Subjective Physical Facts

By Max Deutsch (Rutgers University)

Physicalism is, minimally, a thesis concerning the nature of the mental. Physicalists are at least committed to there being a dependence relation of some variety holding between the mental facts and the physical facts. Sometimes the thesis is construed more broadly than this, making physicalism a stronger thesis. This broader construal takes physicalism to say something about the totality of facts: that the physical facts are the facts simpliciter or that the fixing of the physical facts would leave nothing left to be fixed.

Of course, if one believes that the totality of facts is exhausted by the physical facts conjoined with the mental facts, then the weak and strong versions of physicalism collapse into one. But I think that there are pretty good reasons not to believe that. In any case, what concerns me here is an anti-physicalist argument which, if successful, falsifies the weaker thesis, the thesis asserting the dependence of the mental on the physical. Since any argument which falsifies the weaker thesis suffices to falsify the stronger thesis, it does not matter for my purposes which brand of physicalism, if either, one subscribes to.

Physicalism of both varieties is allegedly defeated by the truism that one cannot know what it is like to experience something unless one has had experiences of the type ordinarily produced by that something. The allegation is surprising, but what is more surprising is that it appears to be supported by an extremely simple and compelling argument. The argument is the so-called ‘knowledge argument’ made famous by Frank Jackson in his ‘Epiphenomenal Qualia’.

The purpose of this paper is to demonstrate that the knowledge argument is flawed. Other philosophers have attempted this before but I think that most of these other attempts have failed. And, while the main idea behind the strategy I employ is not new, certain details are new, and it is an idea that has not received the attention it deserves.

I claim that the knowledge argument is unsound, that one of its premises is false. But the premise I criticize is not one typically criticized by other physicalists and the falsity of the premise I criticize has, I think, an interesting implication for the way in which physicalism should be thought of. What I think the knowledge argument shows is that physicalists must accept that there are subjective physical facts. What, exactly, I mean by that will be apparent presently; first, a presentation of the knowledge argument.

Jackson’s knowledge argument involves a character named Mary who has been confined, since birth, to a black-and-white room. Mary has been given a scientific education, but what she has learned has been learned through black-and-white books, and lectures transmitted to her room via a black-and-white monitor. The argument proceeds as follows.

Most of the physicalist responses to this argument of which I am aware reject (2). The most popular way to reject it is to claim that Mary does not learn a new fact when she is released, she merely gains a new "mode of presentation" for a fact she already knew. The idea is that there are the facts, on the one hand, and "ways of thinking" about them (i.e modes of presentation) on the other. The relationship between a given fact and the ways of thinking about that fact is one-many; there are numerous modes for each fact. This requires a "coarse-grained" individuation of the facts: Facts are taken, in basic cases, to be the having of a particular property by a particular object. The sentences ‘The morning star is much discussed’ and ‘The evening star is much discussed’ attribute the same property to the same object and thus they correspond to the same fact. But to think the thought expressed by the former is to think something different from the thought expressed by the latter. Here, then, is an example of a single fact with two different associated modes of presentation.

The lesson, according to those who favor the mode of presentation response to the knowledge argument, is that it is possible that Mary’s pre-release education has put her in touch with all the facts, all of the object/property pairs that are relevant to color and color vision. To accommodate the intuition that she learns something new when released, the strategy is simply to take this to be the acquisition of a new way of thinking about one of those already encountered objects or properties

There are many problems with this response and those of its general sort, the primary one being that gaining a new mode of presentation for a fact already known just is learning a new a fact. By gaining a new mode of presentation, Mary not only learns that a certain fact is known by her "under" this new mode of presentation, but she learns also that two modes of presentation now possessed by her, one old and one new, are modes of presentation of a single fact. Mary, if you like, learns new facts about the old facts. So, admitting that Mary gains a new mode of presentation for a fact she already knew is admitting that Mary comes to know new facts, facts which involve modes of presentation. But if she knew all of the relevant physical facts before her release, then this new fact cannot be a physical fact.

An early criticism of ‘type-type’ mind/brain identity claims runs like this: Mental states cannot be identical to brain states because one can know that one is in a particular mental state, a state of pain, say, without knowing that one is in whatever brain state alleged by the identity theorist to be identical to pain. The reasoning behind the criticism is fallacious. If it were not, then we could conclude that water is not H2O, that Hesperus is not Phosphorus, etc., via the same sort of reasoning. Those physicalists who object to (2) by invoking the mode of presentation response sketched above accuse the knowledge argument of the same sort of fallacy, a fallacy that does not appear so only if one fails to countenance the intensionality of ‘knows that’ contexts.

