attempt to discuss response 1 here beyond pointing out that presumably the reference to physicalism in the argument from revelation is not essential. Suppose a spiritualist identified having an experience of type E with being a thought in the mind of God. Presumably we could in that case imagine a person Jones—perhaps a member of some atheist cult—who didn’t know this, and yet had an experience of E. The argument from revelation, or a counterpart argument, could then be used to refute the spiritualist hypothesis about experience just as much as the materialist hypothesis. Nor is the reference to fairly well-known metaphysical positions essential. Suppose (never mind why) someone identified having an experience with having a certain arrangement of pumpkins. The argument from revelation, or a counterpart argument, could then be used to refute the pumpkin hypothesis just as much as the materialist or spiritualist hypothesis. In short, to accept the argument from revelation is tantamount to accepting a rather uncompromising form of primitivism about experience according to which itches, for example, are primitive items in the world, wholly distinct from everything else. Of course, there are questions about the plausibility of this sort of primitivism, but I will not consider these, or option 1, further in this essay.

Turning then to the other options, it might appear that there is a distinction without a difference between responses 2 and 3. Surely a proponent of response 2 will agree that there is a conception of experience that incorporates the notion of revelation. (If there were no such conception, it would be a simple matter to invent one.) And surely too a proponent of response 2 will agree that there is a conception that does not incorporate (p.125) the notion of revelation. To that extent then, response 2 and response 3 are on all fours: both accept that there are two conceptions of experience, one which incorporates revelation and one which does not; and both accept that if one adopts the conception that incorporates revelation then physicalism is true and there are no experiences, whereas if one adopts the conception that does not incorporate revelation, then physicalism is false and there are experiences. What then is the difference between response 2 and 3?

The difference between response 2 and 3 lies in their respective assessments of the two conceptions of experience that are at issue, the one that incorporates revelation and the one that does not. For proponents of response 2, the conception that incorporates revelation is a conception that has no claim on us. It is simply a conception that some philosophers have invented for purposes unknown. For proponents of response 3, by contrast, the conception of experience that incorporates revelation is the ordinary conception, or at least is a very natural one to adopt. Indeed, it is this claim of ordinariness or naturalness which as I understand things is central for proponents of the Canberra Plan. For them it is crucial that the conception of experience that causes the problem is our ordinary or natural conception. It is this fact that prompts the distinctive feature of their position, namely the search for a replacement conception of experience.

These considerations suggest the following strategy when thinking about how to respond to the argument from revelation, namely, see if the conception of experience that incorporates revelation is in fact one that is ordinary or natural. If it is not, or if the reasons for supposing that it is ordinary or natural turn out to be without foundation, we may conclude both that response 3 is mistaken and, correlatively, that response 2 is correct. In the next part of the essay therefore, I want to consider a number of comments made by Lewis in his discussion of these matters. As we will see, these comments provide a number of potential reasons for supposing that the conception of experience that incorporates revelation is the ordinary one. But what I will argue is that these potential reasons turn out to be less persuasive than they appear at first sight. If I am right, we are free to reject the conception of experience that incorporates revelation.

10 Revelation and Folk Psychology

In developing the point that the conception of experience that incorporates revelation is the ordinary conception, Lewis says that it is part of folk psychology:

(p.126) Folk psychology says, I think, that we identify the qualia of our experiences. We know exactly what they are—and that in an uncommonly demanding and literal sense of “knowing what.” If I have an experience with quale Q, I know that I am having an experience with quale Q and will afterwards remember (unless I happen to forget) that on that occasion I had an experience with quale Q. (Lewis 1995 [in 1999], 327)

Certainly, if folk psychology does say we identify the qualia of our experiences, a proponent of option 3 above would be on good ground in saying that the conception of experience that includes revelation is the ordinary one. But is it true that folk psychology says this? No doubt the question of what folk psychology says is ultimately an empirical question, somewhat like the question about whether folk physics says that medieval impetus physics is true. But even so I think it is appropriate to be fairly skeptical of this idea in the first instance.

First, as we noted earlier in our discussion there are many principles that connect experience on the one hand, with states of knowledge or belief on the other. Why think that revelation is the relevant one? For example, maybe all that is part of folk psychology is the doctrine of understanding, according to which if one has an experience one understands what it is.

