Synesthesia is, roughly speaking, the mixture of information coming from different senses. It is the mental phenomenon or state that is (sincerely and literally) expressed by utterances such as I see this voice as green, I don't remember her name, but it was a green name or I feel pain in triangular shapes. It leads to temporary illusions and has to be distinguished from the literary or metaphorically mixture of sense-related words, such as words for sounds and words for colors. As such, synesthesia raised psychological interest, regarding its explanation, neurological counterpart, influence on personality etc. The aim of the present paper is to sketch some of the philosophical problems related to synesthesia.
The empirical basis of this essay is Cytowic`s book, Synesthesia. A Union of the Senses. I rely heavily on the factual information provided in this book for my remarks.
Typical synesthetic utterances are of the form: when I am working at my computer, I am oblivious to everything, and so am not really aware of the colors the clicking of my keyboards makes as I type`` , if i am listening to a song and then play it back on a recorder, the visual patterns will vary because they`re not exactly alike. I usually see shapes of some complexity that is everchanging as does the sound that stimulates it ``. Occasionally, synesthetes have the tendency to ``adjust`` the real colors of some visual objects because they are not ``fit``: for example, if a synesthetes has the constant association of the written numbers in the 20 series with the color red, s/he will object to a blue drawing of one of these numbers.
Ocassionally, a synesthetes will feel some colors as wrong, in that they do not fit his/her color-sound or color-letter associations. That is, each printed (type-)letter has an essential or intrinsic color, even if it is contingently printed in a different, ``wrong`` color. Sometimes, synesthetes use their associations to recall past events:
Synesthesia is a rare phenomenon (about one person in 300000) characterized by involuntariness, durability of associations, projection into the physical reality and emotional accompaniment. That is, it is unsupressable and cannot be conjured up at will; synesthetes do not choose their associations. These associations, such as of e with yellow, are constant throughout a synesthetes` life. Synesthetic percepts do not come up analyzed into more basic components such as sense data, neither are they felt as constituting more elaborate percepts : the association of the object of perception generated by synesthesia with the real images is spontaneous and it is not felt as a combination of two different objects, one ``real`` and the other ``mental``. Synesthetes investigated by Cytowic insist that their perceptions are ``real`` and their way of speaking is the best to express their experiences. Visual synesthetic experiences are projected into the real space and do not come to the conscience as mental representations . As it were, synesthetic experience are hallucinations, but they are ``real`` hallucinations: understanding that they present a deformed picture of the reality (``colors are not really there``) is provided not by the perception itself, but by the beliefs and education: Cytowic`s book contains accounts of children who avowed synesthetic experiences and were considered crazy by their parents, teachers etc. It is likely that the belief that numbers, smells and shapes are not really ``colored`` is only the result of education and communicating with ordinary, non-synesthetic people.
It seems obvious that synesthesia is the source of some puzzles. First, synesthesia is puzzling for the current intuition that there is a set of qualities corresponding to each sense, and that mixture of them is unconceivable. Synesthesia seems to transgress the boundaries of the conceivable (or, if we were to follow a fashionable distinction, to illustrate the conceivable impossible) . Secondly, were we to admit the literal possibility of a mixture of the senses, synesthesia poses an explanatory puzzle for an evolutionary way of psychological explnation: indeed, the sense of biological evolution was towards more and more specialized functions of the sense organs. Synesthesia is thus vestigial and evolutionary earlier than the separation of the sense-qualities fit to our semantic categories. Third, synesthesia poses a challenge to any theory of the mind that rigidly separates between cognitive compartments at the ``inferior``, i.e. sensory level of mind's architecture.
