All the interpretations discussed in the preceding section are plagued by the memory-challenge. None of them explains why the diarist cannot use his private names correctly in a short period, if his memory is reliable for that period.
It is also interesting to note that the expression ‘remembering the connection right’ is understood differently by different commentators. To memory-skeptics and Pears, this expression means identifying future sensations with the initial one. To the other commentators, it means remembering the meaning of ‘S’ (Kenny, Hacker, Stroud, McGinn), remembering the rule right (Candlish), or remembering the correlation between ‘S’ and a sensation (Canfield and Wrisley). What does the expression really mean by Wittgenstein? It seems that a crucial step towards a correct interpretation of Wittgenstein's remarks on private language is to get a precise understanding of the expression ‘remembering the connection right’. I shall therefore start with a discussion of what Wittgenstein means by that important expression.
3.1 Remembering the connection right
In PI 258, Wittgenstein writes: ‘But “I impress it on myself” can only mean: this process brings it about that I remember the connexion right in the future’. The text shows that the connection is between the sign ‘S’ and ‘a certain sensation’, which is introduced at the beginning of PI 258. Now, what does Wittgenstein mean by ‘remembering the connection right in the future’? In ‘Notes for Lectures on “Private Experience” and Sense Dada’ (LPE hereafter),51 he provides a number of remarks pertaining to this question. Let us start with Wittgenstein's remark about the diary in LPE:
But I could use language just for making entries in my diary and without ever having learned it. I could have invented a name for the particular colour sensation, say, the name “red” and then used this name to note down whenever I had that colour sensation. That means, you (would) play a private language game with yourself. But let's see, how are we to describe this game?—Christening. The words “‘seeing red’ means a part[icular] experience” are senseless unless we can follow them up by namely this → (pointing) or else they may say experiences as opposed to phy[sical] obj[ect], but then this is grammar.52
It is worth noting that Wittgenstein's diarist here invents a colour name ‘red’ and writes it in the diary. Here, ‘red’ is obviously meant to be a private name, not a public name. In PI 258, Wittgenstein uses ‘S’ instead of ‘red’, maybe because he thinks that ‘red’ is already a word in English (which is a public language) and that ‘S’ would be a better example of a word in a private language. So, the diarist in PI 258 writes ‘S’ when he feels a sensation of the type S, rather than ‘red’ when he has a certain colour sensation. Comparing the above remark in LPE with PI 258, and with appropriate substitutions, we get:
The words ‘“feeling S” means a particular experience’ are senseless unless we can follow them up by: namely this → (pointing).53
This means: if the diarist at t2 says that he is feeling S again, he should be able to point to s2 and say ‘this is S’. In other words, the diarist called s1 ‘S’, now he should be able to point to s2 and also call it ‘S’. What this means is: he should be able to correctly reidentify the sensation-type S. I shall call this reading the ‘reidentification-reading’.
Two subsequent remarks in LPE support this reading:
So he can be sure, in this private way, of what t[oothache] means by having a priv[ate] sens[ation]?54
Making sure that you know what ‘seeing red’ means, is good only if you can make use of this knowledge in a further case.55
Here, Wittgenstein uses both ‘toothache’ and ‘red’ to illustrate his point. The private diarist invents a name, e.g. ‘toothache’, ‘red’ or ‘S’, for his private sensation. The first of the above remarks questions whether the diarist can make sure what the name means through private ostension. The second of the above remarks states that for the diarist to claim that he knows the meaning of the private name, he must be able to use this knowledge in a further case, i.e. he must be able to determine whether or not a future sensation is a toothache, red or S.
The reidentifcation-reading is strengthened by a further remark in LPE:
“But when you ask me ‘do you know what t[oothache] is?’ I answer ‘yes’ after having brought before my mind a certain sensation”. But how is this certain sens[ory] character[rization] used?56
This remark means: to say that you know the meaning of ‘S’, you must be able to characterise a particular sensation, e.g. s2, as S.