Second, to suppose that revelation is built into folk psychology forces us to make some remarkable claims about the sort of cognitive sophistication that goes along with having simple experiences. Folk psychology says, I think, that animals on occasion feel pain. (Of course some people have denied this, but their views are rightly thought of as in violation in common sense.) And it is plausible also that folk psychology says that animals who feel pain understand what pains are—at least at the time they have them. But does folk psychology also say that animals who feel pain know or are in a position to know the essence of pain? That seems incredible. No doubt your average fox is a subject of suffering, but to suppose that he is also some sort of budding Aquinas is too much to bear.

Finally—this point is strictly ad hominem—Lewis himself seems to me to be uncharacteristically equivocal on whether revelation is built into folk psychology. Speaking in “Naming the Colors” of solutions to a problem about color which appeal to revelation, Lewis says: “But we materialists must dismiss this ‘solution’ as a useless piece of wishful thinking” (1999, 353). So although Lewis says in “Should a Materialist Believe in Qualia?” revelation is part of folk psychology, at least his language in “Naming the Colors” suggests something different.

(p.127) 11 Revelation and Obviousness

Why does Lewis believe that revelation is built into folk psychology? He writes in “Should a Materialist Believe in Qualia?”: “Why do I think it must be part of the folk theory of qualia? Because so many philosophers find it so very obvious. I think it seems obvious because it is built into folk psychology. Others will think it gets built into folk psychology because it is so obvious; but either way, the obviousness and the folk psychological status go together” (1999, 328). Once again, however, I think we should be skeptical of the supposed obviousness of revelation.

First, an obvious claim as I understand it is something which is either pretheoretically clear, or else it is something that is obvious in the context, that is, it is something that is presupposed by all parties to a dispute. But even if revelation were true, it is hard to see how it is obvious in either of these two senses. It is certainly not pretheoretically clear, if only because of its appeal to ideas about necessity and essence. And while there might be discussions in which the truth of revelation is presupposed, this discussion is evidently not one of those.

Second, the connection between obviousness and folk psychology depends on how one is thinking of folk psychology. In “Psychophysical and Theoretical Identifications” (1972) Lewis suggests that folk psychology may be thought of as a conjunction of platitudes. If by ‘platitude’ one means something obvious, then the obviousness of revelation is indeed built into folk psychology. But in later papers, Lewis suggests, in an explicit departure from his earlier view, a slightly different account of what folk psychology is. For example, in his 1994 “Reduction of Mind,” Lewis compares folk psychology to a body of tacit knowledge about a domain; on this view, you know folk psychology somewhat in the way that you know the syntax of your native language. If you think of folk psychology in this way, it is a bit unclear—at least it is unclear to me—that obviousness is to the point. Principles of syntax might well not be obvious and yet they might be tacitly known. In short, if one takes seriously the analogy between knowledge of folk psychology and knowledge of syntax, it is quite unclear that the supposed obviousness of revelation should entail or suggest that it is built into folk psychology.

12 Revelation and Kripke

I have been suggesting against Lewis that revelation is neither built into folk psychology nor obvious. But Lewis also offers some evidence of other (p.128) philosophers who think of it as philosophically central. He writes: “Kripke seems to be relying on the thesis in Naming and Necessity when he writes that ‘pain is picked out by its immediate phenomenological quality’ ” (Lewis 1995 [in 1999], 328, n.3).

As we have noted before, in Lewis’s terminology, ‘the Identification Thesis’ simply is revelation. So what he is saying here is that Kripke seems to be relying on revelation. But relying on revelation for what purpose?

At this point, it is a little hard to interpret exactly what Lewis has in mind. One possibility is that he thinks that Kripke is relying on revelation when he says that ‘pain’ is a rigid designator; as is well known there is a dispute between Kripke and Lewis on this point. In fact, however, it is hard to see why revelation would play a role here. The question of whether a term is a rigid designator is an empirical question the answer to which follows from, or is made plausible by, various semantic judgments about how the term functions in various modal contexts. It is not clear that revelation plays an essential role in these judgments.

