Monday, March 24, 2014

Descartes' argument for the mind-body distinction

To: Emelie G.
From: Geoffrey Klempner
Subject: Descartes' argument for the mind-body distinction
Date: 8th December 2011 11:55

Dear Emelie,

Thank you for your email of 4 December, with your essay for the University of London BA Modern Philosophy: Descartes, Locke, Berkeley and Hume module, in response to the question, 'What did Descartes mean when he said that there is a real distinction between the mind and the body? Describe and critically evaluate the arguments he gave for this thesis.'

This is an excellent piece of detective work, in which you make every effort to uncover the basis for Descartes' claim that there is a real distinction between the mind and the body, in order to evaluate the validity of his argument.

As you state, the matter is left open in Meditation 2 (or, at least, that is what Descartes concedes to Hobbes), and it is not until Meditation 6 that Descartes considers that he is in a position to offer a definitive argument. As you comment, 'And this must mean that God must be involved.' Yet, what Descartes actually says in the important passage is that two things are separate if it is possible in principle for them to be separated, 'if only by the power of God'.

The objection you raise to this is that if the eternal truths are 'products of God's will' then there are lots of things God can do, such as create 'a square apart from four sides'. In other words, if the connection between mind and body is as close as the connection between a square and four sides, that is as close as anyone would wish to get to a proof of monism, God notwithstanding.

Did Descartes think that God could create a square without four sides? Frankly, I don't know what this would mean and I don't think Descartes did either. However, this is missing the point in a sense. Two things which we cannot separate might yet be separate in reality, i.e. logically distinct, if they can, in principle be separated by an agency with greater powers; and perhaps only God fits that description (or perhaps not, maybe there is room for an evil demon in the actual world).

The reason a proof of God is needed is rather that we need assurance that what we perceive 'clearly and distinctly' is true. Excellent point. I don't think however that the Cartesian Circle is sufficient to rebut this claim. There is a difficulty, to be sure. However, the Cartesian Circle is not a knock-down argument. And I don't think that an essay on the real distinction between mind and body should require you to defend your view on the Cartesian Circle. That would be a suitable topic for another essay.

I also liked your point about Descartes' claim that his essence as a mental substance is thinking, on the grounds that he cannot conceive of himself as not thinking. Why not run the very same argument substituting 'existing' for 'thinking'?!

It is relevant here to point out that Descartes himself raised the question, what exactly does happen to the soul when you are asleep? To my recollection, he doesn't have a definitive answer to this. The soul, as a unitary substance, cannot just go out of existence and come back again.

Your introduction of the idea of a 'third-person' perspective is crucial, because nowhere in the Meditations (or in any of his other writings, to my knowledge) does Descartes consider the sceptical hypothesis that there might be *nothing* besides myself, not even an evil demon giving me my experiences. There is something, which is my essence, which manifests itself as various modes of thinking (when I am awake) that also exists for the 'third-person perspective' of God, or an evil demon. This can be used to give sense to the idea that I still exist while I am asleep. The question of 'other minds' (hence, the 'third-person' perspective of materialism, cf. Nagel's criticism of this view in 'What is it Like to be a Bat?') doesn't come into it.

It is because Descartes never doubts the existence of an 'objective' view of the mind as essentially thinking substance that it is difficult or impossible to deploy Wittgenstein's argument against a private language, which (in my view, also Daniel Dennett's) is lethal against contemporary varieties of dualism that assume the existence of 'private objects' having a subjective side but no objective side. Something with the power of God (or an evil demon) could create me and 'my world' in the absence of a world of extended matter.

Berkeley was sufficiently impressed by that argument to conclude that idealism is the only coherent metaphysical theory. Because if 'what God has to do' to create me and my world includes creating other subjects of experience, and all the objects of our experience, then there simply is no extra task which consists in 'creating extended substance'. The job has already been done.