The accusation is unfounded. The difference between the fallacious argument concerning mind/brain identities and the knowledge argument is that the latter assumes that the physicalist will admit that the knowledge Mary acquires in her room is exhaustive. If one is a physicalist, one cannot avoid taking this assumption to be implied by (1). Mary, by knowing all the physical facts about color and color vision, is supposed to know all that there is to know about color and color vision. Now, presumably, that ‘what it is like to see red’ and some expression couched in the language of neurophysiology both pick out the same thing, namely an experience of a certain type, is one of the things that there is to know about color and color vision. But Mary, locked in her room, does not know it. The anti-physicalist conclusion follows immediately.

The intensionality of knowledge will not help here. If you know everything there is to know about water, you know that ‘H2O’ refers to water, and you know that ‘H2O is wet’ expresses a mode of presentation that presents the fact that water is wet. If you know everything there is to know about Clark Kent, you know that he is Superman and that the mode of presentation expressed by ‘Clark Kent can fly’ and that expressed by ‘Superman can fly’ are modes of presentation of the same fact. Similarly, if knowing all the physical facts about color and color vision is all that there is to know about that, then Mary should know what it is like to see red, even if ‘what it is like to see red’ is taken to be merely a mode of presentation involving fact. (Since, according to the mode of presentation response, there are no new facts that do not involve modes of presentation for Mary to learn.) So much the worse for the mode of presentation response.

Another way to reject (2) is to claim that while Mary does indeed learn or gain something upon being released and seeing red for the first time, what she learns or gains is not factual knowledge, not knowledge that . Instead, she gains an ability; she learns how, for example, to imagine (visualize) experiences of red and to remember and recognize red experiences. But no new facts are learned. The facts are one and all physical, and Mary was possessed of all the physical facts prior to her release.

The trouble with this response is that while it is perhaps true that Mary gains abilities and that her gaining them cannot be construed as merely acquiring new factual knowledge, it seems clear that Mary also gains new factual knowledge. She could, if she took the trouble, express this new knowledge via a tell-tale ‘that-clause’: "Ah ha!," she could say at that first confrontation, "I now know that this is what it is like to see red."

This is not to claim that the acquisition of abilities, mental or otherwise, is necessarily accompanied by the acquisition of factual knowledge. There are perhaps examples of learning-how that are not, or at least not clearly, examples of learning-that (think of the abilities acquired by creatures low on the cognitive totem pole). The claim is rather that in Mary’s case it is unintuitive to suppose that it is abilities and abilities only that she gains. Perhaps creatures who lack certain conceptual capacities do not learn that anything is the case when they see red for the first time. But Mary, conceptually sophisticated as she is, is able to formulate a belief based on her first encounter with red, a fully propositional, truth-evaluable belief. A belief that corresponds to a fact.

Furthermore, in Mary’s case, it does seem that new factual knowledge is in some sense necessarily consequent on her gaining the abilities she is said by the ability response to gain. Mary, being a normal human being and thus relatively conceptually sophisticated, can "propositionalize" the know-how she acquires. She could say, and say truly, "This is how one goes about imagining red" or "To recognize red is to experience things thusly". Were she to say these things she would be expressing facts, facts she could not have known before her encounter with red.

These considerations are meant to show that Mary’s acquisition of various abilities cannot be the whole story regarding what happens to her upon her release from the black and white room. She learns more than how to do various things, she also learns that certain things are the case. But there is another sort of criticism of the ability response, one that is equally damaging. The criticism is this: Mary could learn what it is like to see red without gaining any of the abilities proponents of the ability response claim she must. Mary might be cognitively impaired. She may lack the capacities to imagine, remember, or recognize. She could, despite these limitations, come to know what it is like to see red, if only briefly. She could say, while looking at that red something, "So this is what it is like to see red", and she could say this truly even if her impairments prevented her from being able to later imagine, remember, or recognize her experience. This possibility shows that the possession of various abilities is not necessary for knowing what it is like to see red.

I conclude that the intuition that Mary would learn something new, that she would gain new factual information, is strong, too strong to deny. Rejecting (2), in the ways mentioned, or in any other way, requires one to deny it. That is trouble with such rejections.

I think that physicalists should reject (1). They should deny that it is possible for Mary to know all of the physical facts while confined to her room. Or rather, more precisely, they should admit that having experiences is necessary for learning a certain class of physical facts—the subjective physical facts.