A second possibility is that—according to Lewis—Kripke is relying on revelation when he distinguishes heat from pain; indeed Kripke is doing just this in the passage that Lewis quotes. Here is the Kripke passage in full:

In the case of the identity of heat with molecular motion, the important consideration was that although ‘heat’ is a rigid designator, the reference of that designator was determined by an accidental property of the referent, namely the property of producing in us the sensation S. It is thus possible that a phenomenon should have been rigidly designated in the same way as the phenomenon as heat, with its reference also picked out by means of the sensation S, without that phenomenon being heat and therefore its being molecular motion. Pain, on the other hand, is not picked out by one of its accidental properties; rather it is picked out by the property of being pain itself, by its immediate phenomenological quality. Thus, pain, unlike heat, is not only rigidly designated by ‘pain’ but the reference of the designator is determined by an essential property of the referent. (Kripke 1980, 152)

As I understand him, Kripke is here saying something like this. If we were to introduce or fix the reference of ‘heat’ we would wind up saying something like “let ‘heat’ denote the cause of heat-sensations.” In this case, the expression in terms of which we fix the reference is a definite description that denotes or expresses a contingent property of heat. But nothing parallel seems to be available in the case of ‘pain’. Indeed, it seems natural in the case of pain to suppose—though this is not explicit in the passage above—that, if we were to fix the reference of ‘pain’ we would wind up (p.129) saying something like ‘let pain be this feeling’. In this case the expression in terms of which we fix the reference of pain is an indexical that denotes on this occasion pain itself, and so denotes an essential property of pain.

However, if this is the right interpretation of what Kripke is saying in this passage, it is difficult to see him as relying on revelation, and for two reasons. First, Kripke is not here talking about understanding at all. However one clarifies the thesis of revelation precisely, it surely has something to do with knowledge or understanding. But the passage from Kripke mentions neither. All he says is that the reference-fixing story about ‘pain’ would not involve contingent property of the referent, while the reference-fixing story about ‘heat’ would involve a contingent property of the referent. How is it supposed to follow from this that, in the case of pain, understanding just is knowledge of essence?

It might be thought that, though Kripke’s point about reference fixing by itself does not entail anything about understanding, there is a natural extension of what he says that does. According to this extension, to understand heat is to know that it is the cause of heat sensations, whereas to understand pain is to know that it is this feeling. In short, understanding heat turns is interestingly different from understanding pain, for to understand heat means knowing a contingent fact about heat, that is, that it is the cause of heat sensations, whereas understanding pain does not involve knowing a contingent fact about pain.

However—and this is my second reason for supposing that Kripke is not relying on revelation—though it is true that one might develop what he says in this way, this fact provides no support for the idea that Kripke is presupposing revelation. For, if this idea about what is going on is correct, what Kripke is saying is that understanding pain means knowing that pain is this type of experience. And this in turn, as I understand matters, means something like this: to understanding pain is to have a certain kind of de re knowledge, that is, it is to know de re of some type of experience that it is pain. But on that interpretation Kripke is evidently not relying on revelation. The reason is that (where F is the essence of pain) revelation is not the doctrine that if one has an experience one knows of F, that pain is it. It is rather the doctrine that, if one has an experience, one knows that pain is F. That is, revelation does not involve de re knowledge of a property that is in fact the essence of the experience. It involves de dicto knowledge that one’s experience has that property.

Actually, this point is made by Lewis himself. Even if one denies revelation, he writes,

(p.130) there is no reason to deny that the broad, de re content of my knowledge does in the strongest sense identify qualia. Hitherto, I have been denying that the narrow de se and de dicto content of my knowledge identifies the qualia. But the broad content is constituted partly by my narrow de se self-ascriptions involving acquaintance, partly by the identity of the objects of acquaintance. Thus I may know de re of Fred that he is a burglar, without in any sense identifying Fred. Likewise, I may know de re of a certain physical property that it is among the qualia of my experience, without identifying the property in question. (Lewis 1995 [in 1999], 329–330)

As I understand Kripke in the passage above, he is saying that understanding pain means knowing de re of a certain property that it is among the qualia of my experience. But that is consistent with understanding pain without identifying it, and so consistent with the falsity of revelation.

13 Revelation and Two-dimensionalism

The passage from Kripke to which Lewis draws attention emphasizes a difference between heat and pain; and the problem for Lewis’s suggestion that Kripke is relying on revelation in this passage is that a difference between heat and pain does not entail or suggest a similarity between pain and whole and part. However, there is an argument in the vicinity that might be thought to show directly that pain is similar to the relation of whole and part. Moreover, this argument exploits something that is often thought to be present at least in embryonic form in the aspects of Kripke’s discussion we just considered, namely the two-dimensional approach to meaning and understanding.