Whereas Descartes would say that in that case we *are* deceived. We think, talk and act 'as if' there is an external world (just as Kant argues we must in his 'Refutation of Idealism') but there is nothing 'out there' corresponding to our beliefs, just more of the same ('ideas').

If this is correct, then Descartes' real argument is with Berkeleian idealism, not with materialism. Arguably, the dualism this leads to is not a dualism of mind and body, but rather the Kantian dualism of phenomena and noumena. But that's another story.

All the best,



Statistics for Electronic Philosopher:

Total posts = 1008

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Original letters: June 2001 – December 2011

Posted: March 2011 – March 2014

© Geoffrey Klempner 2001–2014

Truth and knowledge, personal identity

To: Joao M.
From: Geoffrey Klempner
Subject: Truth and knowledge, personal identity
Date: 7th December 2011 13:05

Dear Joao,

Thank you for your email of 28 November, with your second essay for Possible World Machine, entitled 'Knowledge is not allowed', and your notes on unit 6, on personal identity.


Well, I was expecting this. I still don't see that any mileage can be got from 'removing the requirement of truth from the definition of knowledge', although you are not the first of my students to consider this.

Of course, I can tell you what David Cameron 'knows' in his heart (or bones) about the right way to pursue economic policy -- which is information that you can use to predict David Cameron's behaviour (oh, so predictable) -- without implying that he is in the right. On the contrary, he and his party are deeply self-deceived (I say), defenders to the bitter end of big business, the monied classes, privilege etc. etc.

This is one way in which we use the term, 'know' or 'knowledge', as it were in scare quotes. But it is not the primary way. Indeed, if it were not for the primary use of the concept of knowledge there wouldn't be a 'scare quotes' use.

In the primary sense of 'know', when I say that Joao 'knows' that P, I am committed to P, whatever P may be. If, as can always happen, I discover I was wrong about P, then, as a matter of logic, I have to withdraw my statement that Joao knows that P. I can still say that Joao believes that P, but I can no longer say that he 'knows' because one of the requirements for knowledge (in the primary non-Cameron sense) is truth. I was wrong about what I thought Joao 'knew'. Sorry!

But what is truth? Don't we have to define that? If you look at contemporary literature on truth, you will see that there as a growing consensus on 'minimalism' (a kind of revamped 'redundancy' theory), which acknowledges just the sorts of points you make against coherence, correspondence and pragmatic theories. You can't 'define' truth in terms of check boxes or criteria, because all the boxes can be checked and the proposition in question turns out to be false after all. (The suspect was innocent, despite all the massive evidence pointing to his guilt.)

My short contribution to the StudyPartners forum (under an alias) made the point that, from a minimalist perspective, the term 'true' is just a device for propositional quantification. Using this, we can set out the requirements for knowledge without even mentioning the term 'true'. Whatever P is, if I claim that A knows that P, then my claim is refuted if P is refuted. That's the whole deal with 'knowledge' and 'truth'.

Against the 'Queen's speech' idea, we arguably need a term like 'know' (as contrasted with 'believe', which doesn't carry the truth implication), because we are interested in identifying persons who have authority to give out information about a particular topic. You consult someone who 'knows', not someone who merely has lucky guesses. (That's the bare bones of my 'theory of knowledge' for what it's worth.)

Personal identity

I'm not much into reading literature, but Proust's 'Remembrance of Times Past' is standardly quoted as an example of a situation where one can say, 'I remember saying 'I love you', but I am not the person who made that vow to you.' This is a point about the criterion of psychological continuity. My capacity to access memories (such as 'my' vow) may be necessary, but it it is not sufficient for personal identity in the absence of an additional factor, which might be termed the 'act of self-identification'.

Consider the macho rugby player turned gay hairdresser. We can tell a story about a gay man who becomes a rugby player as a way of deflecting suspicion about his true leanings. Underneath, he was always the same. He still thinks fondly about the prop forward he had a crush on all those years ago. In this story, there is not only continuity of memory but also self-identification.

