Monday, October 31, 2011

Merleau-Ponty's critique of Descartes' cogito

To: Mary J.
From: Geoffrey Klempner
Subject: Merleau-Ponty's critique of Descartes' cogito
Date: 10 October 2005 12:06

Dear Mary,

Thank you for your email of 27 September, with your essay for the Associate Award, 'Doubt, Certainty and Knowledge in the Context of the Critique of Descartes' Cogito in Merleau-Ponty's Phenomenology of Perception.'

This is an excellent piece of work in which I can find very little to disagree with. But I will try.

In terms of the Associate Award, this is well up to the standard required. What I say here should not be taken as a recommendation for making changes or 'improvements' but rather for the sake of philosophical dialogue.

Various things strike me as very familiar (to an English-speaking academic philosopher) about the moves that Merleau-Ponty makes. There are two moves in particular which stand out:

First, there are shades of Wittgenstein in the claim that if I 'doubt the presence of something' I see, then 'neither can I be certain of my thought about that'. Again, the claim that 'the very experiencing of doubting brings a certainty... my act of doubting... occupies me and I am committed to it.'

One of the conclusions that can be drawn from Wittgenstein's considerations concerning a private language is that radical doubt about the validity of perception undermines the very conditions which make it possible for to follow the rule for the words which I use to describe my experiences. Wittgenstein also attacks the professed 'doubts' of the sceptic: a merely imagined doubt, he says, is not a *doubt*.

Again, there are shades of G.E. Moore's 'Refutation of Idealism' and the famous claim 'Here is a is another hand' in the assertion, 'I reassure myself that I see by seeing this or that.' I cannot doubt that what I see is a hand without doubting the very experience itself.

But I am worried about the 'brain in a vat' question and what Merleau-Ponty's response might be to it.

You say, 'If Descartes is correct, all we can know is what is in our own minds; we are sealed within this chamber. In this scenario there is every possibility that we would have the same experience of the world as a 'brain in a vat' as we do with a brain in a body.'

This seems to imply that Merleau-Ponty would flatly deny that I could have the 'same experience' as a brain (or body, what's the difference?) in a vat. In other words, the Matrix scenario is not just unlikely, but inconceivable. If, for one moment, I entertained the thought, 'maybe I am living in a Matrix world', a quick read of Merleau-Ponty would put me straight. If Merleau-Ponty is right, my experience in the Matrix world could not be 'just as' it is in the real world. Something would have to be different. But what, exactly? Or is that the wrong question to ask? If so, why?

I can accept the argument that it is not possible to genuinely entertain these 'doubts' (at least, until people start mysteriously disappearing and reappearing etc. etc.). Yet I want to say that Merleau-Ponty's analysis of embodied experience would simply carry over to the Matrix world. It could be argued that ultimately what matters for Merleau-Ponty is 'experienced embodiment'. An alternative Matrix world in which the subjects were not 'given' bodies but floated around like ghosts - a seeming possibility on Descartes theory - would indeed be inconceivable because the notion of experience and physical action are inextricably bound together.

(If you are curious to research this further, there were 464 references to my 'Merleau-Ponty' + 'brain in a vat' search on Google and 771 entries for 'Merleau-Ponty' + 'The Matrix'.)

You say, at one point, that 'Descartes... was aware of this reality' [that] 'my body is an 'original intentionality', a manner of relating to 'objects of knowledge'. We do not have a thought about the body or have it as an idea, we experience it and through it we experience the world.' Descartes, expresses this thought in his statement, 'I am not lodged in my body as a pilot in a ship.' That says it all. It is the logic of Descartes' argument, the logic that says, 'things could be just as they are for me now if the world was very different from what it is', that leads to the sceptical scenario.

Again, returning to Wittgenstein, one can hear Merleau-Ponty as stating, in response to Descartes, we *do not* doubt. (Wittgenstein: ''Are you not shutting your eyes to doubt?' My eyes are shut.') This is what human knowledge is really about, says Merleau-Ponty. As embodied subjects we are already in the world ('thrown' into it, to use his colourful phrase), and everything starts from that point.

One could say that as an analysis of the structure of knowledge, Descartes approach is fatally flawed because of its 'foundationalist' assumption, that everything must be derivable from an indubitable basis. But this point bears obliquely on the problem of scepticism as such.

All the best,


Defining the problem of solipsism

To: Jim M.
From: Geoffrey Klempner
Subject: Defining the problem of solipsism
Date: 10 October 2005 10:44

Dear Jim,

Thank you for your email of 27 September, with your essay for the Associate Award, 'The Problem of Other Minds'.

This raises the problem of solipsism in a deep way, which goes beyond the academic discussions of the so-called 'problem of other minds'. However, I also feel that you are only half-way there.

Consider this. There seems to be something rather paradoxical about your claim that your sister is (or might be) a 'solipsist' because she is looking forward to the reunion and 'seeing so-and so again', she is unable to appreciate your point of view that the experience would be nauseating and unbearable.

Your sister is looking forward to the reunion, not for self-absorbed reasons (which would be a possibility) but because she feels a genuine desire to see her old friends and acquaintances again. (A self-absorbed reason might be, e.g., if she had 'made it good' and just wanted to bask in the glory of her old friends' admiration or envy.)

True, she hasn't reflected philosophically on what it is to 'meet' someone, or be 'reunited' with them. When she meets old so-and-so who went on to do this-and-that, she will interested, or shocked, or impressed - depending on her own point of view or prejudices - but whatever her reaction, it will be a response triggered by the meeting, a product of two 'realities', hers and that of the other person.

What you say about your sister sounds a bit like the old argument for egoism which goes: 'Whenever you do anything, you do what you want. Doing what you want is acting out of self-interest. So, if you want to help someone, then you are doing what you want, i.e. acting out of self-interest.'

As G.E. Moore once pointed out, this argument is fallacious because it is the essence of the definition of altruistic motivation that one 'wants' to help another person. Doing what you 'want' is, in this case, not self-interested by altruistic. (Once again, there are alternative scenarios e.g. where you 'help' someone only because you expect to get something out of it for yourself, but you lack the self-knowledge to realize this. It would take a lot to show that this is always the case, that whenever we act for apparently altruistic reasons we are self-deceived.)

At the heart of your essay there is an unresolved tension between two very different 'problems' of solipsism. The problem of the thought that one can never know what it is like to be another person, the realization that there exists unbridgeable gulf that separates one consciousness from another, is a popular subject of fiction. Whereas the thought that in a world containing billions of people, 'I am the only real subject' is one that only a philosopher - or a clinical psychopath - would express.

We are in effect dealing here with a 'dialectic' between two different positions: scepticism and anti-realism. Scepticism presupposes realism. I cannot be sceptical about the possibility of knowing other persons, unless I assume to start with that 'other persons' are real and not just a product of my own mind. As products of my own mind (anti-realism) they would be 'knowable', but for that very reason cease to be 'real'.

However, things are more complicated than that, because, as you show, the problem is not a simple 'all-or-nothing' issue. We sympathise, we partially see from another person's point of view, yet there are limits to sympathy - and some are more limited than others. Ultimately, we have to face the terrifying prospect that there is a limit to sympathy or empathy, even for the Saints and Mother Theresas of this world (and there is plenty one could say about Mother Theresa's limited vision). You can go so far, but no further. Ultimately, as the cliche says, 'we are all alone'.

I talked earlier in disparaging terms about the 'problem of other minds' as it appears in much academic philosophy. There are exceptions, which I have mentioned before (like Stanley Cavell). But generally, 'other minds' is seen as a 'problem' for which we are seeking a 'solution', like the problem raised by Hume of scepticism about induction. No-one seriously worries about the fact that there is no proof of the validity of induction. But other minds is not like that. As the many books and novels, and our own experiences testify, every human being has to face up to the challenge of solipsism in one form or another. Even your sister will have had her moments (you might not be aware of this) e.g. when someone she thought of as a 'best friend' turned on her, or maybe when she tries to puzzle out your behaviour.

What would be a real treatment - a genuine treatment - of the problem of solipsism, in philosophical terms? I don't know of any philosopher who has done this successfully. Cavell, Sartre, Levinas are all important, but there is still much that needs to be said. Maybe you have something to say that can take things forward, even if this only means asking questions which have not been asked before.

All the best,


Thursday, October 27, 2011

Making sense of time

To: Robert H.
From: Geoffrey Klempner
Subject: Making sense of time
Date: 5 October 2005 12:39

Dear Bob,

Thank you for your email of 27 September, with your Associate essay entitled, 'What Time is it Anyway?'

Like you, I am gripped by the problem of time, and specifically, the problem of finding a way to grasp, or explain the nature of McTaggart's A-series.

Amongst analytic philosophers, I would guess the majority would agree with Putnam that the only question that needs to be addressed is the nature of physical time. In his book, 'Real Time', D.H. Mellor argues that time is completely accounted for by the B-series. All the things that we want to say about the 'now' or about the distinction between past, present and future can be accounted for in terms of the B-series.

To give you a sense of what Mellor means, I will give the example of 'now'.

Mellor would offer the following as a logical analysis of the meaning of the concept, 'now':

The time is now XYZ if, and only if the time at which 'the time is now XYZ' is uttered is XYZ.

How does this work as an analysis?

On the left hand of the 'if and only if', there is a statement which uses the word 'now', while on the right hand side there is a statement which merely *quotes* the word 'now'.

As I write this, it is 12.01 pm British time. I can assert, truly, the following statement:

The time is now 3.33 pm if and only if the time at which 'The time is now 3.33 pm' is uttered (or written) is 3.33 pm.

Both sides of this equation are false, therefore the equation is true. If the left hand side had been true (if it had been 3.33 and not 12.01) then the right hand side would have been true also, so again the equation would have been true.