And, as we shall see below, synesthesia is also a challenge to Wittgenstein's private language argument. As a matter of fact, my interest in the problem of synesthesia was a particular memory- association that I made when stumbling upon Cytowic`s book about ``the union of the senses``. It made me think about a passage in Wittgenstein's Philosophical Investigations that I have never been able to grasp, namely:
The secondary sense is not a `metaphorical` sense. If I say ``For me the vowel e is yellow, I do not mean `yellow` in a metaphorical sense, - - for I could not express what I want to say in any other way than by means of the idea `yellow` ``
Cytowic`s book contains references to writers who have expressed their synesthetic associations, some of them being supposedly genuine synesthetes, such as Arthur Rimbaud and Vladimir Nabokov. However, the occurrence of the name of Wittgenstein on such a list should raise, if not for a professional psychologist then at least for a philosopher, some deep questions that cannot be simply answered with ``Maybe Wittgenstein too was a synesthetes``.
2. Synesthesia and the private language argument
There are several different ways in which Wittgenstein's famous private language argument (PLA) can be exposed. My interest in the following lines is not to present in details this aspect of Wittgenstein's later philosophy, but to draw its consequences for the issue of synesthesia. First, the many different ways in which PLA can be presented are related to a clarification of the meaning of ``private`` involved here. There is an ontological privacy (that characterizes or is supposed to characterize entities possessed, owned only by one person: this kind of privacy is involved in clich�s such as ``only I can have my pain`` see PI 253); epistemological privacy (the property of an entity to be such as it is accessible to the knowledge as/or acquaintance of only one person : ``only I can know I am in pain, other people can only believe it`` ); thirdly, there is semantic privacy: the property not of a "mental entity`` but of a word, of being such as it is intelligible only to one person. Clarifying the logical relationship between these sense of privacy(i.e., answering to questions such as ``can something be ontologically private and correctly designated by a word that is semantically non-private ? or: can something be epistemically but not ontologically private ? or especially: should we introduce modal qualifications, such as necessary privacy ? )are beyond the scope of this paper
Wittgenstein's critique seems directed against all of these three kinds of privacy. Some exegetic details may show that actually he maintained ontological privacy of ``entities`` such as pain, and it is precisely in virtue of this ontological privacy that he rejected the semantical and epistemological privacy.
A further point that needs to be noticed is that the general framework in which PLA occurs is the rejection of semantic realism (the theory or assumption according to which all words function on the model of names, viz. their meaning is the real entity designated by them). Indeed, one possible reconstruction of the PLA is: if psychological entities were hidden in a receptacle owned only by and accessible only to their possessor, it would be impossible for any other person to intelligibly refer to his/her mental states. But, as our daily experience shows, meaningful talk about each other’s ``psychological entities`` is possible. It follows that either it is false that these entities are hidden in a receptacle accessible only to their possessor, or/and talk about ``inner states`` can be done from a non-realist standpoint, i.e. without the assumption of the ‘beetle in the box ``: one can talk about something even in the absence of the logical possibility of ``pointing to it``. The rejection of the realist picture of meaning is related, inter alia , with PLA in the sense that it dispenses from the problems aroused by a language referring to entities ontologically private. By a rough approximation, we can say that rejection of the realist picture about meaning is a presupposition which PLA helps to clarify.
A consequence of PLA concerns the learning context of psychological words. One does not learn to use these words from one’s own case , in order to apply them (by analogy) to other person’s case. Of course, PLA does not have any ``behaviorist`` consequence, in the sense that no one has a privileged stance towards one’s own mental states. On the contrary, Wittgenstein maintained first-person authority (FPA), in the sense of the impossibility of disputing one’s words when they speak about their mental states. The meaning of ``It is meaningless to say that only I can know I am in pain`` is not to suggest that I am ignorant about my own case, but rather that it is pointless to speak of knowing where there is no possibility of rational doubt. The reasoning from FPA to the possibility, or necessity of a private language is illegitimate; people are taught psychological words in a way that does not entail private ostensive definitions.
This sketchy presentation of PLA was meant to show that a private naming, understanding and/or grasping of one’s mental states is not entailed by FPA; more specifically, it is incompatible with FPA and semantical realism. Since at least FPA has a basis in the ordinary language, it seems that we should abandon the semantic realism.