On the other hand, with very few adjustments to the story we can imagine the gay hairdresser resolutely refusing to identify with the rugby player. 'That wasn't me, it was another person.' The hairdresser still 'remembers' the rugby games, but as it were from a distanced, almost third-person perspective. They are not 'his' memories.

This is a variant of Butler's objection to the Lockean theory of personal identity, to the effect that Locke's psychological definition 'presupposes' identity rather than defining it. The memories in question must be *my* memories. But given that we are seeking a definition of 'me' or 'I' the requirement seems patently circular.

You can combine the psychological criterion with a requirement of physical continuity of 'something' (say, states of the brain) that is causally necessary and sufficient for memory. In this way we can distinguish between 'true' and 'false' memories (e.g. the lunatic who seems to recall things that only Napoleon could have known) or deflect the ridiculous claims of people who supposedly 'remember' their past lives under hypnosis.

The resulting theory still leaves open the possibility of amoeba-like splitting, and it also fails to deal with the self-identification problem (although this is a murky area, and potentially open to abuse -- e.g. the convicted mass murderer asking to be released on the grounds tha he is now a 'different person').

There's no definitive answer. You can save logic (e.g. in the case of iterated amoeba-like splitting) if you are prepared, e.g., to hang a hundred men for a single murder (because each of them 'is' the person who committed the crime). Primitive or not, our views are largely held in place by mere contingency, the brute fact that these science-fiction possibilities are not realized in the real world.

All the best,


Can you know that you are not dreaming?

To: Kristian D.
From: Geoffrey Klempner
Subject: Can you know that you are not dreaming?
Date: 1st December 2011

Dear Kristian,

Thank you for your email of 21 November, with your essay for the University of London BA Epistemology module, in response to the question, 'Can you know that you are not dreaming?

You have used the question as an opportunity to offer an exposition of Nozick's 'truth tracking' definition of knowledge and consequent denial of the claim that knowledge is closed under entailment. This takes up about two thirds of the essay. Then, as an added bonus, you suggest alternative ways of tackling the dream hypothesis: inductive/ probabilistic, coherentist and finally a return to the view which you explored in your last essay, according to which we can effectively bracket the dreaming question and just not worry about it, assessing knowledge claims in the normal way. This time, you have consider 'realist' and 'anti-realist' versions of the bracketing theory, both of which you find unsatisfactory. More on that later.

Although it's often said, I don't agree with what you say in paragraph two that Descartes' scepticism is the same as the 'brain in a vat' variety; at least, if we take it in the full-blown version, which Descartes leads up to in stages. If I am being given a perfectly coherent dream by an evil demon, then there is no such thing as space or matter; whereas if I am in a pod in the Matrix, all I am wrong about is how things are in the physical universe.

This difference is important, because in the 'Refutation of Idealism' in the 2nd edition of Kant's 'Critique of Pure Reason', Kant believed that he had offered an effective response to Descartes. If I know that I exist, then I must know facts about objects in an external world. (Later, of course, we realize that this is qualified by the doctrine of transcendental idealism -- space and matter are 'empirically real but transcendentally ideal'.) When Kant comes to consider the possibility that I might still be dreaming, i.e. just asleep, he dismisses this with a remark to the effect that this kind of question is one which we deal with in the same way as we deal with any other question about the best explanation of the course of our experience.

That reply effectively makes the same point as your argument from induction/ probability. Indeed, if we look at the matter this way, then it could be argued that there is nothing whatsoever special about the question, 'Can you know that you are not dreaming?'. It's just one of many varieties of inductive scepticism, along with, 'Can you know that a terrorist missile is not going to blow you up before you have finished writing your email?', 'Can you know that the person you thought was a human being is not an alien from a planet in the vicinity of Betelgeuse?'

-- I won't repeat what I said last time about the contextual issues raised for knowledge here.