What is noticeable about this is the way the word 'now' seems to lose its essential meaning in referring to *now*, and just means any time you say the word 'now'. Every time is a 'now'. Now is just one now amongst billions of nows. Nothing special about it at all.

Intuitively, we feel this to be wrong. Now is different from all other nows, because it is actual, real, happening and not just a now that has already happened or has yet to happen. The difficulty is - and this is the difficulty that philosophers like Mellor and Putnam latch onto - is that whatever words you use in attempting to say what you mean by 'now' or the 'nowness of now' fail to accomplish their intended purpose. Whenever you attempt to describe *now*, the actual now, all you end up doing is describe some now. Your description is just as valid for any of the billions of nows that make up the history of the universe.

The sound of eight bells is no different from the position of clock hands or the shadow on a sun dial. It is physical event. We measure time, as you say, by comparing one process with another - the process of a clock, or the earth travelling round the sun. However, it could be argued that the *experience* of 'hearing eight bells', unlike the experience of just seeing the position of the hands on a clock or the shadow on a sundial, does capture something extra which the objective account of time in terms of the B-series is unable to explain. This seems to be the point of Husserl's essay on the phenomenology of time consciousness. But what is this experience?

To hear eight bells involves memory. But memory is not the same as a mental tape recorder. If I tape the sound of a clock striking eight, then the 'memory' or information stored on the magnetic tape still has to be played to be accessed; and it is the playing of it, rather than the storing of the information on tape (or in the brain) which constitutes the essence of temporal experience. What is it to hear the the 'dong' not just as a dong but as the third dong? How is the experience of its being the third dong presented to the mind? This is essentially the same question as the question how it is that we are able to hear a particular note from a tune as the note from that tune and not just, say, any old middle C.

It is a long time since I looked at Godel. Reichenbach was concerned with the 'arrow of time'. (He wrote a book with this title.) According to the B-series view, it is irrelevant which direction time is 'flowing' because time is just a static series of events. All the laws of physics can be reformulated to describe a universe where time travels backwards - e.g. where human beings are formed in the earth, then get younger and younger until the time comes to enter their mothers' wombs etc. etc.

Is that the case, or is there some extra fact about the physical universe, which has not been taken into account? The idea of a 'backwards universe' seems fantastical. Yet all that apparently distinguishes the 'forwards' and 'backwards' universes is the laws of probability, as exemplified in the Second Law of Thermodynamics. It is extremely improbable, but not physically impossible, that all the air molecules in this room will in the next second go in the same direction - towards the door - and I will be left gasping in a vacuum.

It might seem that conscious time - the A-series - is essentially unidirectional. But that hasn't stopped science fiction writers exploring the idea of what it would be like to live in the backwards universe. I remember reading a story with this theme but can't recall the author. Mind-bending stuff.

In your last paragraph, you raise the question whether, or how, a better understanding of subjective time would impact on abnormal psychology. It is plausible to say that for someone traumatised by an early experience in their childhood, there seems to be an inability to allow that this experience exists in the past. Bad things happen, and life goes on. Yet for some, it appears that life has stopped at that point, and they are condemned to endlessly act out the same scenario.

All the best,


Is knowledge justified true belief?

To: Francis M.
From: Geoffrey Klempner
Subject: Is knowledge justified true belief?
Date: 29 September 2005

Dear Frank,

Thank you for your email of 18 September, with your University of London essay in response to the question, 'Is knowledge justified true belief?'

This is a very good piece of work which would be pushing towards a first (a mark in the 70's) in the exam. I would evaluate it as borderline.

The question about justified true belief is very well trodden ground, and to make an impression you have to show that you have at least attempted to gain a wider perspective on the moves and counter-moves.

Lehrer effectively does this in staking a claim about the 'goal of defining knowledge'. Asking about the goal or point of a definition is always a good thing to do when you are attempting a philosophical analysis. One question one might raise, however, is what is the assumption behind the idea of asking for the goal or point of a definition?

Naively, one might thing that we just have this concept of knowledge, and the aim of seeking a definition or analysis is to learn more about what that concept actually is. Whereas Lehrer's approach implies that everything is up for grabs, the aim is not so much to explain 'our' concept of knowledge - whatever that might be - but rather to create one, more or less from scratch. 'What would be a good concept of knowledge? Whatever that is, I'll take it, thank you very much.'

Along similar lines, I have seen one author approach the problem of free will by posing the question of 'Varieties of free will worth wanting.'

This implies that accepted linguistic usage is not adequate, on its own, as the ultimate court of appeal in questions of philosophical analysis. Philosophers are responsible for moulding and refining concepts, replacing vague or partially incoherent concepts with concepts which are sharper, clearer, ultimately more useful.

One might be forgiven for thinking that Gettier could have saved himself the trouble of writing his article if only he had read Russell. In deciding whether A knows that P, we need to look at each the beliefs involved in the justification which A would give for his belief that P. Provided that there are no false beliefs somewhere along the way - and of course provided P is true - then P counts as knowledge.

The problem with this as a recipe for 'obtaining truth and avoiding error' is that this is a recipe for perpetual suspension of judgement concerning whether someone *really* knows that something is the case or not. It is impossible in practice to investigate all the implicit assumptions behind the judgement that P is the case. In Gettier terms, you have to consider all the extravagant and improbable ways in which it might turn out that the connection between the truth of what is believed and the believer's justification is merely accidental.

Arguably, this is a problem with any of the refinements proposed to the 'justified true belief' definition. As soon as you try to plug the gaps created by Gettier, the spectre of scepticism looms.

By contrast, the 'justified true belief' definition is perfectly workable in practice. Is P true? Yes. Can A give a plausible justification for his belief? Yes. That's good enough for most purposes. Most of the time, following that formula, we will indeed obtain knowledge and avoid error with respect to claims about what this or that person knows.

As soon as one tries to plug the gaps, however, everything is thrown into confusion.

In other words, in responding to the genuine concerns raised by Gettier to the naive cut-and-dried definition of knowledge as justified true belief, we find ourselves pushed in the direction of a rather more questionable definition of knowledge - questionable because of the way that it resurrects the spectre of scepticism.

Obviously, what you want to do in these circumstances is not simply retreat to the naive definition of knowledge, but rather combine the 'best' response to Gettier with a robust defence against scepticism. I have my own views about this, but that's another story.

I think that, if you were looking for ways in which your essay could be further improved, then the scepticism issue would certainly be one valid issue to explore.

Another, related point concerns the 'third person' nature of the definitions of knowledge, whether we are talking of the original naive version, or the various Gettier-inspired versions. The assumption is that 'we' have knowledge, we are capable of deciding with confidence whether a given proposition is true, and the only question is how to decide whether or when to attribute knowledge to others. This relates to the debate between 'reliabilism' and 'foundationalism', another of the issues which you will be exploring for the Epistemology paper.

All the best,


Wednesday, October 26, 2011

Metaphysics: its methods and subject matter

To: Kathleen C.
From: Geoffrey Klempner
Subject: Metaphysics: its methods and subject matter
Date: 29 September 2005 11:03

Dear Kay,

Thank you for your email of 18 September, with your first essay for the Metaphysics program, in response to the question, 'What is metaphysics? Is there anything special about the methods of metaphysics or about its subject matter? Illustrate your answer with one example of a metaphysical problem or controversy.'

This is an excellent piece of work. I am so glad that you are reading D.W. Hamlyn's 'Metaphysics' - his book has clearly helped you focus in a way which you would not have been able to do relying on my notes alone.

'Metaphysics... seeks what applies to any conscious beings in any world they consider real, even though the experience of finding reality real could be quite different for conscious beings in worlds with different natural circumstances.' - This is interesting, because of its deliberate vagueness and open-endedness. In the Critique of Pure Reason, after describing our human 'forms of intuition' as spatial and temporal, Kant leaves open the question whether there might be creatures who experienced reality through forms of intuition different from ours, even though we (necessarily - because we are bound by our own forms of intuition) lack the capacity to imagine what such experience would be like.

I remember Hamlyn making this point in a Metaphysics lecture when I was doing my BA. For me it was one of those weird, scary moments when you know that a door has been opened and yet there is no way to see what is on the other side of that door. All you know is that it is something indescribable and unimaginable.

It is sad that there are so few opportunities these days for philosophy students to have that experience.

Your conclusion, however, is that 'metaphysics seeks a general principle of the apprehension of reality, but not Reality, with a capital 'R'.' In other words, what we term 'reality' is always and necessarily local, parochial. What, then, of the grand project of 'defining Reality' (with a capital 'R')?

As I have tried to show in various ways, one has to make that extra step, even though you have every reason to believe that what you are seeking to do is impossible: to look through the door, get above the mundane world, take in the whole of Reality (capital 'R') not just a part of it. So, for me, the crucial arguments are those which revolve around this very attempt, even if the attempt is ultimately doomed to failure.

As to the methods of metaphysics, I agree up to a point that none is peculiar to metaphysics. However, as you will see later on in the program, I am prepared to use, or at least attempt methods of argument (which loosely come under Hamlyn's heading 'dialectical proof') whose validity is not cut and dried. So an additional element of judgement is involved, an appeal to 'intelligibility' which cannot be further justified.

Here's a schematic account of what I mean. Let's say that in investigating a certain problem - say the problem of idealism as illustrated by Berkeley's theory - you find that you have reached a point where two mutually contradictory theories seem equally defensible, but where there appears no possible way, in principle, of deciding between one view and the other. Then my conclusion is that BOTH theories must be wrong.

In claiming this I am taking the lead from Kant in the Antinomies of Pure Reason in part II of the Critique of Pure Reason). Kant already has his 'theory', he has already reached the conclusion he wants to reach in the first part of the Critique. So his treatment of the Antinomies (e.g. 'The world has a beginning in time' vs 'The world has no beginning in time') is merely a diagnosis, an interpretation which helps illustrate the theory.