The distinction between the objective and the subjective has been put to many uses in various areas of philosophy. Indeed, so many, that it is somewhat inappropriate to speak of the distinction between the objective and the subjective; there are many such distinctions. The subjective/objective distinction that is relevant to the knowledge argument is, of course, one that takes subjectivity and objectivity to apply, whether derivatively or originally, to facts, but this does not help much; there are various senses in which a fact may be said to be subjective or objective.

Sometimes what is meant, at least in part, by saying that a fact is subjective is that it is non-physical. Obviously, this is not what I mean. Since I hold that there are subjective physical facts, I clearly cannot also hold that physical facts are, by definition or for any other reason, necessarily objective. But the conviction that the physical facts must be objective, is a conviction held by physicalists and anti-physicalists alike. This conviction is the ultimate source of the physicalist’s worry over the knowledge argument, just as it is the source of the anti-physicalist’s confidence in the power and success of the argument. To show that the conviction is false, I propose to give a sense to ‘subjective fact’ and a sense to ‘physical fact’ such that those senses capture something intuitive about what it is for a fact to be subjective and what it is for a fact to be physical, and it is possible that there are facts which are both subjective and physical in the proposed senses. That there are those who hold, as matter of what is analytically the case, that there can be no subjective physical facts does not trouble me. They have their definitions wrong.

Perhaps the most standard characterization of the subjective/objective distinction is one that takes it to be co-extensive with the distinction between mind-dependence and mind-independence. According to this characterization, the fact that Mary learns when released from her room (that this is what it is like to see red) surely counts as subjective, but then many of the facts that Mary learns while confined are surely subjective as well. When Mary, while confined, learns various facts couched in the language of neurophysiology, she is learning facts concerning the properties of her mind, and those facts are, in that way, mind-dependent. So, the distinction between mind-dependency and mind-independency is not relevant. We need a distinction that sets the facts Mary learns while confined apart from those that she learns when released.

So what, then, is the relevant subjective/objective distinction? There is an intuitive sense in which to say that a fact is subjective is to comment on the epistemological status of the fact said to be so. Subjective facts are knowable only in a certain way, or from a certain perspective. The case in point of course is the case of phenomenal facts, facts about what it is like to experience something or other. I claim that such facts are knowable only to those capable of having the experiences in question, and knowable to those capable of having the experiences in question only by having them. The contrast, then, is that objective facts are knowable in many ways, or from many points of view. Take an ordinary, uncontroversial example of an objective fact; the fact that water is clear, say. One can come to know this fact in a variety of ways. One can read it in a trustworthy book, or hear it proclaimed by trustworthy proclaimant, or go out and look at some samples of water with one’s trustworthy eyes. That water is clear is many-ways knowable. Knowing what it is like to see red, on the other hand, is one-way knowable. One can know what it is like to see red only by having experiences of the type ordinarily produced by seeing red. This is what the subjectivity of such facts consists in.

I assume that the claim that facts about what it is like to have various experiences are subjective facts is a claim that those who take the knowledge argument to be valid are likely to accept. After all, as I mentioned at the outset, the thought that knowing what it is like to have a certain experience takes having that experience is the thought that gets the knowledge argument so quickly up and running. Those physicalists who respond to the knowledge argument by rejecting (2) (while accepting (1)), however, are likely to balk. Indeed, such physicalists are forced to deny that phenomenal facts are subjective. This is because subjectivity, in the sense of one-way knowability, is an individuating feature of subjective facts. That is, no two sentences, one of which expresses a subjective fact, the other of which expresses an objective fact, could express the same fact. Since, as we have seen, rejecting (2) via the mode-of-presentation response or via the ability response requires one to deny that the facts Mary learns when released possess individuating features not possessed by any of the facts she learns prior to her release, such rejections require one to deny that Mary, when released, learns subjective facts. So, we see that such rejections are not merely subtle tinkerings with the meaning of "learns a new fact"; they force one to deny that one can learn what it is like to see red only by having experiences as of seeing red. But, then, as I claimed at the very beginning, they are forced to deny something that is not merely true, they are forced into a denial of a truism.