A more explicit support for this reading comes from the following remark in LPE:
In our priv[ate] lang[uage] game we had, it seemed, given a name to an impression—in order, of course, to use the name for this impression in the future. The def[inition], that is, should have determined on future occasions for what imp[ression] to use the name and for which not to use it. Now we said that on certain occasions after having given the definition we did use the word and on others we didn't; but we described these occasions only by saying that we had ‘a certain impression’—that is, we didn't describe them at all. The only thing that characterized them was that we used such and such words. What seemed to be a definition didn't play the role of a definition at all. It did not justify one subsequent use of the word; and all that remains of our private language game is therefore that I sometimes without any particular reason write the word ‘red’ in my diary.57
Here, Wittgenstein states clearly that the diarist, having given ‘S’ to a sensation, must be able to reidentify future sensations as S or not as S. Thus, when in PI 258 Wittgenstein writes ‘But “I impress it on myself” can only mean: this process brings it about that I remember the connexion right in the future’, what he means is that the diarist must be able to reidentify sensation-types.58
3.2 No criterion of correctness
Having established that ‘remembering the connection right’ means reidentifying sensation-types, let us proceed to discuss why Wittgenstein says ‘But in the present case I have no criterion of correctness’, i.e. why there is no criterion of correctness for the diarist to tell whether or not s2 (or any other sensation after the initial baptism) is S.
Wittgenstein himself contrasts the ordinary case of reidentifying sensation-types with the private diary case:
In knowing what seeing red is you seem to say to yourself ‘seeing red is this’—you seem to give yourself a sample but you don't because the usual criteria for the sameness of the sample don't apply. I can say I call ‘red’ always the same color, or whenever I explain ‘red’ I point to a sample of the same color.
Consider the proposition: He makes sure what it means to him by…. Would you say the word had meaning to him if it meant something else every time? And what is the criterion of the same color coming twice?
If we describe a game which he plays with himself, is it relevant that he should use the word ‘red’ for the same color in our sense, or would we also call it a language game if he used it anyhow? Then what is the criterion for using it in the same way? Not merely the connection between “same,” “color,” and “red.”59
In these remarks, Wittgenstein states that in ordinary life one can call an object ‘red’ by pointing a red sample, and say that both the sample and the object are red. In other words, there is a criterion of correctness, it being the sample. He then questions whether the private diarist can ascertain that two private sensations are both of the type red (or S), and whether there is a criterion of correctness in this case.
Wittgenstein's answer, given in PI 258, is that in the diary case there is no criterion of correctness. But why is there no criterion of correctness here? Unfortunately, Wittgenstein does not provide an explicit explanation (either in LPE or in PI). The memory-challenge discussed earlier forces itself on us here again. Why can't the private diarist treat his memory of the initial sensation as a sample (assuming that his memory is reliable for a short period) and use it to judge whether a later sensation is also red (or S)?
In fact, memory of past sensations is essential for public language. Suppose that I am shown a colour sample and am told that it is called ‘red’. I then turn around and see a rose, and I can say that it is red too. In this case, the sample is not in front of me, so I do not compare the rose with the sample directly. What I do is somehow compare my current visual sensation of the rose with my memory of the sensation of the sample, and judge that the rose is red. Memory of past sensations is also indispensable even in the case where one looks at the same sample at different times. Suppose that I hold a red sample in my hand, look at it, blink my eyes and then look at it again. Of course I can say that the sample is still red. But how can I? I must somehow compare my current visual sensation with my memory of the previous visual sensation, and judge that the sample is still red. As for how, I compare these two visual sensations and make a judgment must be a matter of psychology: certain psychological mechanisms must be at work here. I am so constructed that these two visual sensations are of the same nature, i.e. red, to me. Another creature might feel that these two visual sensations are different, perhaps as different as the sensations I get when I look at a rose and then at the blue sky; and it might use two different colour names for them.