3. The Synesthetic Challenge to PLA
What is the connexion between PLA and the problem of synesthesia? Well, it appears that Wittgenstein, in his remarks about psychological terms and the correctness (or lack thereof) of using them, was mainly concerned with usual, ordinary examples like ``pain``, ``thought``, `` hope`` and the like. But synesthetic ways of speaking, and/or synesthetic experiences are not like ``ordinary `` sensations like toothaches. The main difference here is that it is implausible that synesthetic ways of avowing one’s experiences should have been learned in the way that words like ``pain`` or ``toothache`` were learned. The reason is that synesthetic parlance is NOT a part of the ``normal`` language-game used by the community; it is not positively sanctioned by the ``form of life``. Of course, it does not seem implausible that people start to utter sentences never heard before, in order to avow their experiences; it would be no wonder if a child who never heard anyone speaking about pain in the left side of the brain should complain about such a sensation. On the other hand, it would seem highly implausible that a person should start to complain about headaches if s/he has never heard the word ``headache``: there is no internal connexion, we would like to say, between the word ``headache`` and the experiences accompanied by it.
And the main question then arises: how is it
possible for one to avow his/her experiences in a synesthetic way,
although s/he has never been taught (at least explicitly taught) to
express them in such a way, and, moreover, to do so hen the linguistic
community rejects such a way of speaking that attributes colours to
sounds? Can Wittgenstein’s PLA do justice to the problem of the
``generation`` of synesthesia? This question has two components:
(a) why does a synesthetes describe his/her experiences in
synesthetic parlance, in words like `` I can see this voice``, instead
of choosing a more ordinary description of one’s experience? (Say:
synesthetes speak in metaphors; their actual experiences are reducible
to more common ways of speaking);
(b) why does a synesthetes still use words that belong to
our ordinary vocabulary ? (``voice``,`` red``,`` seeing``), in order to
avow his/her mental states, instead of forging a new word
(Wittgenstein's sensation "S";) for them, complaining that the ordinary
language lacks the resources necessary for such a purpose (``my mental
states are ineffable``, as it were) and that he has no other option
than expressing him/herself in (good or poor) poetry ?
From a linguistic point of view, synesthesia is at mid- distance between common way of playing the psychological language-game and the arbitrary introduction of a new symbolism that couldn’t be checked for its intersubjective validity (``I have the sensation S``) . If we keep on with the analogy between language and chess, we should say that the synesthetes, or at least the person who speaks like a synesthetes, is like someone who moves both the horses and the rooks in the same way, as a horse and as a rook (jumping in L like a horse and moving along horizontal-vertical paths like rooks).
Not only that there is a synesthetic way of speaking, but there are also standards of correctness concerning it. The synesthetic way of speaking has not been learnt and, it is argued in psychological empirical research, it is manifested constantly by children who haven't the least intention of expressing themselves metaphorically or of deceiving the others with respect to their mental states. It seems we have no option left but to admit that a synesthetes speaks following his/her own rules. If this raw conclusion is true, it follows that the very possibility of synesthesia disconfirms Wittgenstein's PLA and the methodological collectivism that subtends it. Indeed, the synesthetes seems to follow rules that he has privately established , and that coincide with the rules privately established by other synesthetes whose existence is unknown to him. This patently gainsays the thesis that no one can follow a rule privately. More precisely, the question is: what is the source of the standards of correctness of the synesthetic way of speaking ? And: Is the very existence of such standards of correctness a reason for rejecting Wittgenstein`s PLA ?
If so, then it should be surprising, all the more so since we know Wittgenstein did know about a phenomenonא at least similar to synesthesia, as he wrote in the paragraph where the vowel e had been felt as yellow.