We might spell out the issues here by drawing a distinction between two ways of spelling out the notion of an essence, a distinction I have so far ignored. As I indicated in section 4, I am here operating with the proposal that F is the essence of a iff necessarily a is F and nothing else is. Another way to say this is to say that F is the essence of a iff F in all possible worlds a is F and nothing else is. However, the phrase ‘in all possible worlds’ may notoriously be interpreted in two slightly different ways. One the first way, and the one that we have been adopting so far, the proposal comes out as: F is the essence of a iff in all possible worlds considered as counterfactual, a is F and nothing else is. Let us call the resulting notion of essence, the c-essence (for ‘counterfactual’). On the second way, the proposal comes out as: F is the essence of a iff in all possible worlds considered as actual, a is F and nothing else is. Let us call the resulting notion of essence a-essence (for actual). The distinction at issue here—between considering a possible (p.131) world as actual and considering a possible world as counterfactual—is a difficult one, but as a rough guide, we might say that being the watery stuff is the a-essence of water, whereas being H2O is its c-essence. (The phrase ‘considering a possible world as actual’ is due to Davies and Humberstone 1982, but it has received considerable attention in the recent literature. See, e.g., Jackson 1998a; Chalmers 2004; Stalnaker 2004.)

Now, if we assume that it is legitimate to draw a distinction of this sort between two notions of essence, it is a simple matter to define two notions of revelation. According to the first, revelation says that to understand something is to know its c-essence; let us call the resulting version of revelation, c-revelation. According to the second, revelation says that to understand something is to know its a-essence; let us call the resulting version of revelation a-revelation. Obviously, it is c-revelation that that has been the focus of this paper. What then of a-revelation? Well, here the surprising thing is that, while c-revelation is certainly a controversial doctrine, quite a lot of philosophers seem to adopt at least something like a-revelation as a quite general claim about understanding. Indeed, it seems to me that some of the philosophers who are attracted to two-dimensionalism and related ideas may be profitably interpreted as saying that, while c-revelation is almost always false, a-revelation is true when considered as a proposal about understanding. (Frank Jackson for instance, as I understand him, holds that to understand, e.g., water is to know that water is the watery stuff, i.e., “the kind common to the watery exemplars that we…are acquainted with” [Jackson 1998a, 49]. But as just indicated, the watery stuff is [what we here have called] the a-essence of water, i.e., a property that, in all possible worlds considered as actual, water has and nothing else does. Generalizing from this example, Jackson’s position appears to be a-revelation; to understand something is to know its a-essence. Jackson talks mainly about understanding the term ‘water’ rather than understanding water itself, but I take it that what he says in formal mode has an obvious counterpart in the material mode.)

Focusing then on a-revelation, we may now formulate the first premise of an argument to the conclusion that revelation—that is, c-revelation— is true of pain. If in general, understanding is knowledge of a-essence, then presumably understanding pain is knowledge of its a-essence. Hence:

  1. (8) To understand pain is know that pain is F, where F is in fact the a-essence of pain, that is, a property of pain which, in all possible worlds considered as actual, it has and nothing else does.

    (p.132) The second premise of the argument is a thesis about the a-essence and the c-essence of pain, namely that they coincide or are one and the same.

  2. (9) The a-essence of pain just is the c-essence of pain.

    From (8) and (9) we may derive the conclusion that:

  3. (10) To understand pain is to know that pain is F, where F is the c-essence of pain, that is, a property of pain which, in all possible worlds considered as counterfactual, pain has and nothing else does.

But (10) is clearly a version of revelation as we have been discussing it. In short, if (8) and (9) are true, revelation in the sense that we have been discussing follows immediately.

Since this argument is valid, its evaluation turns on the truth of the premises. We have already seen some of the motivation for (8)—but what of (9)? It is here that Kripke really comes in to play. For it is often thought that (9), or something like it, is present in Naming and Necessity. The reason for believing this emerges when we look more closely at what it is to consider a possible world as actual. If we let Kripke be our guide, to consider a possible world as actual is to imagine ourselves in a world that is epistemically and qualitatively identical to the actual world. So, for example, to ask what property water has uniquely in all possible worlds considered as actual, what we need to do is imagine ourselves in every world that is epistemically and qualitatively identical to the actual world, and ask what property water has uniquely in each such world. Analogously, to ask what property pain has uniquely in all possible worlds considered as actual, what we need to do is imagine ourselves in every world epistemically and qualitatively identical to the actual world, and ask what property pain has uniquely in each such a world. However, because a world epistemically and qualitatively identical to the actual world is a world in which pain exists, it seems natural to say that the property that pain has uniquely at all such worlds simply is pain. On the other hand, it seems equally true that in all possible worlds considered as counterfactual, the property that pain has uniquely at such worlds is that of being pain. Hence the c-essence of pain simply is its a-essence.