It is therefore undeniable that memory of past sensations and certain psychological mechanisms enable us to use the word ‘red’ in ordinary life.60 If they enable our public use of ‘red’, why can't they allow the private diarist to use his private word ‘red’ (or ‘S’)? At t1, the diarist has a sensation s1 and he calls it ‘red’ (or ‘S’), at t2, he still clearly remembers s1, and he now has s2. Can't some psychological mechanisms make s2 and his memory of s1 match so that he judges that s2 is red (or S) too? Here, the diarist is captivated by the analogy between public language and private language, which is the reason why he thinks that his private language is possible. Wittgenstein seems to be aware of this, as he writes: ‘Perhaps a logician will think: The same is the same – how identity is established is a psychological question’.61 But, Wittgenstein apparently disagrees with the logician (or philosopher). He repeatedly asks about how we compare two sensations or images,62 in an attempt to fight against the temptation of the logician (or philosopher) to invoke psychological mechanism to explain the identity between two sensations or images.
There seems to be a strong analogy between the use of ‘red’ in a public language and that of ‘red’ (or ‘S’) in a private language (see the preceding paragraph). But does this analogy really hold? To answer this question, we must first examine what it means to say that two sensations are the same.
‘Two sensations are the same’ can mean two things. One is that two sensations are physically the same, and the other being that they are not physically the same but are qualitatively the same, i.e. they are of the same type. Let us investigate these two cases in turn.
If I look at a red sample at two different times, I get two visual sensations. Can the two sensations be physically identical? It is not unreasonable to understand a visual sensation in terms of activation of neurons in the brain. Is it possible that at these two times, the same neurons in my brain get activated, and are activated to the same degree? It is scarcely possible. One reason is that at these two times the positions of my eyes are highly unlikely to be completely the same, so are the lighting conditions. Another reason is that during the interval, some of neurons which got activated may die, and new ones may emerge. Therefore, it is highly unlikely that on these two occasions the same neurons get activated, and are activated in the same way. This is to say that the two visual sensations are highly unlikely to be the same physically.
High unlikelihood is not the same as logical impossibility. It is logically possible that the two sensations are the same down to every minute detail. But, even if the two sensations are physically the same, no one can really know this. Even if it is discovered, with the most advanced devices, that the same neurons are activated and are activated to the same degree, it is possible that there are still differences that have not been detected by the devices. Without the aid of such devices, it is even more impossible for a person to know that the two sensations are physically the same.
So, it is meaningless to talk about two sensations’ being physically the same. It only makes sense to speak of two sensations as being qualitatively the same, of the same sensation-type. Now, when I look at a red sample at two different times, my visual sensations are physically different. When I look at a red sample and then a rose, my visual sensations are also physically different. But on both occasions I can say ‘I see red’. In doing so, I put the two physically different sensations in the same group, under the same label. As said a few paragraphs back, this cannot be done without memory and certain psychological mechanisms. My having memory of red sensations is due to my seeing physical objects, such as red samples or roses. And my capability to judge two sensations are both red is due to certain psychological mechanisms. Indeed, people do see red; and scientists have, by doing certain experiments on peoples’ visual system on many seeing-red occasions, discovered that humans have colour mechanisms which are sensitive to wavelengths of light and that red corresponds to light with a predominant wavelength of roughly 620–740 nm.