4. The anti-nativist bias in Wittgenstein`s PLA
As I think it is obvious, PLA is an illustration of what may be called ``methodological collectivism``, of a stance towards language that favours effective learning and neglects/denies a rationalist, ``innate ideas`` approach to the generation of language. Contrary to a widespread misunderstanding, Wittgenstein did not reject the importance of ostensive definitions in learning the meaning of the words; it is true, of course, that an ostensive definition can be misunderstood or misinterpreted, but Wittgenstein accounts for the success or failure of an ostensive definition in termsof the general framework or form of life in which the ostensive teaching takes place.(A Chomskyan, nativist would have perhaps looked for a faculty of the mind that provides for the correct understanding of ostensive definitions; say, in the case of the example of the ostensive definition of a pencil that Wittgenstein offers at the beginning of the Blue Book, a nativist would have looked for a mental capacity that knew to select from all possible ways of understanding the word ``pencil`` that sorted as a `name of a class of artifacts``, eliminating the hypotheses of ``name of a color``, ``name of a number``,``name of a form``,`` proper name`` etc.). Briefly , the contrast between a wittgensteinian approach and a nativist one could be expressed as the contrast between methodological collectivism and methodological individualism respectively.
Of course, I do not claim that the opposition between a wittgensteinian and the Chomskyan approach to language is reducible to that between two methodological attitudes. One must not forget that Wittgenstein`s interest was primarily a philosophical one, albeit in his conception of philosophy as a way of dissolving problems and putting before everyone`s eyes what lies open to view. Wittgenstein`s concern was not with framing empirical hypotheses, but with clarifying conceptual mistakes . On the contrary, Chomsky and the nativist trend in psychology deals explicitly with empirical hypotheses: such are the hypotheses that there is a faculty of language, that literally grows, and that language cannot be properly taught, but only learnt (in the sense of involuntary growing).
Synesthesia does represent, in my opinion, an argument for a Chomskyan, nativist, methodologically individualist theory of the mind and language, and against the Wittgensteinian methodological collectivism exposed in PLA. Of course, I do not mean that Wittgenstein could not have accounted for the problem of linguistic creativity and that the mere remark that people can understand sentences they have never heard before would have been for him a novelty, a thing he simply didn’t think about and that would have ruined at one stroke the spirit of his philosophy. But still he uses the empiricist premise that the contribution of the linguistic community is the decisive ``cause`` of understanding an expression. In the case of synesthetic ways ofspeaking, such an explanation simply doesn’t work; if we believe Cytowic`s book, synesthetes acquired a form of avowing their experiences in a way that hasn’t been positively sanctioned by the linguistic community and that, moreover, infringes upon its standards of correctness. Moreover, synesthesia favours obviously one of the central tenets of Chomsky`s doctrine, namely that language is not a explainable teleologically (its purpose is not communication).
In order to see the empiricist (learning, and not growing) account of understanding the meaning of words that Wittgenstein provides, one may simply re-read his account of an unusual experience ,namely that of ``feeling water beneath the earth``, in the Blue Book. After taking into consideration the case of the man who detects the presence of water by a , we would say, para-normal ability and certain peculiar feelings in the hand, Wittgenstein writes:
Supposing the diviner said ``I have never learnt to correlate depth of water under the ground with feelings in my hand, but when I have a certain feeling of tension in my hands, the words `three feet` spring up to my mind. . . . Yes, but you see that the meaning of the words ``I feel the depth of the water to be n feet`` has to be explained; it was not known when the meaning of the words n feet in the ordinary sense (i.e.,in ordinary contexts) was known.. We said before that we should not have been puzzled about the diviner`s answer if he had told us that he had learnt how to estimate depth. Now learning to estimate may, broadly speaking, be seen in two different relations to the act of estimating: either as a cause of the phenomenon of estimating or as supplying us with a rule (a table, a chart or some thing) which we make use of when we estimate .
I think the experience of ``colored hearing`` can be broadly analyzed on the pattern of the experience of ``feeling water under the ground``. We would like to say: feeling water in one hands in such a sense involves a secondary sense of `feeling water``, the same way that hearing colours involves a secondary sense of ``color``. And it is precisely here that we can analyze the debt Wittgenstein paid to an empiricist account of learning: I think his point is that learning in the second sense distinguished above is the only sort of learning that can be related to norms, to standards of correctness. The first case of ``learning``, i.e. the causal model of estimating (and, by analogy, the causal model of avowing an experience: ``whenever I have this experience I utter the words `this voice is green` `` cannot count as a part of human language. If we follow Wittgenstein`s path, then we should say that synesthetic utterances cannot be part of a language game .