However, I am prepared to go one step further and use my (alleged) antinomy as the premise in an argument whose conclusion is the rejection of the (alleged) assumption which leads to the antinomy. - When you reach that argument you will have to judge for yourself whether you think it is valid or not.

One statement which you make for which you do not offer any support is, 'It is difficult to accept the position that Berkeley gives God in his philosophy.' Why, exactly? Because it is difficult to believe in God? or because Berkeley makes his 'God' work too hard? Or is it rather that we are the one's - the finite spirits - which it is hardest to find room for in Berkeley's 'world inside God's mind'?

You conclude that it is 'unlikely that there will ever be definitive answers'. After 33 years of study (the Hamlyn lecture I referred to was back in my 4th year) I am glad to report that I am not yet prepared to accept this.

All the best,


Nietzsche and Bergson compared

To: Robert H.
From: Geoffrey Klempner
Subject: Nietzsche and Bergson compared
Date: 28 September 2005 14:56

Dear Bob,

Thank you for your email of 18 September, with your essay for the Associate Award, 'Nietzsche and Bergson'.

I do not feel that you have succeeded in connecting Nietzsche and Bergson in the way you wanted to do.

Let me say to start with that I agree that there are several areas where these two philosophers may be fruitfully compared/ contrasted.

One area is the influence on both philosophers of Darwin's theory of evolution. Another aspect which impresses me is their theories of time. Both of these you mention. But merely mentioning an aspect or a topic isn't enough. You need to delve more deeply into the problem and make a case.

Either topic would be sufficient for an essay.

Evolution is central to Bergson's metaphysics. Whereas, for Nietzsche, the fundamental lesson of evolution is epistemological - our way of seeing the world, the concepts which we use to classify things are the product of our evolutionary past and not timeless 'forms' as Plato believed. The contrast is quite vivid, between Bergson's metaphysical vision of the universe as a product of 'creative evolution' and Nietzsche's sceptical argument against a Platonic view of concepts.

Again, both philosophers make much of time, but the their interest is very different. Bergson is famous for his theory of 'duree', his emphatic assertion that temporal becoming and not the historical order of events is the very essence of time. This is a metaphysical claim. Nietzsche, as you mention, is famous for his theory of the eternal recurrence. This was not his original theory but derived from the Stoics. Although Nietzsche attempted to give a physical 'proof' of the eternal recurrence theory, his main concern was moral, i.e. with values. The crucial test of your existence is whether you can will that this moment should be repeated over and over again, or, whether, on the contrary the idea of the eternal recurrence would crush you and reduce you to despair.

I will pick up on another comparison you make, where you state that a 'feature shared by both is that their philosophies tend toward anti-intellectualism.' Phrased in this way, the claim is very misleading. Both philosophers are criticising a particular view of the intellect, but the aim, and the target of criticism is very different in each case.

For example, Bergson, in arguing for the reality of temporal becoming, criticizes what he terms the 'cinematographic' conception of time, the futile attempt, as he sees it, to logically analyse time into a succession of static states. The intellect is the culprit in this case, because it is being misused. The flow of time is an example of something which is real but cannot be analysed. However, it does not follow (and it did not follow for Bergson) that the intellect does not have a perfectly valid application in other areas.

Nietzsche, in developing his sceptical arguments against the Platonic model of knowledge, is concerned to show that the intellect is not a separate, spiritual force but part and parcel of our physical nature. Of all philosophers, I would say that Nietzsche had the most stringent intellectual conscience, and the highest regard for the human intellect. He is not 'anti-intellectual' but rather anti a particular false view of what the intellect is.

My general feeling from reading this essay, and your previous essays, is that you have attempted to cover too much ground in too small a space. If you enjoy Nietzsche then I recommend that you read ONE book by Nietzsche. To take one example, Genealogy of Morals, which consists of three extended essays would be a good choice because in this work Nietzsche focuses on clearly identified objectives.

Having studied the book closely (i.e. read it not one but several times, writing copiously in the margin) pick a topic and write an essay on that. Try if you can to formulate a precise question. It is also a good idea to read secondary literature, such as Kaufmann's fine book 'Nietzsche: Philosopher, Psychologist, Antichrist' and also look for relevant material on the internet.

You will learn more this way, not less. For a start, you will learn how to write a philosophical essay. This is something that has to be learned (as many of my students will testify) even if you are an old hand at writing articles and essays. Students who have read and enjoyed philosophy for years still come unstuck when it comes to putting thoughts down on paper.

All the best,


Tuesday, October 25, 2011

Mind-body problem and the concept of identity

To: Walter F.
From: Geoffrey Klempner
Subject: Mind-body problem and the concept of identity
Date: 28 September 2005 10:50

Dear Walter,

Thank you for your email of 14 September, with your second essay for the Philosophy of Mind program, in response to the question, 'What is identity? What is the relevance of a definition of identity to the problem of the relation between mind and body?'

Although rather short and condensed, this is a well thought out essay which manages to touch on many key issues surrounding the question of the proposed 'identity' between mind and body.

'You say, There are no identity criteria that allow us to say that mind and body are either entirely separate or entirely the same.' - The first question to ask is, what exactly is a 'criterion of identity' (or what are 'criteria of identity')? Why do we need identity criteria when there is a perfectly good logical definition of identity in the formula, 'A=B if and only if everything true of A is true of B and vice versa' (Leibniz Law)?

One can assert the 'identity' of anything with anything. Make up whatever concepts you like. My ear and the moon. If my ear is the moon then everything true of my ear is true of the moon and vice versa. The fact remains that nothing that Neil Armstrong did in his famous moon walk has any discoverable relation to the state of my ear, nor is a rock circling the world a quarter of a million miles away affected in any way when I get earache.

More to the point - and this is where Wittgenstein's considerations on language become relevant - there is no way anyone could learn the concept 'my ear and the moon' without first acquiring the concepts 'ear' and 'moon' and then artificially sticking the two together to make a composite 'object'.

In a similar way, putting 'my sensation of red' and 'brain event E' together and calling it a single 'mental event' does not make one out of two. Nothing turns on the distinction (as you note) between an ever-so-close relationship between my sensation of red and brain event E, and the identity of my sensation and the brain event. In other words, asserting 'identity' is just an empty mouthing of words.

In these terms, it looks as though we have no choice but to embrace some form of dualism. The assertion of 'identity' is empty, meaningless.

However, something you say in your last paragraph points to a different solution. It is one thing to talk of 'mind' and 'body'. It is perfectly reasonable to take the view that psychology (the science of minds) is irreducible to physics (the science of bodies). The different scientific disciplines cut up the world in different ways, but this is fully consistent with saying that all that ultimately exists are physical entities. As a simple illustration of non-reducibility, there is no physical explanation, in terms of atomic structure, why you can't put a square peg in a round hole.

It is something entirely different when we identify mind with peculiar 'objects' like 'my red sensation'. It does not follow from the fact that people enjoy sensations of red, that there exist 'mental objects' which can be identified in a Cartesian manner independently of how things are in the physical world. The point of Wittgenstein's argument against a private language is that there are no such 'private objects'. There are only statements that we make, whose truth conditions necessarily refer to both first- and third-person criteria, to what both I and others are able to know.

If there are no ontologically independent 'mental objects' then the question of the identity or non-identity of such objects with physical objects or events does not even arise.

That is where many philosophers would leave the problem. Of course, the Wittgensteinian move does not save us from the hard work of explaining how the mental arises from the physical. However, I am thinking of a different problem. Granted that the phenomenon of consciousness as such can be 'explained' (as Dennett believes) there remains the seemingly intractable question of what it means to have THIS unique point of view, what it means to *be* GK, or WF, or TN. In other words, Nagel's problem of the meaning of 'I'.

I have struggled with this in my book Naive Metaphysics, and also towards the end of the Philosophy of Mind program. But I don't have a 'solution'. It seems to me that there is no room for a 'theory' here. There is nothing to 'explain'. There is only the sheer inexplicable fact - as Descartes recognized but perhaps failed to see the full significance of - that I exist.

All the best,


Are possible worlds really real?

To: Katherine A.
From: Geoffrey Klempner
Subject: Are possible worlds really real?
Date: 26 September 2005 13:33

Dear Katherine,

Thank you for your email of 13 September, with your first essay for the Possible World Machine, in response to the question, 'Are Possible Worlds Really Real?'

I liked your example of the newsagent with the one remaining copy of Philosophy Now, and all the different ways in which you might have not found out about Pathways.

One question you raise is whether it is really the case that you might not have purchased a copy of Philosophy Now. As you correctly anticipate, the fatalist would say, No. According to the fatalist, everything that happens in the world had to happen as it did, for the simple reason is that any statement which we make about the future already has a truth value.

The fatalist will say that the day before you purchased a copy of Philosophy of Now, it was true that in a day's time you would purchase a copy of Philosophy Now. A thousand years before you purchased a copy of Philosophy Now it was true that in a thousand years time you would purchase a copy.

For the fatalist, the future is just as much a matter of fact as the past. The only difference is we do not know the future until it happens.

In these terms, one cannot even raise the question about possible worlds. Nothing is 'possible' except what actually happens. There are no 'possible but not actual' worlds, so it is empty to raise the question whether such worlds would be real, really real, or unreal.

But suppose we 'bracket' the question of fatalism. Bracketing is something that philosophers do to focus on a specific problem. Let's say we don't know whether fatalism is true or false, but the problem we are investigating is how we should view possible worlds if fatalism is false.

If fatalism is false, then it is possible that you might not have purchased a copy of Philosophy Now. What does that statement mean? What are the conditions under which that statement would be true?