Now, consider the diary case. The private diarist's sensations are severed from the physical world. At t1, he has s1, and t2 he has s2. Since s1 and s2 are physically different, according to what can the diarist say that they are both S? The diarist cannot point to a physical object and say that s1 and s2 are both caused by it. There are no physical objects in this case, which can serve as criteria of correctness. The diarist at this point might appeal to memory of sensations and psychological mechanisms: ‘Memory and certain mechanisms can enable me to judge two visual sensations to be both red, why can't they enable me to judge that s1 and s2 are both S?’ Let us put memory aside for a moment and concentrate on the psychological mechanisms. What psychological mechanisms can be called for? In the case of public language, colour mechanisms can be called for to make colour judgments, tactile mechanisms to judge hardness, coldness, etc., so on and so forth. But in the diary case, are s1 and s2 both visual sensations? Or is one of them is visual and the other a tactile, or one is auditory and the other olfactory? The diarist's private sensations cannot be of such types, otherwise they would be understandable and not private. No psychological mechanisms relating to the known senses can be called for to help the diarist judge whether or not s2 is of the same type as s1.
The private diarist might concede all this. But he might still not surrender. He might believe that there are possibly certain unknown psychological mechanisms inside him that could enable him to reidentify S-sensations. This belief is difficult to remove, for who is to tell that there are no such mechanisms? Scientists have not found such mechanisms, but who is to say that they will definitely not be able to find them in the future? So, it seems that the possibility of private language cannot be ruled out.
To such a problem Wittgenstein's typical treatment is this: it seems to be an empirical problem, but it is actually a grammatical one. In the present case, Wittgenstein's point would be: It seems to be an empirical issue whether there are certain unknown psychological mechanisms for reidentifying S-sensations, but it is actually grammatical nonsense to say that there are such mechanisms. In what follows I shall try to make this point clear.
Elsewhere in PI, Wittgenstein says of the philosopher's tendency to invoke hidden processes and states to explain the meanings of certain words: ‘We talk of processes and states, and leave their nature undecided. Sometime perhaps we'll know more about them – we think’.63 In the same passage, he points out that ‘The decisive movement in the conjuring trick has been made, and it was the very one that seemed to us quite innocent’. The relevance of these remarks to the problem we are tackling here is this: it is tempting to invoke unknown psychological mechanisms to support the idea of private language, but this movement is in fact the main cause of the philosophical puzzlement about private language. It is this movement that turns a grammatical issue into a seemingly empirical one.
Now, why is the statement ‘Certain unknown psychological mechanisms enable one to reidentify S-sensations’ grammatical nonsense? To assume that there are such mechanisms, there must be ways of finding them out. If not, then the assumption would not make any sense; it would be as senseless as the statement ‘He has something. But I don't know whether it is money, or debts, or an empty till’.64 Recall that the private diarist has no outward expressions of his sensations, so when he says that he is having an S-sensation (after the initial baptism), there are no observable signs to help him tell that this is indeed true. He can only appeal to the unknown psychological mechanisms for help, thinking that they can enable him to identify the current sensation as S. So we have a vicious circle here: to find what the unknown mechanisms are we must first make sure that the diarist is indeed having S-sensations on some occasions after the initial baptism, but the latter task is to be done by the unknown mechanisms. Thus, there is no way to find the unknown psychological mechanisms in question, and the statement at the beginning of this paragraph is grammatically senseless.
It might be thought that if inner mechanisms cannot help decide whether the private diarist is re-experiencing S-sensations then external devices can. The thought is this: suppose that there is a device comprising a meter, and some electric poles, which are connected to certain nerve ends in the diarist's brain; then when the diarist says that he is re-experiencing S-sensations, the meter will give certain readings; so the readings on the meter will be able to tell whether the diarist is having an S-sensation or not. This, however, is only wishful thinking. In order for such a device to be constructed, it must be made sure that the diarist does have some S-sensations after the initial naming act; but this is precisely what the device is charged to do. Without knowing for sure that some S-sensations are indeed occurring, one could not even set out to construct the device. The same vicious circle is thus also present in this case.65
The upshot of the above discussion is that no inner mechanisms nor external devices can help the diarist tell whether s2 is of the same type as s1, i.e. whether s2 is also S. Memory is not really an issue here. Even if the diarist had an infallible memory so that at t2 he clearly and correctly remembered s1, there would still be no way for him to know whether or not s1 and s2 are of the same type. So, there is no criterion of correctness in the diary case.
