About the right version of the knowledge argument

 

The scope of this paper is to inquire about the meaning of the knowledge argument, starting from the assumption that the argument is sound. The strategy of this paper is to assume the cleanest version of the knowledge argument, a version that has already dealt with various criticism and required limitations, and then to focus on a further refinement that is not made explicit in many cases but which I think is very important and needs a clarification. My thesis is that there is only one correct version of the knowledge argument, while the usually discussed version of it is not sound. To the point, I claim that the knowledge argument is sound only if is constructed around a completely deaf person, but not if it is constructed by staring from a color-blind person.

 

Is there any clear anti-physicalist version of the knowledge argument?

 

First, we have to see if there is a sound version of the knowledge argument. In what follows I will reconstruct the knowledge argument by showing the main point against and the replies that refined it (although I will not follow a historical perspective, but a logical one). In this section, my intention is not to defend a certain version of the knowledge argument, rather to see if there is any sound version of it, and -if the answer is yes- what does it precisely claim.

The initial observation to be made is that, for Nagel, the knowledge argument was not a necessarily a priori proof that physicalism fails in explaining phenomenal information. Rather, the argument was dealing with the difficulties of the then current physicalism; these difficulties were expected to be discussed and explained by a (forthcoming) serious physicalist approach to mind.[1] As pointed out by Lewis, the physicalist’s claim is not that physicalism is necessary true but that it is contingently so. If this is the case, then an anti-physicalist argument has to deal with this contingency only and any anti-physicalist argument which is directed against physicalism as a necessary truth is misplaced, since it attributes to physicalism more than it claims.[2] However, the development of the knowledge argument transformed it into a kind of testimony that physicalism will ever be an incomplete account since it cannot offer a conceptual breakthrough that is able to accommodate knowledge of qualia within the third party’s terms.

The starting point for the knowledge argument is the intuition that “the subjective character of experience is fully comprehensible only from one point of view,” namely from the first-person perspective.[3] This means that X cannot know Y’s subjective experience but all that it is accessible to X is a description of Y’s qualia; X can either understand, imagine, or intuit what is it happening within Y, but this is not to know what Y knows when Y has a certain qualia. The easiest way to make the difference between a first-person perspective and a third person perspective is to take an example where all that is available is only the third person perspective. For Nagel, the best example is a very different being like a bat, since as humans we can know what is it to perceive through echolocation by third person perspective only. Humans cannot feel like a bat and therefore regardless of the available amount of knowledge about what it is going on within the senses of a bat we cannot know a bat’s qualia.

Maybe a clearer form of the knowledge argument is that which stresses that the impossibility of X knowing what is it like to be Y is not a proper formulation of the intuition that physicalism leaves something out. As Jackson pointed out, a successful argument against physicalism does not need to show that regardless of the information available X cannot know what it is for Y to have a certain qualia and this for two reasons. [4]

The first reason is that this contention would claim more than is required in order to displace physicalism or functionalism. All that is needed in order to disqualify them is to show that no amount of scientific information can explain a quale. The formulation ‘X cannot know what is it like to be Y’ may be misleading, because one can take it as the requirement that X shall have this knowledge from the inside of Y. But then the anti-physicalist strategy would be asking too much. Moreover, if the anti-physicalist would be objecting that X cannot know from inside Y what is it like to be Y when only the physical information is available, then the anti-physicalist strategy would not be an objection to physicalism. The rationale is that this king of requirement would ask for melting the difference between distinct beings, which would infringe the law of identity and therefore would be absurd.[5]

The second reason is that in order to ask about the difference in knowledge between X (which has no experience of p) and Y (which has experience of p) there should be a difference between X had experienced p and X hadn’t experienced p. If there were no difference for X whether X had experienced p or not, then to claim that ‘X cannot know what it is like for Y to feel p’ would be a futile charge against physicalism. For example, in a world of zombies (wherein, ex hypothesi, there is no qualia), where it is no difference between X had experienced p and X hadn’t experienced p, to claim that ‘X cannot know what it is like for Y to taste chocolate’ would be pointless. Therefore, it should be firstly proved that there is a difference in knowledge between X that hadn’t experienced p and X that had experienced p in order to talk about the difference in knowledge between X that hadn’t experienced p and Y that had experienced p. It is a logical requirement that it should make a difference within the first person perspective if one has an experience of p or not in order to discuss about any difference between the first person perspective and the third person perspective. Nevertheless, what it is at stake is exactly if there is a difference between having qualia or not. Accordingly, the knowledge argument must leave aside the charge that ‘X cannot know what it is like to be Y’ in order to avoid unwanted misunderstandings or any reply that it begs the question in its favor. The knowledge argument has to be formulated at a basic logical level if it is to be seen as an argument that accurately establishes that physicalism leaves something out.

As a result, the proper knowledge argument shall be formulated within the framework of a first-person perspective. That is, it points out that there is a difference in knowledge between X that hadn’t experienced p and X that had experienced p. The standard formulation is that X cannot find out what is it like to have the K-qualia by any kind or amount of scientific (or, less demanding, conceptual) knowledge.[6] The usual example is that of a scientist which, despite her complete scientific knowledge about the psycho-physical processes that accompanies a certain kind of experience in a human, still cannot know what is it like to have that experience until she experience it.[7] If the argument is valid, then it can be claimed that physicalism is incomplete.