In sum, it appears that here we have an argument that is in a sense suggested by Kripke’s discussion, and yet also suggests that revelation is true. Have we then arrived at the thought that Kripke is relying on revelation in Naming and Necessity? Moreover, have we arrived at the thought that the conception of experience that incorporates revelation is the ordinary or natural one?

(p.133) The answer, in my view, is “no.” For even if we agree that (9) is true and that Kripke accepts it, it is not at all clear that (8) is true or that Kripke accepts it. As we noted in the previous section, when Kripke says that understanding pain is quite different from understanding heat, it is natural to view him as saying that the picture of understanding that is plausible in the case of heat, whatever that is, is not plausible in the case of pain. But this suggests that even if a-revelation or something like it is true for heat, it is not true in the case of pain. In particular, it is not the case that understanding pain is knowing that pain is F where ‘F’ expresses the a-essence of pain. Rather what is true is that understanding pain is knowing of F, that pain is it. In other words, understanding pain requires a certain sort of de re knowledge. But if this is true, Kripke is not relying on revelation of any sort: he is not relying on c-revelation, and he is not relying on a-revelation either.

We might put the point another way by saying that the argument I just considered would establish that Kripke is relying on revelation only if it could be shown that Kripke is relying on both (8) and (9). However, even if we assume that Kripke is relying on (9), it remains to be shown that he is relying on (8). Perhaps some of what Kripke says suggests that he thinks that a counterpart of (8) is true in other cases; for example, perhaps a claim like a-revelation is true in the case of heat. But his discussion of the difference between heat and pain suggests that he is not relying on a-revelation in the case of pain. But this suggests more generally that he is not relying on revelation.

14 Revelation and Conceivability

The issues about two-dimensionalism and the interpretation of Kripke that we have just been discussing are notoriously difficult. As both Chalmers and Stalnaker have recently emphasized (see Chalmers 2004; Stalnaker 2004), there are many different interpretations of the two-dimensional framework. I will not try to investigate this matter further here. However, it might be supposed that there is a more basic line of thought lying just beneath the technical detail. The more basic line of thought connects the issue about revelation that we have been discussing with the much-discussed issue of the conceivability argument against materialism.

As is well known, the conceivability argument proceeds from two premises: first, that it is conceivable that there is a world identical to the actual world in all physical respects but different from it in some experiential or (p.134) phenomenal respect; second, that if this is conceivable then it is possible. The conclusion of the argument is that physicalism is false, for physicalism—at least as we have been understanding it—entails that any world identical to the actual world in all physical respects is identical to it in all respects whatever, including phenomenal respects.

Now there are obviously a host of questions to be raised about this argument, many of which have been taken up in recent philosophy. But the line of thought I want to concentrate on begins from the observation that in advancing the conceivability argument, its proponent presumably presupposes some conception of experience or other. Which conception? Well, on the one hand, it seems reasonable to suppose that the proponent of the conceivability argument is presupposing an ordinary or natural conception. The reason for this is roughly that, whatever else is true of the conceivability argument, it is at least a fairly natural argument and one which has very widespread appeal. On the other hand, one might also think that the proponent of the conceivability argument presupposes a conception of experience that incorporates revelation. Putting these two points together, we arrive at the idea that the conception of experience which incorporates revelation is an ordinary or natural one.

As against this, however, I think we should be skeptical of the idea that the proponent of the conceivability argument is relying on revelation, and for two reasons. First, it is true that the proponent of the conceivability argument presupposes some conception of experience—but why suppose that he or she is presupposing revelation in particular? To advance the conceivability argument is simply to engage in a certain sort of reasoning about, or thought about, experience. But in general we can reason about something, and think about it quite deeply, without knowing its essence. (If we could not, then reasoning could never lead to knowledge of essence.) Why should it not be that the sort of reasoning which a proponent of the conceivability argument is engaged in is of this sort?