I have just provided an explanation of why there is no criterion of correctness in the private diary case. It shows that the analogy between seeing red in the public case and feeling S in the private case does not work. In Remarks on the Philosophy of Psychology I, Wittgenstein actually thinks about the same issue.66 There Wittgenstein first points out that one can certainly raise his knee three times and say that he has the same sensation three times (a case similar to that of seeing red twice in my explanation), then he asks why one cannot speak of having the same private sensation three times, and finally he states explicitly that the analogy does not work and that the private speaker ‘really does not know, cannot know, which objects are the same in this case’.67 Unfortunately, Wittgenstein there does not explain why the analogy fails to hold. I venture to think that if Wittgenstein were to give an explanation, it would not be too different from the one I just presented.
That there is no criterion of correctness in the diary case has an important consequence. Since there is no way for the diarist to identify later sensations as S or not as S, it is faulty to talk about recording the recurrence of a certain sensation. Wittgenstein explains this as follows:
If we go through with this idea of a private experience which we don't know, we can't talk of a certain private experience either, because this expression is taken from the case in which it alludes to a certain class of experiences which we know – though we don't know which one of its members he has.
One might suggest …: the word ‘t[oothache]’ stands on the one hand for a behavior and on the other hand for a private experience. The connection is that when a man has the priv[ate] exp[erience] he tends to behave in the particular way.
But why should you talk of a priv[ate] exp[erience] and not 100 priv[ate] experiences as you don't know whether there is only one or whether there are 100?68
In the diary case, one might say that the word ‘S’ stands for a private sensation. But why talk of a private sensation and not 100 private sensations? The diarist says that at t1, t2 … he has S-sensations, i.e. that the same sensation S occurs at all these different times. But why not say that he has 100 sensations, e.g. at t1, he has S; at t2, T; at t3 U, etc.? The sensations at all these times are physically different, and there is no way to tell whether they belong to one type or 100 types. Wittgenstein expresses the same point in ‘Notes for the Philosophical Lecture’ (PL hereafter):69
The point is that an essentially private object can't justify the use of a word, neither for the others nor for him. The private object does not only not enter the public game but it can't enter a private game either. You can see this, e.g., if you replace the one private object which is to justify his use of a pain expression by a series of different objects which he has at different times when he says he has pain. “But surely the use of the word pain is based on the fact that he ‘recognises’ his private object as always being the same on those occasions!” What's he mean in this case by being the “same,” or by “recognising”? Neither he nor we have ever learnt to apply these words to his private object. Supposing instead of “he recognises the object” we said more cautiously “he believes he recognises” – but then we ought to say that he believes that he believes he recognises and so on ad inf[initum]. In other words: if this object is as private as we want it to be we have no reason to call it one object rather than 100 objects, we have no reason to apply the word object at all, and no more has he.70
In this remark, Wittgenstein uses the private word ‘pain’ for illustration. Substituting ‘pain’ with ‘S’, the passage says this: if the diarist has s1, s2, s3, etc. at different times, and he writes ‘S’ each time, then there is no way to tell whether these sensations are one object or 100 objects. In other words, there is no way to tell whether these sensations are all of the type S or of 100 different types.