One proposed form of the argument was the following:[8]

 

1.      Deaf Mary (before taking off the earplugs) knows everything physical there is to know about other people that hear.

2.      Deaf Mary (before taking off the earplugs) does no know everything there is to know about other people that hear (because she learns something about them only upon unplugging her ears).

ð 3. There are truths about other people (and herself) which escape the physicalist story.

 

The problem encountered by this form of the knowledge argument is that it proves nothing, since it is constructed upon an equivocation on ‘knowing’ in the premises. Specifically, in the first premise ‘knowing’ refers to its propositional content, while in the second premise ‘knowing’ refers to its mode of acquiring. Therefore, the conjunction of 1 and 2 cannot imply 3.[9]

Another form of the argument avoids the charge of equivocation:[10]

 

1.      Deaf Mary (before taking off the earplugs) knows everything which can in principle be expressed in the vocabulary of physical science about hearing.

2.      Deaf Mary (before taking off the earplugs) does not know the phenomenal nature of the sound.

ð 3. The phenomenal nature of sound in principle cannot be characterized using the vocabulary of physical science.

 

Since the argument is now formally valid, the only defensive strategy for a physicalist or a functionalist is to repudiate one of the premises and declare that, in fact, it is unreasonable to take it as true. One can deny the first premise, by maintaining that Mary’s physical (or functional) knowledge might be incomplete. Nevertheless, this reply misses completely the point, since at stake is not the actual completeness of physical or functional knowledge, but its capacity to deliver the needed knowledge of K-qualia.[11] For Harman, this incompleteness of deaf Mary’s knowledge points that she shall know both the concept of sound-related qualia and the functional role of this concept in order to claim that she knows everything that it is to know via third person expressible knowledge. The objection goes that the first premise of the knowledge argument disregards that a deaf-born person ‘does not know all the functional facts since she does not know how the concept [of what it is like to hear] functions with respect to the perception of [sounds]’.[12] I distinguish here two separate claims; the first is that she does not know how the concept of ‘what it is like to hear’ functions when one hears something,[13] while the second is that she does not have the concept of ‘what it is like to hear.’[14] To the first aspect I respond that there is no reason why she should not be able to know how the concept functions within those who are able to hear. If functionalism is right, then functionalism shall be expressible in third person’s terms without problem. As a consequence, deaf Mary can learn all the functional details about human mind that can be in principle expressed by third person’s functional knowledge. The first premise of the knowledge argument can easily accommodate this requirement, and if this is Harman’s objection, then the reply must be that he fails to grasp the claim since the (attainable) completeness of the available knowledge was not debated. To the second aspect of the incompleteness charge against the first premise of the knowledge argument, namely that deaf Mary misses the concept of ‘what it is like to hear’, can be interpreted in two ways. If she misses the concept just because the provided knowledge about functionalism is not thorough, then this charge reduces to the above one and therefore does not affect premise 1. If she misses the concept just because the functional knowledge (expressible in third person’s terms) is not enough for knowing the hearing-related qualia, then this is not an objection to premise 1.

Still, one can reply that premise 1 has no force since no one can have all the required knowledge in one’s life. More precisely, even if physicalism would leave nothing out, the way that the knowledge argument is constructed, would still invalidate physicalism. Take the example of the zombie world. In that world, everything is in principle expressible within physicalist language and the physicalist science is complete ex hypothesi. Nevertheless, since any mind has limited resources, then no one in the zombie world would be able to know what premise 1 requires one to know, i.e. no one ever would know everything which can in principle be expressed in the vocabulary of physical science. Due to this impossible complete apprehension, anyone will be unable to maintain that one’s knowledge entitles one to claim that there is nothing left out by the physical knowledge. It follows that this form of the knowledge argument would still imply that one cannot in principle know qualia but through experience and therefore qualia are left out by the physicalist story. This is absurd, given that it was stipulated that there are no qualia. Robinson`s answer to this objection is that this is not the point of the argument, since the knowledge argument points towards what can be in principle explained by physicalism, and not towards one’s capacities to learn. In order to avoid this kind of misunderstanding, we can reformulate the first premise as Robinson recommends. 

 

1’. Take any possible set of hearing-related facts of the sort in principle expressible in the vocabulary of physical science such that the facts in that set could be known, at one time, by a given subject, and suppose deaf Mary to possess knowledge of that set.[15]

 