This is a problem which has been much debated by contemporary philosophers. One plausible view is that a 'possible world' is just a description, something made out of words which we might read in a book. 'Katherine decided not to visit the newsagent.' When we talk about possible worlds we are just talking about situations which we create out of words which do not correspond to what actually happened. Another view, similar to this, is that a 'possible world' is just a situation you picture in your mind, perhaps when you read words in a book, or perhaps one which you create yourself. In your mind is the scenario of your glancing at the newsagent shop and deciding that you do not have time to go in.

A difficulty raised for this approach in unit 1 is that statements which we make about things that might have been are regarded as true or false. A statement is true or false depending on the facts. Statements about what actually happened are made true or false by facts about the actual world, therefore statements about what might have happened are made true or false by facts about worlds other than the actual world. - Is that a good argument?

According to one of the strongest defenders of the 'reality' of possible worlds, David Lewis, the 'KA' who might have passed by the newsagent shop is not you but your 'counterpart'. She is very much like you, but she exists in another possible world and you exist in this world. This meets your objection against being a 'player in several possible worlds at the same time'.

But in what sense can we talk about a single, 'actual' world? You make a valid point that for all practical purposes there is not one world by many worlds - arguably, a world for each individual person. No two personal 'worlds' are exactly the same. What is interesting about this idea is that makes a rather neat parallel with what we want to say about the relation between 'the' actual world and other possible worlds.

Every personal world is equally 'real', but only one personal world is 'my world'. The difference between 'my world' and 'your world' is merely one of perspective. I am already inside my world, whereas I can only get inside yours by making an effort of sympathetic imagination. Similarly, Lewis argues, every possible world is equally 'real', but only one possible world is 'our world'. We are already inside the actual world, whereas we have to make an effort of sympathetic imagination to get inside other possible worlds, e.g. the world where you passed by the newsagent, or the world where Hurricane Katrina blew itself out before it reached the coast.

But are these worlds which we imagine 'really real' or do they just exist in our heads? Many people would prefer to believe that one 'real' world is enough. I am dissatisfied with both alternatives. I believe in possibilities - real possibilities and not just pictures which we make in our heads or words which we write on paper - but real possibility is not just another kind of 'actuality', which would be the case if we accepted Lewises theory.

All the best,


Monday, October 24, 2011

Marcus Aurelius and melancholy

To: Gregory G.
From: Geoffrey Klempner
Subject: Marcus Aurelius and melancholy
Date: 7 September 2005 16:48

Dear Greg,

Thank you for your email of 26 August, with the latest version of the beginning part of your dissertation for the ISFP Fellowship on The Art of Melancholy.

I enjoyed reading this. But you don't want to hear praise, you just want to hear the truth, right? :)

Seriously, there are some issues that I would like to raise (I hope I won't be repeating myself, I never look back at letters I've written, even a week ago) which may have a bearing on the direction of this piece.

Although I have not experienced clinical depression, I will risk take issue with what you say about depression, which does have a central bearing on your thesis.

As a matter of logic, there are two ways in which the assumptions underlying our naturally optimistic view of life might be 'reversed'. They can be reversed into pessimism, as you say here. But another form of reversal - arguably closer to the experience of pure depression, as opposed to extreme anxiety - is simply to see things without any colouring, negative or positive. One should not underestimate how devastating this can be. Our naturally optimistic view of life functions as a self-fulfilling prophecy. We take on challenges and succeed because we believe that we will succeed. This implies two things, a probability of success but also, crucially, that there is such a thing as 'success', itself a state with positive attributes.

Seen from this perspective, what is so striking about the philosophy of Marcus Aurelius is the constant emphasis on seeing things just as they are, clearing away all false assumptions, consoling fantasies, so that the plain facts stand revealed in their gruesome nakedness. Remind yourself that this person pisses and shits. Or that the greatest 'pleasure' is just a momentary physical spasm.

The crucial difference from the depressive, is that Aurelius does have a reason for action: his duty, determined by his station in life. In between the times when duty calls, he puts his spare mental capacity to work on itself, improving and refining his own mental abilities.

In discussing the question of providence, I was surprised that you make no mention of Aurelius' agnosticism. As I have mentioned before (and I think you agreed) more than once, he argues, 'If there is a God then..., but if all that exists is material atoms then... Either way...'. You can't count on providence if there is no way of knowing if the universe is not just an accidental collocation of atoms.

I don't even know if Aurelius makes that much of living in accordance with nature. How can we know what that requires, if we don't even know what 'nature' is? All that his stoic knows is reason and control: control over one's body and control over one's own thoughts. Pleasure is nothing, but neither is pain.

Aurelius never gets there. The battle for physical and mental control is never won. That's one of the things that makes the Meditations such fascinating reading. Someone who was convinced wouldn't need so many arguments, would they?

Paradoxically, Aurelius delights in wielding his analytical knife. There is a kind of glee, the glee of a schoolboy cutting a worm into pieces to watch them wiggle. Not so much cruelty as sheer fascination. The world is full of fascinating things for the seeker after truth, and Aurelius saw more of the world than most.

I fully agree that the Meditations are much more than just a set of spiritual exercises. They are a chronicle of a real person's life. I would go further and say that they are a historical document which we enjoy because it enables us to enter vicariously into the life of a great historical figure.

What this is leading up to, I guess, is a question about how we can reasonably expect 'virtue' to relate to 'happiness' in Aurelius' world view. Reading the Meditations, I find it hard to picture the author as a 'melancholic man', partly for reasons which I have stated. He enjoys the sheer energy generated by heavy philosophizing too much. Like the addicted jogger or weight trainer, he gets high on mental endorphins. Nor is there any evidence of pain or struggle in the way he writes (you may disagree with this). It just all comes out.

Of course, it is another question for the reader whether there is any message you can take away about the relation between virtue and happiness. If you don't enjoy writing, if you're crap at philosophy - AND there's no God - maybe there's not much hope after all.

A point of interpretation: The quote which begins, 'Bear in mind constantly that all of this has happened before...', ends, 'only the people are different'. As Timothy Sprigge emphasises in the chapter on Nietzsche in his excellent little book 'Theories of Existence' the whole point about the eternal recurrence is that it will be YOU who comes back, not merely someone ever so much like you. (On this point I disagree with Sprigge and agree with Aurelius.)

A point of 'fine tuning'. This is a piece about Aurelius. Of course, the context of Stoicism generally and great figures such as Epictetus will also be prominent. But once or twice it seemed to me as if you had momentarily forgotten that Aurelius is the one occupying centre stage. I don't think you need to alter the structure of your argument in any way. As I said, it's a matter of tuning - a word here, a phrase there.

On a practical note, there are words in brackets which refuse to translate on my Mac, so I just get this: (?????????) or sometimes this (π?????????). I have a Greek font, but the PC to Mac translating program refuses to reproduce any letter apart from π.

Keep up the great work!

All the best,


How do you know the author of these words has a mind?

To: Denis C.
From: Geoffrey Klempner
Subject: How do you know the author of these words has a mind?
Date: 1 September 2005 13:51

Dear Denis,

Before I launch into my comments on your second essay for Possible World Machine, you might enjoy the following link:

(Postmodern Essay Generator)

If you try the essay generator a few times, you will notice certain patterns re-appearing. Without too much difficulty, you could probably deduce the transformation rules which were used to generate the essay from a random selection of philosophical terms, grammatical constructions, philosophers names and names of other well known figures. (My 'essay' was a baffling but strangely intriguing little piece about Madonna's use of sexual symbolism.)

When I am writing letters to students, I am conscious of the temptation to repeat what I have said to another student about the same essay topic. I have learned to spot standard 'essay types'. However, I always try to look for something different in the essay I am commenting on, something different to say even when the essay reads much like a dozen essays I have read before.

In your case, surprisingly, although this has been quite a popular essay topic you are the first to consider the idea of essay-writing authorware. All the other answers I can recall have launched into the 'problem of other minds' without considering the particular implications of the way the question is worded. (Well done for that.)

Two preliminary points. There is a subtle (or not-so subtle) kink to the question, and also to your answer. What critics of postmodern philosophy like the physicist Alan Sokal are basically saying is that postmodern writer's *do not* have minds, at least, not when they are 'generating' their postmodern writings. They have merely learned how to throw words and phrases around, stick them together in a semblance of a text with meaning, but all they have succeeded in doing is fool themselves and their readers.

There is no mention in your essay of the Turing Test, which might be thought to be the starting point for an answer. The Turing Test essentially relies on interaction between the terminal producing words and the intelligent viewer. You do mention interaction in the context of what Sartre says about a literary work. However, this is not interaction in the sense that Turing proposed: it is not analogous to a process of formulating a hypothesis, designing an experiment (putting a question to the terminal) and testing the hypothesis against the result of the experiment.

So let us assume, as you have done, that the phrase 'these words' in the essay question refers to a substantial piece of writing, a few thousand rather than a few hundred words. In fact, however long the piece of writing, there is always the slight probability that it could have been produced completely randomly (as, it is said, a monkey hitting keys at random would eventually produce the works of Shakespeare). But for practical purposes we can discount that possibility.

The hypothesized 'authorware' does not simply generate words at random, but strings them together in apparently meaningful sentences - like the postmodern essay generator, but much more skilfully. And it does this reliably.

However, an equally important consideration is that the authorware is not an artificial intelligence. If it were, then by definition we would be dealing with a 'mind' (for the purposes of this question - as you have mainly interpreted it - we can discount the dualist worry that no merely physical entity can have a mind).

- I wonder if you can see where this is going?

The transformation rules used for the postmodern essay generator are relatively easy to spot. It might take a few sheets of A4 to write them all down. By contrast, the program for the philosophical AI runs to hundreds of thousands or possibly millions of pages.

In both cases, however, we are dealing with rules, a program. What is the *essential* difference? is there one?