Second, if the proponent of the conceivability argument relies on revelation then the proponents of a number of other arguments would have to be relying on revelation too. For example, consider the perfect actor argument against behaviorism. As I understand it, the perfect actor argument proceeds from two premises: first, that it is conceivable that there is a world identical to the actual world in all behavioral respects but different from it in some experiential or phenomenal respect (a world of perfect actors); second, that if this is conceivable then it is possible. The conclusion of the (p.135) argument is that behaviorism is false, for behaviorism entails that any world identical to the actual world in all behavioral respects is identical to it in all phenomenal respects. Now, so far as I can see, the idea that the conceivability argument against materialism presupposes a conception of experience which incorporates revelation is no more and no less plausible that the related idea that the perfect actor argument against behaviorism presupposes that conception.

But this observation is devastating for the proponent of the Canberra Plan, and equivalently for option 3. For recall that the proponent of the Canberra Plan is suggesting that we should reject the conception of experience that incorporates revelation. If that conception is being presupposed in the perfect actor argument, then presumably that argument too should be rejected. But here we have reached bedrock: for the perfect actor argument should not be rejected. (At any rate, nobody rejects it. At any rate, it is assumed to be sound by most people who teach and think about philosophy of mind.) But if it is not to be rejected, it is not to be rejected because it presupposes a conception of experience that incorporates revelation. (For further discussion of the comparison between the conceivability argument against materialism and the perfect actor argument against behaviorism, see Stoljar 2005, 2006a,b.)

15 Conclusions

I began with some notes on a certain program in philosophy, the Canberra Plan. What I have been doing is criticizing the plan by considering one piece of philosophy in which it is instantiated: Lewis’s suggestion that, since revelation is built into folk psychology, we need to replace the ordinary conception of experience with a revised conception. My discussion has fallen naturally into three parts:

In the first part, sections 2 to 7, I set out what I take to be the thesis of revelation, emphasizing that revelation is best seen as a principle about what happens when you understand, for example, experiences, as opposed to what happens when you have experiences.

In the second part, sections 8 and 9, I distinguished two ways of responding to the argument from revelation against physicalism, and suggested that the distinction between them boils down to whether the conception of experience that incorporates revelation is in any sense a natural or central one. If it is not, then one may reject the argument as starting from a conception of experience that we have no need to respect.

(p.136) In the third part, sections 10 to 14, I considered a number of reasons for supposing that the conception of experience which incorporates revelation is a natural or central one, many of which I extracted from Lewis’s discussion of these matters: the idea that it is part of folk psychology, the idea that it is obvious, the idea that is presupposed in Kripke’s discussion of heat and pain, the idea that it is part of two-dimensionalism, and the idea that it is presupposed in the conceivability argument. In my view the suggestions prove to be unpersuasive. The conclusion to be drawn therefore is that response 2 rather than response 3 is the correct response to the argument from revelation: we are free to reject the argument as being driven by a conception of experience that we have no reason to endorse. Pain may be different from heat, but that does not make it similar to the part–whole relation.

What do these points tell us, if anything, about the general status of the program of the Canberra Plan? Well, one thing they tell us is that one motivation for a particular instance of the Plan is misguided. If the source of the conflict between experience and physicalism is revelation, then in my view there is no conflict. And, if there is no conflict, there is no motivation emanating from this argument to articulate a replacement conception of experience.

However, lying behind the topic of revelation that I have been concentrating on is a second, much larger, issue about the extent to which one philosophical problem can be treated as a template for another. At the beginning of the essay, I briefly considered a suggestion of Huw Price, that the proponents of the Canberra Plan assume an overly uniform conception of assertion. Price’s idea is to be criticized, I said, on the ground that it assumed that philosophical problems are in a certain sense all of a piece. But proponents of the Canberra Plan, just as much as Price, are vulnerable to that sort of point. Both Price and the Planners assume that philosophical problems exhibit some sort of deep similarity, and that in consequence there are meaningful generalizations that can be made about the origins of these problems and how to solve them. But what is the rationale behind this assumption? Of course it is useful to compare and contrast, but the idea that there is or should be some sort of structure for philosophical problems seems to me to be quite unlikely and at any rate is has not been argued. So we might suggest that what goes wrong in the Canberra Plan is not, as Price suggests, that it assumes an overly uniform conception of assertion; what goes wrong is that it assumes an overly uniform conception of philosophical problems.

(p.137) Acknowledgments

I presented previous versions of this paper to audiences at the University of Aarhus and the Australian National University. I am very much indebted to the very good comments I received at both places. For further comments and discussion, I am greatly indebted to: David Chalmers, Christopher Daly, Nic Damnjanovic, Jakob Hohwy, Adam Pautz, and Derk Pereboom. (p.138)