However, at this point one may still reject the first premise on the ground that it does not reflect physicalism’s stance. As Nigel maintains, it is impossible to understand the physical science’s concepts through lectures only.[16] To the point, it is false that deaf Mary can know all that she is required to know, i.e. premise 1’ begs the question in favor of anti-physicalism. This position is different from the above mentioned one, in the sense that it does not dig into the limited learning capacity of deaf Mary. It might be agreed that she has no problem in knowing any possible set (or even all the sets) of hearing-related facts expressible in the vocabulary of physical science. Nigel’s position is that the knowledge provided by physical science can be fully and adequately comprehended (as it is required by the knowledge argument) only by one that has the ‘relevant experiences’ that enable one to do so. Consequently,  the knowledge argument fights not with physicalism but with a distorted image about physicalism, and therefore it is due to fail as a serious objection to it.[17] To this, my first retort is that it is a very strange position to maintain that scientific knowledge that is fully expressible in a third person terms still requires the first person perspective in order to be understood. It seems that Nigel is defending physicalism either by denying it or by conflating it to the point that the anti-physicalist position is taken to be rather a part of the physicalist story. Further, I think that if Nigel would be right in claiming that physicalism is misrepresented by the first premise of the knowledge argument, even then he would still not be in the position to insist that the knowledge argument is due to fail. The detail is that the knowledge argument emphasized that qualia are not to be known otherwise but from the first person perspective, and that physicalism can not explain why it is so. Yet, one can object that my argument is void, since his claim was that qualia are an essential prerequisite for physicalism. Nevertheless, the problem with physicalism, which is under knowledge argument’s focus, is that the first person’s knowledge is in principle untransmissible in the third person’s concepts. This difficulty should be still troublesome for physicalism, even if a basic requirement would be that one should have the corresponding qualia if one is to understand physical science. In order to avoid such a misunderstanding, I propose to reformulate once more the first premise of the knowledge argument as follows:

 

1’’. Take any possible set of hearing-related facts of the sort in principle expressible in the third party’s vocabulary of physical science such that the facts in that set could be known, at one time, by a given subject, and suppose deaf Mary to possess knowledge of that set.

 

The second premise was challenged, too. The first way to challenge it is to maintain that what deaf Mary misses is not some new information (either phenomenal or physical), but a certain ability. For Lewis, the second premise expresses the hypothesis of phenomenal information, which claims that there is some independent and irreducible different kind of information that can be accessed only by experience. If it would make a difference for phenomenal information what kind of physical information is presented to one, then phenomenal information would be mappable into the physical information.[18] It follows that there can be phenomenal differences without physical difference and vice versa. Hence, the advocate of the phenomenal information hypothesis has to admit that, if the physical world had been completely different, phenomenal information could have been unchanged for deaf Mary.[19] Which is counter-intuitive. This also means that the anti-physicalist would claim more than she needs in order to make her point. To the point, all that the advocate of K-qualia needs to say is that there is some non-physical stuff within experience, and not that all the experience is non-physical. Since this is all that the advocate of K-qualia wants to say, and since the hypothesis of phenomenal information is unnecessarily strong and runs into counter-intuitive positions, the only way is to interpret the second premise as the hypothesis of acquired ability. According to the hypothesis of acquired ability, what Mary acquires when her ears are unplugged is not new knowledge that but knowledge how. However, in this case the knowledge argument does not invalidates physicalism (3 does not follow from the premises).

Robinson resists this reinterpretation of the second premise by stating that the acquired ability theory cannot overlook the phenomenal information hypothesis without being circular. The idea that one can acquire an ability to react to certain inputs has a behaviorist theory of mind flavor, and the general feature of this kind of theory is that it offers explanation from third person perspective. Nevertheless, we understand third person perspective explanations because we rely on our first person perspective, namely that phenomenal information hypothesis cannot be excluded by the ability theory. If there is no first person perspective to give meaning to the third-person perspective reports, then third person concepts lack meaning because they are nothing else but a regress. To illustrate, if one has to understand ‘disposition’ disregarding the first-person perspective, then one has to understand disposition in terms of disposition (since the unreduced first-person perspective is neglected or explained exclusively in third-persons perspective terms).[20]

If this is the case with understanding ‘disposition’, then the following problem is facing the functionalist. For the functionalist, phenomenal information reduces to ‘ability’, while ‘ability’ is nothing else but a disposition to react in a certain way to certain happenings. Further, the functionalist’s claim is that to analyze mental states through dispositional terms does not imply circularity. One way to accuse the functionalist of circularity is to observe that if everything that is mental is reduced to dispositions, then the concept ‘disposition’ shall be understood in dispositional terms as well at the end of the day. However, the functionalist can stand firm before this accusation and maintain that this is not so because when she claims that ‘understanding a mental concept means to have some dispositions’ she does not reduce the mental concept to dispositions, but only the process of understanding is reduced to dispositions.[21] In this case, something remains which is unreduced to dispositions. The remaining unreduced concepts (like ‘body’) are not under the spell of phenomenal information. Therefore, the above charge of circularity does not apply, since ‘disposition’ can eventually be understood otherwise than in dispositional terms, and these other than dispositional terms are neither dispositional not phenomenal. At this point, Robinson rejoins that the cognitive state’s essence is its content, and therefore one cannot reduce understanding to dispositional terms without reducing understanding the mental concept to dispositions as well.[22] Specifically, the functionalist maintains that:

‘Understanding what is it to have a certain disposition is sufficient for, and does not presuppose, understanding understanding a concept’.

‘Understanding understanding a concept does not conceptually presuppose understanding that concept’.

ð‘Understanding what is it to have a certain disposition is sufficient for, and does not conceptually presuppose, understanding a concept’.