On my Macintosh, I have a piece of software, Orville, based on the 'Eliza' program. Here is a 'dialogue' which I have just had with Orville:

'Good afternoon... please state your problem.'
'I'm writing a letter to Denis.'
'How long have you been writing a letter to Denis?'
'About half an hour.'
'What else?'
'I'm finding it difficult.'
'Did you come to me because you are finding it difficult?'
'How can I help?'
'Tell me what to write.'
'Have you asked such questions before?'
'I'm amazingly intuitive.'

The great thing about Orville is that in a folder all the transformation rules are written out. The text is not very long. If I had the time and energy, I could probably do a lot better. However, however hard I worked at polishing the script, things will quickly come unstuck with questions like, 'Tell me what to write.'

This illustrates the essential difference between an AI program - supposing that one could be written - and a set of linguistic transformation rules, however complex. The difference is one of level. So long as we are merely dealing with words and their combination and recombination, all that can ever be produced is mimicry. The rules for a genuine AI program would have to generate the very capacity for language. We can't simply take words ready made and invent some clever way of shuffling them around.

If that is the underlying structure that we are looking for, a subject with the capacity for language, how can we tell? My answer would be that it depends on whether we are dealing with a good piece of philosophical writing or not. In bad philosophical writing - and this is essentially Sokal's point - it does seem that you could have substituted any one of half a dozen different phrases and it wouldn't have made any difference, whereas in a good piece of philosophical writing, each sentence, each paragraph seems necessary in the light of what went before. That is something only a mind can do.

All the best,


Thursday, October 20, 2011

Leucippus and Democritus on atoms and the void

To: Marcus S.
From: Geoffrey Klempner
Subject: Leucippus and Democritus on atoms and the void
Date: 30 August 2005 11:52

Dear Marcus,

Thank you for your email of 18 August, with your fourth essay for the Presocratics program in response to the question, "'All that exists is atoms and the void.' What is an atom? What is the void?'

[Correction: the question should have said, 'All that exists is atoms and the void.']

You have made a great go at the argument. Even though you say you found the essay 'very difficult' you must have enjoyed writing it. You have demonstrated your willingness to consider the question from first principles without any preconceptions - just as the Greek atomists did.

As you have interpreted the question, *if* all that exists is atoms and the void what *must* 'atoms' and 'the void' be? There are other ways of approaching the question: for example, by considering the historical context, viz. Parmenides views on Being and reactions to it. However, your approach is not only legitimate but also very fruitful.

You say that there must be at least two atoms. It is difficult to argue with that: 'atoms' means more than one atom.

Next, you consider three alleged alternatives: that atoms constitute less than half, half, or more than half of 'all that exists'. This seems to make logical sense. On the assumption that the void has no mass or weight (which, strictly speaking, if we were considering every aspect of the question deserves to be argued for and not just assumed), it would seem that the only measure is volume: i.e. atoms constitute less than half, half or more than half the total volume of 'all that exists'

However, if, as you go on to argue, the void is infinite (i.e. of infinite volume), then the only way that atoms could constitute half, or more than half, of all that exists is if either there are an infinite number of finite atoms, or there exists one or more infinite atoms.

- At this point we need to pause to consider the logic of infinity. The natural numbers 1,2,3,4,... constitute an infinite set. So do the even numbers, 2,4,6,8,... even though there are only 'half as many' even numbers. Mathematicians define an 'infinite set' as a set whose members can be put into a 1-1 correlation with a 'proper subset', i.e. some but not all of the members of that set. As an illustration of this, consider a galactic hotel with an infinite number of rooms. A party arrives consisting of an infinite number of new guests. That poses no problem. The occupant of room number 1 is asked to move to room number 2, the occupant of room number 2 is asked to move to room number 4 - and so on. Then the new party all take the odd numbered rooms.

See the Wikipedia article:'s_paradox_of_the_Grand_Hotel

Back to your essay.

You say, 'The expression 'all' then means the same thing as the 'void'. The 'void' is 'all.' Thus, the word 'all' is superfluous.' Suppose we are attempting an inventory of reality, which takes account of everything that exists. For example, the atomists' inventory would be very simple:


The problem with this is that in putting forward this list there is another statement, implied but not made: that this is indeed 'all'. As an illustration of this, suppose someone handed you a class list for your new course on Hamlet. The class list doesn't tell you everything you want to know: is this *all* the students who will be attending the class? in other words, is the list exhaustive, or is it possible that more students will be joining later?

So, in terms of the atomist theory:

There are atoms
There is one void
There is nothing else

In stating that there is nothing else, we are considering everything, both atoms and void. Any x that we come across must either be an atom or the void. The quantifier 'Any x' refers to an unspecified 'domain of quantification', rather than just to the void. (You can look up these terms in any modern introduction to logic.)

Moving on, in what sense can there be a 'clump' of atoms? As you observe, we must always be able to logically distinguish two atoms from one atom. There is a serious issue of how exactly this is done. Must there be an infinitely small void in between two atoms? Or could two atoms be fully in contact, yet distinguished from one another by the possibility of sliding, i.e. by the fact that one atom had the capacity to move relative to the second atom?

You go on to say, 'Atoms might be an infinite distance from each other, therefore the void must be greater than infinite in size.' At first sight, this might look like a case for applying the principle I referred to earlier, in relation to Hilbert's paradox of the infinite hotel. If you 'add' all the even numbers to all the odd numbers the result is the same 'size' as the original two sets. viz. infinite. However, in the case of spatial infinity, it is not clear what would be meant by saying that A is at an infinite distance from B, which is at an infinite distance from C, where A, B and C are in a straight line (whatever that means in this context). Is C the same distance (i.e. infinite) from A as the distance of B from A?

I'm going to pass on that one. The theory that atoms exist in an infinite void does not require that some atoms are infinitely far apart. I just don't know what it would mean to say that two finite objects A and B are separated by an infinite spatial distance, whereas I think I know what would be meant by saying that the void is of infinite size.

Atoms, or clumps of atoms, might be of infinitesimal size, i.e. be infinitely small. However, it doesn't follow from the assumption that the void is infinite, that there exist atoms or clumps of atoms of infinitesimal size. You might be tempted to argue, 'Compared to the size of the void, any finite object would be infinitesimally small,' but that doesn't follow.

You conclude, 'I am going to be speculative and conclude that logically speaking the assumption [that all that exists is atoms and the void] cannot be accurate because it fails to describe the universe as it actually is.' An atomist would be justified in asking what gives you the right to conclude this? Certainly, experience tells us that there must be more than two atoms and the void. However, that empirical observation does not refute the statement that all that exists is atoms and the void, or require us to qualify that statement in any way.

All the best,


Descartes' argument in the 6th Meditation

To: Eleftherios A.
From: Geoffrey Klempner
Subject: Descartes' argument in the 6th Meditation
Date: 30 August 2005 10:10

Dear Eleftherios,

Thank you for your email of 20 August, with your second essay for the Philosophy of Mind program, in response to the question, 'Examine Descartes' argument, in the Sixth Meditation, for the distinction between mind and body. What objections can you conceive being raised against the argument? How would you attempt to defend the argument against those objections?'

The core of Descartes argument, as presented in the 6th Meditation is the principle that if it is possible to 'conceive clearly and distinctly one thing without another', then the two things must be separate substances, in the logical sense: even if the two substances are always found together, 'they can be placed in existence separately, at least by the omnipotence of God'.

This is what Descartes asserts to hold of 'my body' and 'myself as a thinking thing'. Is his argument valid?

Before I consider the objections which you raise, we have to look at the context of the argument: why does Descartes think that he can conceive of my body and my thinking self apart from one another?

It can't just be a matter of personal observation, because then an objector could simply say, 'Well, I can't conceive this!' End of argument. However, the clear and distinct ideas concerning mind and body are not simply given; they are the outcome of the argument which Descartes considers in Meditation 1, namely, the possibility that I as a thinking subject can exist in a universe where the only thing that exists apart from my mind is the evil demon who causes me to have illusory ideas of a material world.

If an objector says, 'How do you know that?' then all that Descartes can say is that the hypothesis makes sense, i.e. that he has a 'clear and distinct idea' of it.

The appeal to 'what an omnipotent God can separate' is merely used to underline the logic of identity and separateness. Descartes is not saying, 'my mind and body are separate because God can separate them'. That is not his argument. So far as the argument for mind-body dualism is concerned, God's existence is only required in the sense that the very possibility of philosophical argument depends on our being able to trust our powers of reason, which Descartes thinks is only possible if there is proof of a non-deceiving God.

Your first major objection is that 'if God created a miracle by separating body and mind, we wouldn’t be able to say anything about the relationship between mind and body in the real world for they are the result of a miracle'. It could be argued that this is precisely what Descartes believes. Mind-body interaction is miraculous, we can't explain it. We only know that it must occur. However, there is more to say on this, as we shall see below.

Your second major objection is partially met by the observation that Descartes offers an argument (the evil demon argument) for the separability of mind and body and does not merely rely on his intuition that they are separable. However, the objector is justified in replying that the same objection applies to the evil demon thought experiment. The thought experiment seems to be coherent, we seem to have a 'clear and distinct' idea of it, but we could be wrong. This is what contemporary critics of Descartes would say.

As a matter of interest, there was a popular view in the 60's which originated with the 'Australian materialists' Armstrong and Smart, which attempted to side-step the question whether mind can exist apart from body, and asserted that, from a scientific point of view, the best explanation of our experience is a 'contingent identity' between mind and body: in other words, granting the evil demon possibility, but rejecting the claim that this shows that mind and body are not, as a matter of contingent fact, identical. In 'Naming and Necessity' (Blackwell) Saul Kripke demolished this view with a brilliant argument, vindicating Descartes' claim that *if* mind and body can exist separately (i.e. if the exist separately in some possible world or worlds) then they cannot 'in fact' be identical.