This throws light on the meaning of ‘remembering the connection right in the future’. The diarist wants ‘to keep a diary about the recurrence of a certain sensation’.71 At t1, he has s1, and he calls it ‘S’. He thinks that he has made a connection between ‘S’ and this certain sensation, so that when it occurs again he can also use ‘S’ to refer to it. The problem is with the expression ‘this certain sensation’, as Wittgenstein explains in the above remarks. There is no way for the diarist to tell whether a future sensation is an instance of this certain sensation, or of another certain sensation. This is why Wittgenstein says that the diarist cannot remember the connection right in the future.72
This also casts light on the meaning of a frequently quoted remark by Wittgenstein:
(The temptation to say “I see it like this”, pointing to the same thing for “it” and “this”.) Always get rid of the idea of the private object in this way: assume that it constantly changes, but that you do not notice the change because your memory constantly deceives you.73
Suppose that someone looks for 100 times at an object, which for some miraculous reason constantly changes. Suppose further that he suffers from some memory problems so that he thinks he sees the same object each time. In this case, he might well be tempted to say ‘I see it like this’, or to invent a name, e.g. ‘S’, and say ‘I see S each time’. But here his word ‘this’ or ‘S’ is problematic: grammatically it should refer to a certain object, but in this case 100 objects might have been involved. That there is one object out there, which the person sees at all those times, is an illusion. The diary case is analogous to this. The private diarist thinks that his ‘S’ refers to a private object – a certain sensation. But it is senseless to speak of a certain sensation here. The private object is a grammatical illusion, and it must be got rid of.
3.3 Wittgenstein on private language in LPE and PL
A private language consists of words/names, e.g. ‘S’, in the diary case. The diarist may write ‘S’, ‘T’, ‘U’, ‘V’, ‘W’, etc. in his diary, and these words constitute the language the diarist is using. But is it a language?
This depends on what language is. Since the private language consists of sensation names, the question then becomes whether such names are really names. This then turns on the grammar of ‘name’. On what occasions, under what conditions, would we call a sign a name?
In LPE, Wittgenstein writes:
Consider the proposition: He makes sure what it means to him by…. Would you say the word had meaning to him if it meant something else every time? And what is the criterion of the same color coming twice?
If we describe a game which he plays with himself, is it relevant that he should use the word ‘red’ for the same color in our sense, or would we also call it a language game if he used it anyhow? Then what is the criterion for using it in the same way? Not merely the connection between “same,” “color,” and “red.”74
In these two remarks, Wittgenstein questions the nature of the private diarist's symbol ‘S’ (‘red’, ‘toothache’ or ‘pain’): if the diarist used it without a criterion of correctness, e.g. he used it anyhow, at will, or used it to refer to something else every time, then would we want to call it a name? Of course, the question is supposed to be rhetorical, and Wittgenstein's answer must be: ‘No, we would not want to call it a name’.
So, according to Wittgenstein, a sign is a name only if there is a criterion of correctness for using it. This is a grammatical statement. If the diarist did not have a criterion of correctness for using ‘S’, i.e. if he meant by it something else every time, or used it anyhow, then this sign would simply not count as a name.
From section III.2 above, we know that the diarist has no criterion of correctness for using ‘S’. So ‘S’ is not really a name, and does not deserve to be called a ‘name’, although it looks like a name. As the private language consists of such signs, it looks like a language; but it is not really a language, and does not deserve to be called a ‘language’. Wittgenstein expresses this point as:
And here we are on the brink of a discussion about the language in which someone speaks about his experiences, and which is intelligible only to himself. In this place I shall not enter into this discussion, which belongs to the problems of idealism and solipsism. I wish to say only this much: that here no language is being described at all, even though it appears to be.75
So, private language is an illusion. It is a grammatical illusion, because when we examine what counts as a name or a language, a private name turns out not to be a name, and a private language not to be a language. This is a matter of grammar/logic. This point can be made clearer by considering the following case. Suppose that someone coins a colour name ‘greenred’ to mean ‘red and green all over simultaneously’. But there cannot be such a colour: once the meanings of ‘red’ and ‘green’ are fixed, it is just impossible to talk of greenred, which is a logical/grammatical contradiction. Greenred is therefore a grammatical illusion.76 There can no more be private languages than there can be the colour greenred. In fact, Wittgenstein draws an explicit comparison between the two cases, as he writes:
The ‘private experience’ is a degenerate construction of our grammar (comparable in a sense to tautology and contraction). And this grammatical monster now fools us; … we wish to do away with it …77