Robinson argues that the conclusion cannot be sustained, because this would mean that ‘understanding what it is to have a certain disposition is sufficient for, and does not conceptually presuppose, understanding the concept of body’ should be true. However, the contrary is true: namely, the term ‘disposition’ is meaningful only in virtue of a prior understanding of the term ‘body’.[23] If so, then the functionalist is bound to recognize that an explanation given in the third person’s terms gains meaning due to the apprehension of the basic terms within the first person’s perspective. To sum up, either the functionalist acknowledges that functional terms are not reducing the phenomenal ones, or she rejects this suggestion and commits herself to the regress of understanding dispositions in terms of dispositions.[24]

Another challenge to the second premise concedes that what deaf Mary misses is more than the absence of some knowledge how: it is accepted that what she misses is properly knowledge about something. However, it is claimed that if to have K-qualia means to have information that is not expressible in physical terms, then it does not automatically follow that physicalism leaves something essential out. On the contrary, physicalism leaves nothing out and the knowledge provided by it is enough for knowing K-qualia. What deaf Mary misses is mere knowledge about new subtler ways to represent already known facts. When Mary finally hears, she acquires neither a skill, nor a non-physical or physical knowledge, but a better and more direct way of discriminating within the body of already known information. To put this objection into proprietary terminology, the removal of earplugs gives deaf Mary knowledge about actual and possible re-arrangements and new connections within the already possessed coarse information. In this case, the second premise reduces to the claim that deaf Mary didn’t know in a finer grain way what she had already known.[25]

This proposal that knowing K-qualia is nothing more than a finer grain way of discriminating between already known (physical) information should not be confounded with a finer physical information. It is so due to the fact that the proponent of this view had already agreed that all possible physical information was at deaf Mary’s disposal before she knew what it is like to hear. To say that the finer grain way of discriminating means a finer physical information would be par to say that not all the possible physical information was at deaf Mary’s disposal. Nevertheless, this would be a misinterpretation of the presented suggestion, since the proponent of this view claims that deaf Mary has at her disposal the finest possible grain physical information. To compare, the suggestion is that to acquire this finer grain way of discriminating means that one is becoming aware that one can make new (and maybe unexpected and unforeseen) connections between already known facts. To use Lycan’s words, to acquire a finer grain way of discriminating is to acquire computational information: the information that the already possessed knowledge can be computed in a different and finer way than before.[26]

According to this suggestion, knowledge argument’s premise 2 can be interpreted either as:

 

2’. Deaf Mary (before taking off the earplugs) does not know in a finer grain way the sound-related physical information she already has about herself and others.

 

Or as:

 

2’’. Deaf Mary (before taking off the earplugs) does not know in a finer grain way the sound-related physical information she already has about herself.

 

Hershfield observes that 2’ is unreasonable and seems to be self-contradictory. Even if deaf Mary didn’t know what it is like to hear before unplugging her ears, she must had knew that for others ‘what it is like to hear’ is a mere finer grain way of discriminating. There is no reason to suppose that she didn’t know the finer grain way of discriminating that was available to others since this information about others is not phenomenal. It means that Mary acquires nothing new about others, which was not already within her knowledge, when she unplugs her ears. This is contradictory with the claim that deaf Mary does acquire a new finer grain information about others.[27]

What is left is therefore 2’’. 2’’ maintains that to know in a finer grain way is a good approximation of what happens when deaf Mary hears sounds. In the same time, this premise 2’’ is supposed to be consistent with the first premise that she already has all the possible physical information, and therefore the new acquired stuff is neither a skill nor physical information. But this is not non-physical information either, and in order to accommodate this claim it seems than we shall be convinced that a finer grain way of computing sound-related scientific data is equivalent with hearing. Because this computational information is not phenomenal, deaf Mary can know others’ computational information related with hearing. What stops her from discovering that she can use the computational information used by the others in order to operate the same finer grain discriminations for herself (since she posses all the physical and computational information available to the others)? Since she knows all the physical and computational information that is available to others -which can hear- I think that she may be able to make the same fine gain discriminations between the already possessed physical data for herself. If this is so, and since the finer grain way of discriminating is not phenomenal, I cannot see any reason why not she could not use the computational information that she is aware others use. Then deaf Mary should be able to know what is it like to hear before she hears. It is, firstly, counter-intuitive. Secondly, if she would know what is it like to have hearing-related K-qualia before she hears, she would find out nothing new upon unplugging her ears. Which contradicts premise 2’’.

The third challenge to the premise 2 is to maintain that it is void; that is, both knowledge argument’s premises can be made true under the physicalist interpretation, which means that the second premise says nothing more besides what was already said in the first premise. There are three versions of this claim: that what deaf Mary lacks is physical information, or that what deaf Mary lacks is, in fact, a certain mode of representing the already had knowledge, or, stronger, that deaf Mary lacks nothing.