Following on from your first major objection you consider the difficulty in maintaining the view that there exists an organ (the conarium or 'pineal gland') where mind and body interact. I agree with your objection here. However, it is worth pointing out that Cartesian physics differs crucially from Newtonian mechanics in allowing for the change of direction of 'animal spirits' without any input of energy. This is because Cartesian physics is based purely on the analysis of geometrical extension - a feature which Leibniz heavily criticized on the grounds that it failed to account for 'force' and 'impenetrability'.

Do the alleged facts of parapsychology go any way towards mitigating the objections to Descartes' argument? I think we would have to say that if telepathy, or telekinesis, or out of body phenomena were conclusively verified in a laboratory, then this shows that there is something we do not understand about the workings of the physical world, i.e. particles or forces which have up to now escaped physical observation. I would not be a vindication of Descartes view that mind and body are logically distinct substances.

All the best,


Wednesday, October 19, 2011

Does thought precede language?

To: Saud S.
From: Geoffrey Klempner
Subject: Does thought precede language?
Date: 25 August 2005 11:59

Dear Saud,

Thank you for your email of 18 August, with your second essay for the Philosophy of Language program, entitled, 'Does Thought Precede Language?'

This is a fine piece of work, which deals with themes that I find, personally, very gripping.

It is not really a response to the question posed in the second set of essay questions (5. Does thought entail the possession of language?) but perhaps you did not intend it to be. The central issue, for you (as for me) concerns the nature and definition of reality: which is the fundamental question of metaphysics.

The idea that the private language argument, far from being a true liberation merely exchanges one 'demon' for another is familiar to students of Wittgenstein. David Pears has a two volume study of Wittgenstein entitled 'The Language Prison'. The later Wittgenstein has been described as a 'linguistic idealist'. Michael Dummett, expositor of Frege and enthusiastic student of Wittgenstein's philosophy claims to have derived his account of an 'anti-realist theory of meaning' from Wittgenstein's later writings, in particular, the seminal doctrine that 'meaning is use'.

It is typical of this kind of situation in philosophy that what those on one side see as liberation, those on the other see as a trap, or a prison. However, to describe this simply as a clash between 'anti-realists' and 'realists' (in Dummett's sense) seems to lose something of the essence of what you are talking about here.

The idea that we were once in direct communion with 'reality' and have subsequently fallen from grace is not a new theme in philosophy. Plato's theory of recollection is one famous version of the theory. So long as we remain in mortal bodies, Socrates argues in the Phaedo, we can only have incomplete knowledge of the eternal forms with which the soul once communed in its previous life. That is why the true philosopher longs for death.

The nineteenth century British idealist, F.H. Bradley, in his treatise 'Appearance and Reality', describes a tri-partite scheme, where starting from initial, pre-conceptual contact with Being, human thought and language dismembers the world using the apparatus of terms and relations. The job of metaphysics is to demonstrate how our concepts necessarily falsify reality, and to present a vision of the Absolute where all contradictions are finally overcome.

What Lacan is describing seems very similar to Bradley's vision.

The intriguing question is whether there can be any room - in our new-fangled linguistic philosophy - for speaking intelligibly of the 'Mystical' or the unity of Being (if indeed these are ultimately one and the same).

Interestingly - and this strengthens the Lacan connection - in his book on Bradley, Richard Wollheim speculates that there is a Kleinian explanation underlying Bradley's approach to metaphysics. According to Klein's theory, the infant responds to its first experiences of frustration by 'splitting' the 'good mother' from the 'bad mother', the 'good breast' from the 'bad breast'. This leads to anxiety, which can only be overcome by restoring 'whole objects'. This is the pattern which underlies feeling remorse for wrong doing and acts of reparation in adult human relationships. There is a compelling parallel with Bradley's theory of the Absolute.

The later Wittgenstein did not abandon his view that there were things beyond language: like ethics, aesthetics or our sense of the religious. In the works published after his death there is clear evidence of his interest. But unless one can find the appropriate language this is not much better than looking out through the bars of ones prison cell at a distant beyond. 'What you can't say you can't say, and you can't whistle it either', as C.D. Broad said about the Tractatus.

There is no doubt that the rejection of Cartesian epistemology is a 'liberation'. Even the fiercest critics of Wittgenstein's later philosophy do not suggest that we turn back the clock. The question for debate is whether we have, as Scruton claims, finally gained our freedom, or have merely exchanged one prison for another.

My response is to refuse to consider the question in these terms. There is a long road towards 'emancipation' - whatever that might mean - and no-one has the right to state dogmatically how far along that road we are. We can only philosophize from where we stand now. The time has gone when one could pose grand questions in metaphysics and then give a give a conclusive answer. Even Bradley, with his lofty vision of metaphysics, described his approach as 'sceptical'. He gives very little positive information about his Absolute.

Philosophy of Language is less popular now than it was in the 70's. Fashion, or the 'state of the art' now dictates that philosophers expend their energies on the philosophy of mind, where, we are told, the real breakthroughs are to be made. Personally, I'm not convinced.

All the best,


Descartes and the problem of mind-body interaction

To: Daniel R.
From: Geoffrey Klempner
Subject: Descartes and the problem of mind-body interaction
Date: 24 August 2005 11:57

Dear Dan,

Thank you for your email of 16 August, with your University of London BA essay in response to the question, 'Is Descartes right to assert that there is a real distinction between mind and body? Does the distinction leave Descartes with insoluble problems about their interaction?'

In response to the first part of the question, you give a careful analysis of the arguments Descartes deploys in asserting the real distinction between mind and body, pointing out the non-sequiturs. You also offer a more general diagnosis of what has gone wrong ('moving from a subjective epistemological claim to an objective ontology', 'move from imagining this situation to proving that it is necessarily the case').

I think an examiner would be justified in feeling that you had not directly answered the question, 'Is Descartes right to assert that three is a real distinction...?', but instead answered a different question, 'Does Descartes argue validly for a real distinction...?' There are dualists who would argue that Descartes' arguments are invalid as they are stated in the Meditations, but they can be patched up, fixed to appear much more formidable.

When looking at any historical philosopher, this is always an option to take into consideration. Some times, though not always, it is legitimate to claim that the extra premisses were 'implicit' in the text.

(Reading this through a second time, it has occurred to me that there is an ambiguity in the question - which you would be perfectly justified in pointing out. On one reading, if dualism is true, then whatever you think of Descartes arguments in the Meditations he is right to assert what he asserts. On the other reading, if Descartes argued invalidly, then he was not right in asserting what he asserted, even if what he said was true. The fact that it is raining doesn't make it right for me to assert that it is raining even if what I said is 'right', if there was no way I could have known that it was raining.)

At the end of the day, the 'beefed-up' arguments for dualism can be defeated - as some would claim, by using Wittgenstein's destructive critique of the notion of a 'private language'. But that's hard work. Reading your essay, it is difficult to get a sense of the powerful attraction of the dualist vision.

In other words, I guess what I missed here was some recognition of the 'grippingness' of Descartes vision. He is not just some historical philosopher who committed a curious fallacy which other thinkers have unfortunately replicated.

Kripke's argument is directed against materialist philosophers like Armstrong and Smart who in your terms exploit the 'ignorance' gap between subjective certainty and objective ontology. It does not follow from the possibility of imagining my mind existing in a non-material reality alone with the evil demon, that my mind is not, as a matter of brute contingent fact, identical with matter.

However, as Arnaud's objection shows, there is another possible strategy for defending materialism which does not depend on the claim of contingent identity, namely, to demonstrate - just as Pythagoras demonstrated the properties of the right angled triangle - that the very notion of experience necessarily involves the existence of a material world: in other words, what Descartes claims to imagine is not really conceivable after all.

Regarding interaction, neither the point about the pilot and the ship, nor the careful analysis of how false beliefs arise really address the difficulty.

Descartes claims that interaction - if it occurs - is fully consistent with the subjective experience of being an agent in a physical world. And I think on this he is right. The point about false belief is relevant to the question which is very worrying for Descartes but less so for us, of how a non-deceiving God can permit any false beliefs to arise.

However, a relevant consideration which you might have considered, which arises in relation to Leibniz's criticisms of Descartes, is that in Cartesian physics mind-body interaction does not violate conservation principles. Cartesian physics is based on the a priori analysis of extension alone. No energy is required, Descartes thought, simply to 'divert' the animal spirits in a different direction.

For Descartes, the only problem is the non-location of mind: lacking physical attributes, mind cannot occupy space or be at one place rather than another. However, as the exchange with Elizabeth seems to indicate, he would reply that the phenomena of magnetism or gravity show that physical contact is not required for causal interaction.

All the best,


Tuesday, October 18, 2011

Hume on personal identity

To: David F.
From: Geoffrey Klempner
Subject: Hume on personal identity
Date: 24 August 2005 10:19

Dear David,

Thank you for your email of 15 August, with your first essay for the Possible World Machine, and for your 2 emails of 22 August with further comments.

Hume's remark ('For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other...') occurs in the part of the Treatise dealing with 'Sceptical and Other Systems of Philosophy' (section VI. 'Of Personal Identity'), where he also argues that - from a philosophical point of view - no meaning can be attached to the notion of the 'distinct and continued existence of objects'.

Hume begins the section on personal identity by noting, 'There are some philosophers, who imagine we are every moment intimately conscious of what we call our SELF; that we feel its existence and its continuance in existence...'.

This is important, because it helps locate the dialectical context of Hume's remark.

In the earlier section II, 'Of Scepticism With Regard to the Senses' the scepticism in question is scepticism concerning the very meaning of the claim that objects 'continue' to exist when not perceived and 'distinct' from the act of perception. It's not simply that we don't know or can't prove this. And similarly, with the soul, the question is not simply, 'Here we have this idea of a soul, now, can we prove that souls exist or not?' but rather, 'What are these philosophers are talking about? - I haven't the faintest idea!' So it would not be correct to say, as you do, that 'Hume is not arguing against the existence of the soul'.