Physicalism, as I have said, is, minimally, the thesis that the mental facts depend on the physical facts. Since there are a variety of dependence relations that could plausibly be taken to hold between the mental facts and the physical facts, minimal physicalism comes in a variety of flavors. But it is generally agreed that minimal physicalism is, minimally, a supervenience thesis: It is impossible that there be a difference in the mental facts without some difference in the physical facts. This tells us the general kind of dependence to which physicalists are committed but it tells us nothing about what it means to say that a fact is physical. A lot of energy has been spent trying to specify which of the many varieties of supervenience is best suited to capture physicalist intuitions. And, indeed, there is something of a consensus now to the effect that if one is a physicalist, one is committed to the global, logical supervenience of the mental facts on the physical facts. Less energy has been spent on what one would think would be the prior project of trying to give a precise meaning to ‘physical fact’. In part, this is due to the difficulty of the project, a difficulty that is shared with just about every definition-giving project wherein the term being clarified is metaphysically fundamental. But I suspect that it is due also, in some measure, to a worry, on the part of those who feel inclined towards physicalism, about opening physicalism to easy counterexample and an eagerness, on the part of those not so inclined, to start cranking those counterexamples out. In my view, the knowledge argument along with the standard responses to it are born of a vague and probably incorrect characterization of what it is to be a physical fact, a characterization that I will soon criticize. But first, I will try myself to give as precise a content I can to ‘physical fact’.

I take it, and I take it that most others implicitly take it, that physicalism is, at bottom, an ontological doctrine. It is a doctrine about the kinds, in a very basic sense of ‘kinds’, of stuff that there are in the world. The trick, then, is to give an illuminating specification of which kind of stuff the physical stuff is. A specification that tells us that the physical stuff consists of physical objects and physical properties (and, correspondingly, that physical facts are facts which involve physical objects and properties) is correct, but obviously not illuminating; What is a physical object or property? Fortunately, there are uncontested examples of physical objects and properties, things to which we can actually point.

When one is trying to describe a general sort of thing, having instances of that sort of thing that one can pick out via ostension is always helpful. Indeed, it often suffices, when trying to describe or define what sort of something a particular something is, to point at an instance of that something and say, "That is what such somethings are." I suggest that we use this method to define ‘physical’. Pick your favorite, uncontroversially physical object. Point at it. Now say, "To be a physical object is to bear the same ontological type of object relation to this thing [the thing at which you are pointing]." Now pick your favorite, uncontroversially physical property. Point at it. (It has to be an instantiated physical property of course.) Well, you get the idea. The definition of ‘physical fact’ now drops out of the ostensive definitions of ‘physical object’ and ‘physical property’: the physical facts are those which involve only those objects which bear the same ontological type of object relation to this object (my toaster, say) and those properties which bear the same ontological type of property relation to that property (the property of being made of metal, say).

Obviously, there is a remaining question concerning the definition just given; a question about the similarity relations utilized in giving it. We understand the definition only insofar as we understand what sameness of ontological type comes to. But I think that partial understanding here is enough. Enough, at least, to count those who had no idea what physical facts were before being given the definition, as now, after being given the definition, possessing the concept physical fact.

By analogy, it is possible to get someone, a child say, to understand what dogs are, to get them into possession of the concept dog, by pointing out instances of dogs. It is possible to do this even though the child may have only a very vague idea of what counts as the same type of animal relation. That we all, perhaps, have only a vague understanding of what it is for something to belong to the same ontological type as something else does not prevent us from acquiring the concept physical object by means of that vague understanding.

One could supplement the proposed definition by trying to say more about what makes for sameness or difference of ontological type. For example, it has been claimed that causation is the crucial notion when it comes to distinguishing ontological types: Two things are of the same ontological type if, and only if, they can stand in causal relations to one another. Or, again, it has been claimed, famously, that the notion of spatiality is crucial: two things differ in ontological type if, and only if, one has a location in space and the other does not.

As I say, one could fill out the proposed definition in these ways. I do not myself, because I think, first, that the unfilled-out definition suffices; second, that the suggested fillings-out are not clearly true; and third, my primary aim in suggesting a definition of ‘physical fact’ is simply to give a flavor for the kind of definition that I favor, a kind that stresses the ontological point behind calling a fact ‘physical’.

It should be clear by now what I mean when I claim that the phenomenal facts that Mary learns when released are subjective physical facts. I mean, on the one hand, that those facts are one-way knowable, knowable only by having experiences. And, I mean, on the other hand, that the objects and properties involved in those facts bear the same ontological type relation to the objects and properties involved in an "ordinary", uncontroversially physical fact. That the phenomenal facts Mary learns are subjective and physical counts against premise (1) of the knowledge argument: It is not possible for confined Mary to learn all of the physical facts concerning color and color vision because some of those facts are subjective.