Churchland buttresses all this versions due to his understanding of what K-qualia and knowledge means. For him, ‘the brain's basic mode of occurrent representation is the activation vector across a proprietary population of neurons - retinal neurons, auditory neurons, and so forth.’[28] Both knowledge and sensations are nothing more than complicated neural connections. The first conclusion is that sentential rationality and knowledge is only a peripheral activity of the neural connections, while the large mass of information is neuronal.[29] The second conclusion is that K-qualia is some minute combination between matrices of neuronal populations[30] and other tiny physical interactions, like ‘the spiking frequency of the signal in some neural pathway, the voltage across a polarized membrane, the temporary deficit of some neurochemical, or the binary configuration of a set of direct-current impulses’.[31]

Regarding the first version of his challenge to premise 2, Churchland claims that, given his account of how the neuronal system works, if deaf Mary finds out something new when she hears the sound of a drum, then this simply means that a certain ‘representational space within the relevant area of neurons’ was previously not configured.[32] As this new activation is describable in physical terms (like minute neuro-chemical details), it means that the second premise of the knowledge argument is either false (e.g., there is nothing phenomenal to be found out) or contradictory with the first premise (e.g. her initial physical knowledge was not complete since she still may acquire physical knowledge).[33]

The second version of his claim against 2 is that, if the first premise is true and if Churchland’s neuronal description of information and sensation is correct, then what deaf Mary lack is neither phenomenal nor physical:

‘The difference between a person who knows all about the [hearing] cortex but has never enjoyed a sensation of [drum sound], and a person who knows no neuroscience but knows well the sensation of [drum sound], may reside not in what is respectively known by each (brain states by the former, qualia by the latter), but rather in the different type of knowledge each has of exactly the same thing.’[34]

This can be so because both the scientific information that deaf Mary has before hearing and her drum sound’s qualia after unplugging her ears are represented in a neural form within her brain. The only difference is that, in the case of deafness, the relevant neural connections between the neural population representing the information within her brain are made by using a certain neural path which does not include the auditory nerves. In the case of experiencing sounds, the connections between the same neural populations representing the same information within her brain are made using additional or different auditory neural paths. If so, he concludes that the second premise is simply false.

The third version of the claim that premise 2 is void is offered by taking seriously premise 1, namely that deaf Mary possesses all the possible hearing-related facts of the sort in principle expressible in the vocabulary of physical science. Given the premise 1 and the accuracy of Churchland’’s neurocomputational account of information and qualia, one can claim that deaf Mary, after unplugging her ears, will find out nothing over and above already possessed knowledge. It follows consequentially that the information available to deaf Mary might allow her to approximate very close the cortical state (or neural path) produced by a sound, to the point that the perceivable difference between this approximation and the sound-produced stuff is almost imperceptible.[35] Since qualia are concerned only with conscious introspective discriminations, for a qualia-supporter the aforementioned difference shall not count: experience teaches deaf Mary nothing new from an introspective point of view. Which means that physicalism leaves nothing out and premise 2 is void; to regard it otherwise would beg the question in favor of phenomenal knowledge. 

From Churchland’s challenges to premise 2, I will focus only on the last two versions. This is so because the first version proposes a physicalist re-interpretation of the premise 2, on assumption that premise 1 is false. It means that the first version misses the anti-physicalist point by ignoring the refined version 1’.

The second version, which proposes re-interpreting phenomenal knowledge as a new mode of accessing or representing physical knowledge, is not a relevant objection against premise 2. If phenomenal knowledge were a bare new mode of accessing physical knowledge, then it would be equal to state that phenomenal knowledge is just a translation of physical knowledge into another language. If so, then phenomenal knowledge would be a kind of knowledge that can be contained within physical knowledge. The reason is that a new language, in and of itself, does not bring any new knowledge (except its new words). The fact that a new language differs from the old one by the use of synonymous terms (e.g., just as English can be mapped into Romanian), or by the use of a different kind of language (e.g., just as sentential information can be mapped into neuronal information), is not new knowledge about what it is reported (e.g. what it is like to hear) by that language. Thus, to interpret premise 2 as reading that what deaf Mary lacks is a new language for her old knowledge, is to misunderstand that what phenomenal knowledge claims to be is a substantial knew knowledge about K-qualia.[36]