Of course, Hume is being disingenuous. He does know. Just as (when he goes off to play a game of backgammon) he knows what spatio-temporal objects are. In his official philosophy these are 'fictions', psychological constructs, not concepts that can be justified by reason or logic. We psychologically can't help attributing our thoughts, feelings and sensations to a 'self' which 'has' them, but if we just look at the plain facts of experience - instead of the mental pictures that we are tempted to construct - there's nothing there to see.

A much better candidate for agnosticism about the soul would be Locke. In his treatment of personal identity, Locke proposes a 'soul swap' thought experiment. During the night the souls of a prince and a pauper are exchanged, while their memories remain unaffected. So the prince still thinks he is a prince, the pauper still thinks he is a pauper. What this shows is that the soul hypothesis is otiose. Whereas according to Hume it is meaningless.

You are right to point out that Hume is not arguing against a dualist view of the mental. It might seem that a materialist would be saved from the 'bizarre implications' because you can simply identify the self with something we don't see when we look inside ourselves, namely our own brain. With his 'sceptical' view of the nature of physical objects, that option is not open to Hume.

What about the bizarre idea that 'I' do not exist while asleep? Hume has a logical answer to the question of the definition of 'I' which is astoundingly simple. All the 'ideas' and 'impressions' in the universe are neatly partitioned into sets which are *present* to one another at a given time. No two sets overlap. You and I can have similar feelings but as a matter of logic we can't share numerically the same feeling - not even if we were telepathic. My sense of identity over time is simply a product of continuity between the present set of co-present ideas and impressions and my memories ('ideas') of previous co-present sets. In this logical sense, I do 'exist' while asleep.

Hume's great contribution to philosophy - as he saw it - was his 'science of human nature', or, as we would call it, psychology. He would have been enthusiastically in favour of research on the concept formation of infants (cf your note 3). Concepts are formed through the association of ideas, concepts which when examined by the philosopher, i.e. logically, prove to be mere 'fictions'. All the treatises that have been written about the soul, god or the ultimate destiny of man are fit only for committing to the flames.

Further thoughts

'Consciousness'. Hume lumps thoughts, feelings, sensations and concepts all under the heading of 'impressions and ideas'. That is the given. It is in relation to this given that sceptical questions (concerning 'external' objects, or a 'self') are raised. It would be nonsensical for Hume to question whether ideas and impressions exist. (I don't believe he ever refers to the notion of 'consciousness'.)

There are lots of 'dualisms'. Cartesian interactionism, Spinozist dual-aspect theory, epiphenomenalism, parallelism...

- Then there's my so-called 'theory', the dualism of subjective and objective worlds.

There are still some defenders of idealism (your preferred solution to the mind-body problem). Foster, in 'The Case for Idealism' in one of his arguments uses Cartesian idea that 'things would be for me just as they are now if material objects don't exist'. If that is true, then, as Berkeley argued, matter is simply redundant.

Nothing you say here reminds me of anything that Strawson has written. There is a short piece by Strawson, 'Self, Mind and Body' which very entertainingly pokes holes through the Cartesian notion of a soul. Strawson claims that since there are no criteria of identity for souls, there is no logical difference between my having one soul or a thousand souls. This is similar to Kant's argument in the 'Paralogisms of transcendental psychology' (from Part II of Critique of Pure Reason) that there would be no difference between having one soul or a sequence of souls each communicating its states to the next like a line of colliding billiard balls.

On earthworms. Suppose Hitler's brain was preserved by an evil scientist, and a section was mashed up and injected into your skull. You wake up thinking you are Hitler. Under what circumstances would it be true to say that, as a result of this operation, you are Hitler? Or, what if this was done to a dozen people? would there be a dozen Hitlers?

There's more discussion of these kinds of thought experiment in the unit on personal identity.

All the best,


Review of Naive Metaphysics

To: Chris E.
From: Geoffrey Klempner
Subject: Review of Naive Metaphysics
Date: 22 August 2005 14:48

Dear Chris,

Thank you for your email of 6 August, with your essay for the Associate Program, 'Objective and Subjective - Some Thoughts on Naive Metaphysics'.

At the core of your essay there is a criticism which I want to agree with - or at least want to understand - concerning the impossibility of saying 'this' and 'meaning' it in the sense in which it is intended to be meant. I would not want to rule out the possibility that this criticism defeats my two-world theory. There is not much I can say about this, however, because I don't know how you would reformulate the criticism in the light of what I say, below.

The problem is that your exposition is seriously hampered, if not vitiated, by a misconception concerning the role of the thought experiment of the table lamp and the apple.

The description looks very much like what you might find in a book defending the sense datum theory of perception: e.g. H.H. Price's thought experiment of the tomato in his book 'Perception'. In fact, the role of the description very different. It is not intended as a coherent description of a possible experience, but rather gives voice to what someone in the grip of a certain picture of the subjective might be tempted to say. It is not just incoherent but flagrantly so.

As such, I agree with your criticisms. The crucial question is where the critique of the naive experiment leads us.

It is my contention that Kant had just such a naive picture in mind as his target when he wrote his 'Refutation of Idealism' (from the Second Edition of the Critique of Pure Reason). That is to say, according to Kant, the question raised by Descartes concerning the existence of an external world (how do I know I'm not being fed dreams by an evil demon) assumes that we are given an 'I' and a stream of experiences, the question being whether or not these experiences correspond to something external, i.e. space-occupying matter. Kant's argument, in one sentence, is that a subject with an identity over time is possible only on the condition that the objects of its perceptions are spatio-temporal.

Kant described his theory as 'empirical realism' and 'transcendental idealism' - as I would describe it, a version of nonegocentrism. In some manner which Kant never explains - in fact, he is emphatic that it can't be explained - noumenal reality gives rise to spatio-temporally located 'subjects' and 'objects'. We cannot know anything about noumena. All we can know is what is given in experience - together with the a priori knowledge of the necessary form of such experience. But Kant never dwells on the nature of this 'we', or on the relation between 'I' and 'we'.

My interest, however, is in a theory which a critic of Kant might be tempted to construct on the basis of the Refutation of Idealism, basically, a theory of phenomena without noumena, or 'transcendental egocentrism'.

According to transcendental egocentrism, there are no 'subjective objects'. The only objects that it recognizes are things like apples and lamps. 'Intuition' cannot be described other than in terms of such objective concepts. Pains and tickles, or sensations of colour or taste are not 'objects' in their own right. Rather, the truth of statements about these mental items is parasitic on the truth of statements about spatio-temporal objects.

Like naive egocentrism, transcendental egocentrism is incoherent - but, if you like, in a more interesting way. It is incoherent because the fundamental elements of reality - Kantian 'intuition' and 'concepts' - when taken as necessary and sufficient for the construction of an objective world, require a transcendental ego which cannot be wrong about the standards it uses to judge whether a given statement about the world - a given subsumption of intuitions under concepts - is true or false. Without the third person standpoint, I argue, there cannot be such a thing as 'truth'. (This argument is basically a re-run of Wittgenstein's argument against the possibility of a private language.)

That's how I arrive at nonegocentrism. It is a different route from Kant, and the result is different. Instead of a world of noumena, we just get 'more of the same'.

Now the crucial bit. We've rejected naive and transcendental egocentrism. Now it's time to reject nonegocentrism. This is where I use a different set of thought experiments (the story of my doppelganger) designed to massage the intuition that there is a difference between there being someone like GK in the world, and *my* being GK. I critique Nagel, who seems to be merely sitting on the fence, unable to decide between several inadequate interpretations of the meaning of 'I am TN'.

I fully agree that where we want to end up is 'I recognize that I am the object of your point of view, as you are of mine'. However, there is one vital difference. This is what brings my two-world theory much closer to Emmanuel Levinas (see his classic work 'Totality and Infinity') than Nagel. In Nagel's universe, the end result is 'two of the same'. This is how (along with most analytic philosophers) he poses the problem of other minds, and is also (in 'The Possibility of Altruism') his solution to the question of the objective basis for moral conduct.

In the two-world theory, by contrast, the reality of the other consists, not in their 'sameness' but in their 'absolute otherness'. I will always be 'the one asking the question'. The other will always be that in virtue of which there is such a thing as truth. Without truth, there can be no reality. But, equally, there has to be someone, myself, asking the question in order for this theory to make sense.

I suspect that my way of developing the argument is naive when compared to someone like Levinas. I am looking for a 'proof', where, perhaps, no proof is to be found. But that's where I'm stuck.

All the best,


Monday, October 17, 2011

Difficulties for a materialist view of the mind

To: Denis C.
From: Geoffrey Klempner
Subject: Difficulties for a materialist view of the mind
Date: 9 August 2005 12:44

Dear Denis,

Thank you for your email of 30 July, with your first essay for Pathways Introduction to Philosophy, in response to the question, 'What difficulties stand in the way of a materialist view of the mind, according to which thoughts, feelings and sensations are ultimately nothing more than processes in the brain?'

You have an interesting take on this. In view of the fact that the human brain is immensely complex, and given our present limited state of knowledge, there is no reason to think that there will be any difficulty in ultimately accounting for the phenomena of consciousness, thoughts and emotions in materialist terms. Even telepathy, you speculate, may eventually be explained as a physical phenomenon.

However, this still leaves various kinds of experiences described as 'supernatural' such as out-of-body experiences, ghostly apparitions, astral projection and precognition. There is also the belief in life-after-death to account for.

You ask, 'Why should a materialist need to take these ideas into account?' A good question.

A hard line materialist will challenge reports of so-called supernatural experiences, and reject any belief in life after death. (Although, interestingly, Daniel Dennett in 'Consciousness Explained' argues that if the human mind is just 'software' running on 'hardware' then it might be possible to upload my brain program onto disc before I die and then download it into a new body - which would be a form of 'immortality'.)