As a point of Wittgensteinian exegesis, it should be noted that the expression ``secondary sense`` occurs only twice in the text of Philosophical Investigations; in the passage just quoted from II xi and in par. 282, where ``pitying of inanimate things (e.g. dolls) for being in pain`` involves a secondary sense of the concept of pain. In par. 282, the ``secondary sense`` of a word is defined as that sense which is far from the paradigm-cases of applying it. In the light of the considerations related to ``the vowel e is yellow for me`` and the , I think, illuminating passage from the blue book with the diviner who feels in his hands water under the ground, I understand the ``secondary sense`` as the usage of a word that hasn’t (yet) been tested intersubjectively, that is only causally determined by a certain feeling of appropriateness, and not normatively determined by the rules of the language-game.
The phenomenon of synesthesia shows that the secondary usage of psychological words is nevertheless part of a potential language-game. Cytowic`s book provides details about cases in which several synesthetes met and understood each other`s way of speaking without any explicit training. (One should perhaps say that synesthetic parlance is dead metaphor, but we should be cautious about the person(s) to whom it seems as a dead metaphor, or as a normal way of speaking). And this possibility rules out as highly implausible any explanation in terms of methodological collectivism. (in order to maintain the methodological collectivism, one should perhaps say that the rules of using the color- and sound-words in the ordinary language are flexible to the point that they allow avowals of synesthetic experiences; such an assumption is but an epycycle, unnecessary all the more so since there seem to be explicit rules about sound-color associations, for example, rules that openly contradict the common sense intuition that a sound can have no color, that we can hear but not see voices and that information coming from different senses is itself ``encapsulated``). The most intuitive explanation of synesthesia (and of synesthetic speaking) is that of a particular kind of experiences, that trigger causally in a relatively uniform way a particular kind of avowals.
Does it follow that, since the methodologically individualist type of explanation is the best to accommodate for synesthesia, PLA should be entirely rejected ? Not necessarily. To the extent at which Wittgenstein meant by PLA a normative characterization of the way in which psychological words have to be learned in order that a linguistic community be homogenous , i.e. everybody should understand everything that everyone else says, PLA remains valid (including the alleged impossibility of a private ostensive definition, the sensation `S` in par. 258), and all that has to be said is that the synesthetic language game cannot be accepted as part of the same language game as the ordinary-language one. But to the extent at which we recognize the meaningfulness of such a notion as potential language- game in which the primary sense of the words would be the secondary sense of words in our language, then Wittgenstein`s tacit assumption that one cannot obey a rule privately is wrong. Indeed, one can obey a rule privately, in the sense of the causal connexion between certain experiences and certain avowals of it.
The answer to the second question raised above, i.e. why synesthetes use still words from the ordinary language instead of forging a new word for the association of color and sound etc, is a little bit more intricate, since it involves the problem of measuring the distance between two language games. The only answer I can offer is a transcendental one: we, i.e. non-synesthetic people, who have never had the perception of a coloured voice, can understand synesthesia. The synesthetic way of speaking cannot be much too far from the ordinary language. And it is because we can understand such a phenomenon (understand: i.e., not dispute its psychological reality, the sincerity of people who express themselves in such a way; looking for a neurological explanation of synesthesia) provides for the relative resemblance between the ordinary language game and a language game that admits, if not that sounds have colours, at least the appropriateness of avowing certain experiences by attributing colors to sounds. As it were, the explanation of the fact that synetsthetic parlance is not very different from common parlance is simply the fact that we understand synesthesia; we should not inquire if we really understand synesthesia but to draw the consequences from the obvious fact that we do .
Bibliography :
Cytowic, Syhesthesia. A Union of the Senses
Wittgenstein, Philosophical Investigation
The Blue Book
Daniel Barbiero , A Note on Framing theInnateness
Hypothesis,at
http://csmaclab-
www.uchicago.edu/philosophyProject/chomsky/innateness2.html