Further, Robinson confutes the third version of Churchland’s challenge to the premise 2 by insisting that the proposed neuronal conception of qualia is not relevant for the knowledge argument, even if it were correct from the physiological or functional perspective. If qualia would be neurophysiologically represented as some minute combinations between neural paths and other tiny electro-chemical interactions, this would make no difference for deaf Mary, since those physical realizations are not experientially discernable as such. Nonetheless, qualia are meant to point towards her subjective what it is like to hear drums and not towards what is it happening below the level of hearing drums.[37] At this point, Churchland’s reply is that this is not an objection against his point, since what one can introspectively discriminate depends more upon the acuity of the available vocabulary than upon the profoundness of the level where one discriminates qualia. All that the objection shows is that Mary does not have the appropriate vocabulary in order to discriminate exactly at the level of neuronal pathways. If she would be able to introspectively locate her qualia at the same minute level with the level of neurophysiological description, then there would be no mysterious gap to be filled with respect to qualia. If she would use a language that offers her a large enough array of expressing all her minute discernable experiences, then she would produce sophisticated reports, accurately approximating his proposed neuro-physiological process for qualia. It is not a problem of her introspective discriminatory limit, but one of a language sharp enough to catch all the details of her introspection.[38] Take, for example, a child who cannot discriminate all the instruments when she listens to Beethoven, not because she cannot do it in principle, but since she does not have an appropriately fine language to deliver sophisticated reports. Give her the appropriate theoretical musical training and she will be able to discern various individual sounds and instruments which she had not been able to introspectively discern before. Churchland claims that, if this can happen in the case of music, then there is no reason to doubt that the same can occur with neuro-physiological processes. All one needs is appropriately sharp vocabulary and it is possible that this vocabulary will take the place of the actual mentalistic terminology. Notwithstanding, Robinson does not consider that a sharper language can make any difference for what it is like for deaf Mary to hear the drums. This follows since the accuracy of sensory and introspective mechanisms giving her the specific K-qualia are constant, irrespective of the language used to report them. Suppose that Churchland would succeed in educating a child to use a very sophisticated musical vocabulary; at maturity, she will be eventually able to discriminate introspectively at a closer neurophysiological level than anyone sound-related qualia. We can even accept that she will discern more sounds and instruments (i.e., she will have more sound-related qualia) than we do. However, what she feels like when she hears a sound is not changed, regardless of the introspective deepness of those sound-related qualia. For instance, take the extreme case that she will be able to discriminate what happens physiologically at the very end of her neuronal pathways. Then, according to Churchland’s theory, what she encounters will not be expressible any more in physical terms, simply because at the very end of neuronal pathways there are no more pathways to talk about. Something that can not be known through physical concepts will escape neurophysiological description. I, the one not discriminating the particular sound hearable only for her, can still know what kind of experience she encounters. I can do so precisely because I have experienced sounds as well, that is, I know what it is like to have sound-related qualia. To compare, deaf Mary cannot know what it is like for this musical genius to experience any sound, regardless of its introspective closeness to neurophysiological processes. Deaf Mary might have received the same in-depth musical training as Churchland’s student: she is not able to know the sound-related qualia because she does not have the relevant experience, not due to the fact that she lacks a sharp vocabulary. All in all, a very minute report of K-qualia’ neurophysiology cannot yet feel like K-qualia. Therefore, this challenge to the premise 2 of the knowledge argument does not get the point either.

I am turning now to a counter-argument that accepted that, up to this point, the knowledge argument is neither pointless nor reducible to something else. Nevertheless, even if there might be a sound and clear version of the knowledge argument, it would leave physicalism unaffected. The strategy to show that physicalism should not be bothered by the existence of the knowledge argument is by trying to demonstrate that, if the knowledge argument would be sound and true, then it would turn against its proponents as well. Since the knowledge argument seems to also demonstrate the contrary of what was intended to, then one can conclude that the strategy employed by it leads to puzzling outcomes and can not be considered as a proper objection to physicalism. 

Churchland intends to reject the knowledge argument on the aforementioned ground. His idea states that:

 ‘If it works at all, [the knowledge argument] works against physicalism not because of some defect that is unique to physicalism; it works because no amount of discursive knowledge, on any topic, will constitute the nondiscursive form of knowledge that Mary lacks. […] Even if substance dualism were true […] an exactly parallel ‘knowledge argument’ would ‘show’ that there are aspects of consciousness that must forever escape the story.’[39]

To this, Jackson rejoins that a property dualism is not affected by a parallel knowledge argument. This is so simply because premise 1, which would have to say that deaf Mary posseses all the possible knowledge about property dualism, cannot be made from the property dualism perspective.[40]  Notwithstanding, Churchland can rebut by stressing that he talks about substance dualism rather than property dualism. Robinson gives a more appropriate answer to Churchland, by pointing out that a parallel knowledge argument might not formulate its premise 1 in the required manner since substance dualism does not offer a knowledge about qualia that is entirely expressible in the third person’s terminology.[41] In light of this clarification, it seems that Churchland misses his blow once more. Precisely, the parallel knowledge argument suggested by Churchland was the following:

 

1.      Deaf Mary (before taking off the earplugs) knows everything that can in principle be expressed in the vocabulary of substance dualism science about hearing.

2.      Deaf Mary (before taking off the earplugs) does not know the phenomenal nature of the sound.

ð 3. The phenomenal nature of sound in principle cannot be characterized using the vocabulary of substance dualism science.

 

By his reply, Robinson denies premise 1 and the argument is:

 

1’. Deaf Mary (before taking off the earplugs) cannot have scientific knowledge in substance dualism’s terms about hearing.

1.      Deaf Mary (before taking off the earplugs) does not know the phenomenal nature of the sound.

ð 3. The phenomenal nature of sound in principle cannot be characterized using the vocabulary of substance dualism science.

 

If it were the case, the parallel knowledge argument’s premises are not sufficient to secure the conclusion. Moreover, even if the conclusion would be shown to be true by a different rationale, it would not touch dualism, since the dualist never claimed that there were such a scientific knowledge like the one mentioned in 3.

Nevertheless, one can say that Robinson’s answer is not satisfactory enough. The denial of a purely scientific perspective provided by substantive dualism gives the impression that the question is begged in favor of dualism: 1’, 2, and 3 looks like versions of the same idea. Churchland claimed that if substance dualism maintains that the mental consists of something, like the ectoplasm, then a scientific insight on that should be possible. And, if there is some scientific knowledge about the ectoplasm, 1’&2&3 invalidates the anti-physicalist position as well. However, if Robinson had ignored Churchland`s point, then he would have unwarrantedly maintained that, even if there were an ‘inner substance’ or ‘real essence’, there couldn’t be any knowledge expressible in the third person’s terms about it. Robinson’s reformulated argument is yet not simply ignoring the underlying insight of Churchland’s argument. He rather maintains that an anti-physicalist proponent does not need to be a substantial dualist. He denies 1 and maintains 1’, on the ground that there is no mental ‘substance’ to be known. The anti-physicalist proponent needs not be a (substance) dualist in order to construct the knowledge argument.