Call the conception of the physical facts laid out above the ‘ontological’ conception of physical facts. Many discussions of physicalism, both pro and con, utilize a different conception, one that can be usefully labeled ‘the language of science’ conception of physical facts. According to the language of science conception, the physical facts are, or are entailed by, those facts expressible in a certain vocabulary—the vocabulary of physics. It is this conception of the physical facts that I alluded to above, and criticized as vague and probably incorrect. I will now try to substantiate these criticisms.

It seems rather optimistic to suppose that the language of current physics has the expressive power to capture all of the physical facts. So, the characterization must be amended to allow for the possibility that new terms may have to be added to the current vocabulary in order to ensure that some of the as yet unknown physical facts are at least entailed by the facts expressible in that vocabulary. But how should it be amended? I suggest that there is no clearly correct answer to this question, no clearly statable relation that the new vocabulary must bear to the old. That there is no answer to this question is what I mean when I say that the language of science conception is vague.

But even if there were such a relation, the language of science notion of ‘physical fact’ would not be clearly correct. This is because the language of current physics as well as the suitably related language of future physics are presumably both objective languages. That is, they express, or will express, only objective facts. That scientific languages express only objective facts is, indeed, taken to be one of their primary virtues. So, the language of science notion of ‘physical fact’ is a notion that recognizes only facts that are themselves objective, or are entailed by the objective facts.

We must ask, then, whether it is possible for objective facts to entail subjective facts since, as I have argued, the phenomenal facts are subjective. I am inclined to think that the answer to this question is ‘no’. But if this is right, then the conception of facts that are physical in the language of science sense will not cover the phenomenal facts, facts about what it is like to experience something or other. This appears to be the fundamental flaw in the conception of a fact that is physical in the language of science sense.

To bring this flaw into clearer focus, we should consider, once more, the functioning of the knowledge argument. Clearly, the conclusion that the knowledge argument apparently reaches—that there are facts about the properties of minds that are not physical facts—will vary in meaning and importance depending on what conception of physical facts is being assumed. The same is true, of course, of the meaning and importance of the thesis of physicalism. Suppose, then, that we assume the language of science conception of physical facts. Physicalism, under this assumption, becomes the thesis that the mental facts supervene on those facts expressible in the vocabulary of current physics, or some suitable extension thereof. And, the anti-physicalist conclusion apparently reached by the knowledge argument becomes the conclusion that there are some mental facts which do not supervene on facts that are expressible in that way.

I think it is fairly clear that the knowledge argument does reach this conclusion given our assumption about the meaning of ‘physical fact’. Since, in assuming the language of science conception, we are taking the physical facts to be, one and all, objective, there seems to be no way to resist the claim that it is possible for confined Mary to learn all of the physical facts concerning color and color vision. She can learn them all, presumably, by reading them in her trusty black-and-white textbooks. Since we have already seen that the standard ways of objecting to the claim that Mary gains genuinely new factual knowledge when released are failures, it appears that we are also stuck with the second premise of the knowledge argument. And, since the argument is undeniably valid, we are forced to agree to its conclusion. There are, indeed, facts about the properties of minds that are not physical. Here we come dualism!

I hope that I have already given some clue as to what I think our reaction should be to the kind of "anti-physicalism" that we have reached by using the language of science conception of physical facts as fuel for the knowledge argument. Our reaction should be: So what?! We have reached the conclusion that the language of science does not have the expressive power to capture, either directly or by entailment, all of the facts that there are concerning color and color vision. This is merely a conclusion about the semantic potential of a certain sort of vocabulary, most definitely not a conclusion about the fundamental ontological kinds that there are. It is a conclusion, furthermore, that we should have been able to reach without the help of the knowledge argument. After all, we knew already that the phenomenal facts are subjective facts, just as we knew already that the language of science is in the business of expressing only objective facts. So, the anti-physicalism that is forced upon us by assuming the language of science conception of physical facts is true, but it is harmless.

The harmful sort of anti-physicalism is the kind that you get if you assume the ontological conception of physical facts. But this sort, as I have argued, is not forced by the knowledge argument. Calling a fact ‘physical’ in the ontological sense does not require that that fact be objective. There are subjective physical facts, ones that poor Mary, locked up in her room, simply cannot know.

Subjective Physical Facts

Max Deutsch

Rutgers University

10/27/98

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