An alternative, less sceptical line would be to admit that there may exist, after all, another realm apart from the material/ physical, which one might call 'non-physical'. However, as you argue, this non-physical world would in effect become part of the 'physical' world, because 'there has to be a transfer of energy between the two worlds for any interaction to occur.'

In other words, someone who argues, on the basis of unexplained phenomena, that there is more to the world than the physical processes we are familiar with may, for all we know, be right.

That would be a form of 'dualism'. My feeling is that the traditional dualist will not be happy with this conclusion. The main sticking point for the traditional dualist is the difficulty in accepting that any physical explanation of consciousness would suffice to show that the self is ultimately part of the physical world, irrespective of what one includes under the label 'physical'.

Imagine a future world where the existence of mind-stuff has been scientifically demonstrated. In addition to protons, neutrons and electrons, a new entity has been discovered, the 'menton'. Mentons are extremely difficult to detect. The main effect which they have on the physical world is via the human brain. However, based on a model of the human brain, menton-detectors have recently been constructed.

Now a new problem appears in the philosophy class room. Instead of the question, 'Am I just protons, neutrons and electrons?', students now ask, 'Am I just protons, neutrons, electrons and mentons'?

Descartes' argument for mind-body dualism (Meditation 6) can be run just as well for a 'physical world' which includes mentons. Even if an evil demon is deceiving me into thinking that a physical world exists, when in fact no physical world exists, I know that I exist. Therefore what 'I' refers to cannot be physical.

According to the epiphenomenalist who rejects Cartesian mind-body interaction (on the grounds that it violates the conservation of energy) there could be an individual physically just like me, but who did not have *this* inside - my 'zombie doppelganger'. The fact that the menton detector is able to prove that my zombie doppelganger has mentons is not sufficient to show that what I have inside - the indescribable quality of consciousness - is present in my doppelganger also.

Another way of expressing the epiphenomenalist's doubts would be to point out that any physical explanation only explains other physical phenomena. An explanation of the brain processes involved in the experience of perceiving a red patch, for example, might account for the experimental subject's utterance, 'I see a red patch', or the subject's ability to pick out red objects from objects of various colours. The explanation can never get to the 'raw feel' itself.

What these - admittedly rather dubious - arguments indicate is that there are some philosophers who are likely to remain sceptical about materialism, even if neuroscience makes great steps forward.

All the best,


What is the mind-body problem?

To: Walter F.
From: Geoffrey Klempner
Subject: What is the mind-body problem?
Date: 22 July 2005 11:55

Dear Walter,

Thank you for your email of 12 July, with your first essay for the Philosophy of Mind program, in response to the question, 'What is philosophy? Illustrate your answer using the example of the mind-body problem.'

A good question to start with would be, What is the mind-body problem? why is there a problem concerning the relation between body and mind?

You remark that dualism is a 'doctrine that nobody holds but everybody practices'. In Daniel Dennett's book 'Consciousness Explained' there is a nice cartoon of a professor at a blackboard writing a very long equation, which comes to an abrupt end. 'Then a miracle occurs.' The philosophical joke is that not a few researchers working in the field of neuroscience make the tacit dualist assumption that somehow, when enough machinery gets going, mind just 'appears'. They assume the very thing that needs to be 'explained'.

As a matter of fact - contrary to what you assumed - there has been an increasing rapprochement between philosophy of language and linguistics - very much against the spirit of Wittgenstein (who famously remarked, in relation to the nascent science of psychology, that there are 'experimental methods and conceptual confusion'.) Some theoretical physicists now openly brag of doing 'experimental metaphysics' - which shocks me even more.

Freud is an interesting case. Frank Sulloway in his long and learned biography (which I have only dipped into) attributes to Freud a 'biology of the mind', where the drives are seen as quasi-physical forces. Yet Freud's therapeutic practice belied this mechanistic view of the human mind. What seems to be true, and important, is that our history goes far back beyond the time when apes first walked upright and developed a language. We are not just physical entities, but physical products of blind evolution occurring over hundreds of thousands of years, which has left us with an unhappy, or at least ambivalent inheritance - something human beings would not have if we were designed by God 'from scratch'. While we try to rationalise our situation, in reality we are driven by forces that we barely comprehend.

There is surprisingly little concern for this aspect of the human situation in modern functionalist philosophy of mind (as exemplified, e.g. in Dennett's work). You would think that all it took to make a conscious subject was a sophisticated computational capacity - forgetting that we are agents who act for a purpose, and purpose is not something that can just be invented, out of the blue.

I wonder whether the 'functionalism' you refer to bears anything more than a passing resemblance to Dennett's brand of functionalism. Dennett's starting point is the intuitive idea that whatever brains do to produce thoughts, feelings and consciousness is in some sense independent of the 'stuff' that brains are made of. The same structure, composed of different stuff, would accomplish the very same purpose.

So, for example, it might be possible for a Martian, whose body is based on silicon chemistry, to have the thought, 'Earth is the third planet from the Sun', and this would be the same thought as my thought that 'Earth is the third planet from the Sun' even though seen through an electron microscope (as it were) something very different was going on at the purely physical level. What matters is the 'software' or 'program', not the hardware.

Hence the alarming idea that, if all I am is a program, then it ought to be possible to 'upload the GK program' onto a super-computer, then 'download' it into a new body - or dozens, or thousands of bodies.

I have tried to imagine what point is being made by the claim that 'psychotherapy is an invasive procedure'. Here is my best guess. Full frontal lobotomy is an invasive procedure because it physically alters the structure of the brain. If you think of the mind in biological terms, as Freud was tempted to do, then it looks as though the 'talking cure' is non-invasive because it leaves the biology intact. But if the essence of mind is not in its biology but in its functional organization described in psychological terms, then the psychotherapeutic approach alters the structure of the mind itself, and so, in its way, is just as 'invasive' as surgery.

I agree with you and Khashaba that philosophy is fundamentally different from science. But history has shown that philosophy has always learned from science, and benefited from that knowledge - even at times, like the present, when philosophers fall into the trap of attempting to imitate scientists.

All the best,


Friday, October 14, 2011

Zeno's paradox of Achilles and the tortoise

To: Marcus S.
From: Geoffrey Klempner
Subject: Zeno's paradox of Achilles and the tortoise
Date: 1 July 2005 09:59

Dear Marcus,

Thank you for your email of 20 June, with your third essay for the Ancient Philosophy program, in response to the question, 'Analyze in detail any one of Zeno's paradoxes.' You have chosen to analyze the paradox of Achilles and the tortoise.

Achilles does catch the tortoise - you are in no doubt about that. So the question for you is, What is the most plausible reading of Zeno's argument? how can we explain why the argument is felt to be gripping, rather than a trivial sophism? This could be described as an example of the application of the 'principle of charity' in philosophical interpretation. An interpretation is more believable if it makes the philosopher out to be someone worth reckoning with, rather than a fool.

However, I must stop you there. Because Zeno believed - if Plato's account in the Parmenides is correct - that Achilles does not catch the tortoise. No-one catches anything, because nothing moves, nothing changes in Parmenides' One. That is because any attempt to describe a differentiated or changing world leads to self-contradiction. Which is precisely the proposition which Zeno sets out to prove in his paradoxes.

That is not such an absurd claim. We are aware that language is a rather vague, imprecise tool. Perhaps it is true that although we get along with words for practical purposes, any attempt to describe the world with logical rigour will break down. It is not inconceivable (at least, prior to looking at the detailed arguments) that the philosopher who is concerned with the question, 'What is Reality?' in the absolute sense which demands logical rigour might be led to the conclusion that the world we 'know', the world of 'practical purposes' is not Reality, but merely a dreamlike half-world where 'mortals wander, two-headed, knowing nothing'.

You make a robust attempt to explain the assumptions which lead Zeno to this conclusion. If Achilles and the tortoise are conceived as mathematical points, and if Achilles stops at every half-way point (or if the godlike observer who has set up this experiment stops him) then Achilles cannot catch the tortoise. - But they are not, and he doesn't, so he can.

In your last paragraph, you develop this idea by adding a more general explanation, in terms of Parmenides' conception of the 'oneness' of the world: 'Such a world has absolute boundaries for reality.' The implication is that Parmenides was wrong, because in reality there are no absolute boundaries.

There is a paradox which has attracted the attention of contemporary philosophers which you may have heard of: the paradox of the heap. Or, as I prefer, the elephant paradox. A one ounce elephant is a small elephant. Agree? OK. If you add one ounce to an elephant which is not a large elephant, then the resulting elephant cannot be a large elephant. Agree?

It logically follows, that - according to you - there are no large elephants! (The argument is by an application of the method of mathematical induction. If you can prove that 1 has mathematical property X, and prove that *if* n has X *then* n+1 has X', then it logically follows that all numbers have X.)

One plausible response to this paradox is to claim that Reality cannot be vague, only our descriptions of it. It follows that there must be some way to describe any elephant which does not involve any vague predicates. - But are you so sure that such a description can be found? And what happens to the 'elephant' meanwhile? (The problem of vagueness is one of the major themes in the early and later philosophies of Wittgenstein, which we will be looking at in the Pathways Philosophy of Language program.)

I did feel that in your (not implausible) explanation of how motion occurs in an 'infinite world' (which I take to mean a world where there are no fixed boundaries) you glossed over an aspect of the 'grippingness' of Zeno's paradox. It is in fact the case, that in the process of catching up with and overtaking the tortoise, Achilles does an infinite number of things. He does actually get half-way, and half-way again, and again... to infinity. That is not such an easy proposition to accept. If I said to you, 'Do you know, I have the power to do an infinite number of things!' your first reaction ought to be pretty sceptical. But, in fact, by just reaching to my CD recorder to put in the next blank disc I have done just that.

Motion, which we all take for granted, is a pretty scary concept because it implies infinity, and infinity is scary. Zeno was the first thinker to realize, and really appreciate, this fact.

All the best,