As we can see, there is a certain interpretation of the knowledge argument that appears valid and withstands counter-arguments or softening interpretations. Before proceeding to the next section, I shall sum up the ways to misunderstand the point of the knowledge argument. Precisely, the knowledge argument does not point to a lack of either:

-         physical knowledge;

-         knowledge about a mental substance or essence;

-         new concepts (about physical knowledge);

-         finer concepts (about physical knowledge);

-         more subtle discrimination with existing physical knowledge;

-         new mode of representing physical knowledge;

-         ability (know-how);

-         imagining high-degree resemblance of K-qualia;

-         K-qualia related experiences or reactions;

-         egocentric (de se) knowledge;

-         ersatz knowledge.[42]

All theses assuming anyone of the aforementioned options as the meaning of the knowledge argument shall be rejected as begging the question against it (or as ignoring it).

 

The clean version of the knowledge argument

 

            The conclusion of the previous section is that there is a sound anti-physicalist version of the knowledge argument. The aim of this section is to demonstrate that there is only one interpretation that conserves the soundness of the knowledge argument.  Namely, the knowledge argument constructed around a deaf person is the only sound version of the argument, while the knowledge argument constructed around a color-blind person is not. I claim that the difference between a deaf Mary and a color-blind Mary is crucial, being more than a simple detail of exemplifying the point of the knowledge argument. Consequently, I think that the proponent of Jackson’s interpretation of the knowledge argument cannot successfully make a case against physicalism. Correlatively, those which reject the idea that color-blind scientist Mary would learn nothing new when she is released from her room might be right. My position is that only a proponent of Robinson’s interpretation of the knowledge argument can succeed in making a case against physicalism.

            The rationale is the following. The anti-physicalists (in their majority) claim that the knowledge argument makes its point regardless of whether the example used is of a deaf or a color-blind Mary. The majority of the anti-physicalists is using these two examples as equivalent or interchangeable. The underlying assumption is that there is no loss for the knowledge argument if a phenomenal experience is replaced with another within the argument. All that counts for the success of the knowledge argument is that the example involved is of a phenomenal kind and not else. This last point was underlined in the end of the previous section.

            If the knowledge argument suffers no loss if we change one example of phenomenal experience with another, then one can construct the argument in various cases. Let us take some instances that are considered equivalent in the relevant way; namely, all of them are examples of phenomenal experiences.

 

Seeing colors

1. Color blind Mary knows everything which can in principle be expressed in the third party’s vocabulary of physical science about colors.

2. Color blind Mary does not know the phenomenal nature of colors before actually seeing colors.

ð 3. The phenomenal nature of colors in principle cannot be characterized using the vocabulary of physical science.

 

Hearing sounds

1’. Deaf Mary knows everything which can in principle be expressed in the third party’s vocabulary of physical science about sounds. 

2’. Deaf Mary does not know the phenomenal nature of sounds before actually hearing sounds.

ð 3’. The phenomenal nature of sound in principle cannot be characterized using the vocabulary of physical science.

           

            The claim is that these two arguments, 1&2ð3 and 1’&2’ð3’, are formally identical, and that both are variations on the anti-physicalist knowledge argument. Nevertheless, let us examine the ‘seeing colors’ argument closer. Premise 2 maintains that a person that has lived for her entire life in a black and white world does not know what it is like to see a color, say red. Precisely, the difference between Mary-in-her-black-and-white-room and Mary-in-colorful-world is that Mary-in-colorful-world has the experience of seeing, say, red. This difference is expressible as:

            A. ‘Mary knows what it is like to see black and white.’

            B. ‘Mary knows what it is like to see black, white, and red.’

            The difference between these two Mary’s mental states consists in what it is seen. Since black, white, and red are objects of sight, then the difference between Mary’s mental states is a difference between the objects of sight. The sight itself –the exercise of the sense - remains constant. The phenomenal difference is constituted by the difference between the objects of sight only.

            Now let us examine the ‘hearing sounds’ argument closer. Premise 2’ maintains that a person that has lived for her entire life with earplugs does not know what it is like to hear a sound, say a drum. Precisely, the difference between Mary-with-earplugs and Mary-without-earplugs is that Mary-without-earplugs has the experience of, say, a drum. This difference is expressible as:

            C. ‘Mary does not know what it is like to hear a drum.’

            D. ‘Mary knows what it is like to hear a drum.’

            The difference between these two Mary’s mental states consists in exercising her sense of hearing. The difference between Mary’s mental states is not a difference between the objects of hearing. The phenomenal difference is constituted by the difference between exercising and not exercising the sense, and not by the difference between the objects of hearing.

One can reject this expression of the difference between Mary-without-earplugs and Mary-without-earplugs, and maintain that the difference is expressible:

E. ‘Mary knows what it is like to hear nothing.’

F. ‘Mary knows what it is like to hear a bass-drum.’

In this case, the difference between these two Mary’s mental states consists in what it is heard. As the hearing itself – the exercise of the sense – remains constant, the phenomenal difference is constituted by the difference between the objects of hearing only. If this is the case, then there shall be a phenomenal difference between Mary-in-a-world-with-bass-drums-only and Mary-in-a-world-with-many-kinds-of-drums. This difference shall be expressible as:

G. ‘Mary knows what it is like to hear bass-drums.’

H. ‘Mary knows what it is like to hear bass-drums and shrill-drums.’

The difference between these two Mary’s mental states shall consist in what it is heard. Since bass-drums and shrill-drums are objects of hearing, then the difference between Mary’s mental states is a difference between the objects of hearing. The hearing itself – the exercise of the sense – remains constant. The phenomenal difference is constituted by the difference between the objects of hearing only.

If the rationale E-H is correct, there shall be no difference between the pairs A&B, E&F, and G&H. Precisely, if between A and B there is a phenomenal difference, there should be a phenomenal difference between E and F, and between G and H as well. The knowledge argument claims that if there is a phenomenal difference between two (mental) states, the difference it is bridgeable by personal experience only. In our example, the knowledge argument maintains that when Mary shifts from

A.     ‘Mary knows what it is like to see black and white.’

to

B.     ‘Mary knows what it is like to see black, white, and red.’,

she learns something completely new, which she couldn’t have learned otherwise. As we agreed that if there is a phenomenal difference between A and B, there shall be a phenomenal difference between G and H as well, then the knowledge argument shall maintain that when Mary shifts from

G. ‘Mary knows what it is like to hear bass-drums.’

to

H. ‘Mary knows what it is like to hear bass-drums and shrill-drums.’,

she learns something completely new, which she couldn’t have learned otherwise.

            However, this conclusion is unacceptable, because when Mary heard the first sound, which in our example was a bass drum, she learned what it is like to hear. Therefore, the difference between G and H there is not a phenomenal difference like the one between E and F. Our rationale does not yet show any difference between the pairs E&F and G&H. As G&H was constructed as formally equivalent with E&F, it means that if the result is puzzling, the fault lies in the way E&F was constructed. My position is that E is not a correct formulation, namely, it cannot be said that deaf Mary’s state is expressible as ‘Mary knows what it is like to hear nothing.’ If E is not a correct expression, then C remains to express Mary’s deafness: ‘Mary does not know what it is like to hear a drum.’. Furthermore, E&F was constructed as formally equivalent with A&B. Since E is not a correct expression of Mary’s deafness state, it might be the case that A is not a correct expression of Mary’s color blindness either.

            Nonetheless, the pair A&B is not equivalent with pair C&D. In the case of A&B, the phenomenal difference is constituted by the difference between the objects of the sense and not by that of exercising or not the sense. In the case of C&D, the phenomenal difference is constituted by the difference between exercising or not the sense, and not by that between the objects of the sense. Since pair A&B expresses premise 2, and pair C&D expresses premise 2’, and pair A&B is not equivalent with pair C&D, I conclude that premise 2 is not equivalent with premise 2’. Concretely, I claim that 1&2ð3 is not equivalent with 1’&2’ð3. The ‘seeing colors’ argument is not equivalent with the ‘hearing drums’ argument and the difference between them is substantial for the anti-physicalist strategy. As already stressed, the argument that is constructed around color blind Mary reaches contradictory outcomes and turns against its proponents as well. To compare, the argument that is constructed around a deaf Mary is non-contradictory and directed against physicalism only.

 

Conclusion       

 

The difference between deaf Mary and color-blind­ Mary is not a difference between the sense of hearing and one of seeing. I do not claim that the knowledge argument makes a case against physicalism if it refers to sounds, but makes no case if it refers to colors. The difference between deaf Mary and color-blind Mary is between a case where a sense is completely absent and one where a sense is partially absent. It is like the difference between a completely blind Mary and a color-blind Mary. My claim is that the knowledge argument makes a case against physicalism if it refers to a complete absence of a type of sensory experience, but makes no case if it refers to a partial absence of a type of sensory experience. In this respect, deaf Mary makes a good case against physicalism, whereas color blind Mary does not.

If so, the dispute between physicalism/anti-physicalism concerned with answering the question ‘Does Mary learn something new when she experiences red for the first time?’, or any other version of it (e.g. ‘Does I learn something new when I experience for the first time the taste of Vegemite?’[43], and so on) is totally misplaced. My rationale implies the following. On the one hand, the anti-physicalist that answers ‘Yes, Mary does learn something new when she firstly experiences red.’ cannot claim that this is a case against physicalism. On the other hand, the physicalist that (credibly) answers ‘No, Mary does not learn something new when she firstly experiences red.’ cannot claim that the anti-physicalist was refuted.

In conclusion, if my point is right then most of the produced argument pro or con physicalism should be revisited. For the time being, these arguments are fighting against Quixotean windmills, marking points for or against a dubious color-related – which is a partially exercise of a sense - problem.

 

 

 

 

Cristian Vasilescu

2002

 

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