I don't have any comment on your exposition of Nozick. You are probably aware that Nozick's theory has come under attack, not least for its failure to deal adequately with Gettier counter-examples, although various fixes can be attempted. I think that the idea of 'truth tracking' is important and worth saving. Indeed, it has become part of contemporary philosophical vocabulary, even among philosophers who don't buy Nozick's definition of knowledge.

Truth tracking does also seem to be the core intuition in the bracketing theory (sorry, I couldn't think of a better name -- the allusion is to Husserl, not altogether apposite). Even if my life is one long dream, the question of whether or not my beliefs track truth (or, rather, dream-truth) is a valid one to ask, and enough to keep us busy. But then one has to deal with the objections I raised last time about 'what it all means'.

However, I don't agree with you about the anti-realist construal, although I can see how you get there. This happens to be a topic which I spent much time on when I was writing my doctoral thesis. Michael Dummett was lecturing on mathematical intuitionism. John McDowell (my supervisor) had written a seminal paper criticizing Dummett's argument for an anti-realist theory of meaning, and linking him to Quine. My counter-argument was that the anti-realist has far more subtle resources, doesn't need to offer a revisionary theory of meaning, can keep the law of excluded middle, in fact doesn't need to 'say' anything other than to reject dialectically every attempt the realist makes to 'state' what realism 'means'.

Forget about the question whether the question whether I am dreaming 'has' an answer (realism) or 'doesn't have' an answer (anti-realism). One thing that both parties can agree on is the possibility that I will wake up (or seemingly wake up). That's the cash value of the hypothesis. The anti-realist isn't required to offer an 'anti-realist definition of truth'. An anti-realist (pace Dummett) can perfectly well accept that 'truth transcends verification' in the sense that you can never offer an adequate substitute for 'is true' in any terms that involve verifying, testing etc. (even the notion of the 'limit of inquiry', which will always be relative to the capacities of the inquirers). I might wake up, like Neo. Or I might be blown up in the next minute by a terrorist missile. (As it happens there's a prominent mosque opposite my office.) Or you might be an alien from Betelgeuse.

All the best,


Kuhn on the structure of scientific revolutions

To: Mark S.
From: Geoffrey Klempner
Subject: Kuhn on the structure of scientific revolutions
Date: 30th November 2011 12:36

Dear Mark,

Thank you for your email of 21 November, with your essay for the University of London BA Methodology module, in response to the question, ''Scientific theories are as often accepted on ideological as evidential grounds.' Discuss.'

You offer a clear and well-researched account of Kuhn's 'Structure of Scientific Revolutions'. Your decision to focus on Kuhn (rather than Feyerabend, or Kuhn and Feyerabend) looks to be wise, given the sufficient complexity of the issues raised by Kuhn.

On the one hand we have the description of 'normal science' and 'puzzle solving' vs 'scientific revolution', 'paradigm shift', with which (as you observe) many would agree, including traditionalists. It is common knowledge hat the history of science can be seen as a history of 'revolutions'.

On the other hand, there is the thesis of incommensurability, which on the face of it is outrageous. Of course, we can understand the phlogiston theory, the heliocentric theory, newtonian physics. There is nothing, or at least nothing relevant in these once widely accepted theories -- or 'world views' if one wants to be grand about it -- that we do not grasp or 'see'. If one were of a literary bent, one could write a novel about a physicist researching aspects of the phlogiston theory (in between attempts to transmute lead into gold).

Wittgenstein talks somewhere about the once widely held belief that rats are 'generated' by piles of dirty rags. I don't know whether any natural philosopher so-called seriously considered this, but if they did, the mind-set involved is not so strange or exotic that one cannot 'get into' it and understand it. The paramount importance of the authority of Aristotle in the Middle Ages, which seems so irrational to us now, is not 'incommensurate' with modern ways of thinking. On the contrary, we have the necessary tools as historians of science, to understand why consulting Aristotle could have been considered a far better research strategy than using one's own eyes.

What is 'ideology'? What species of ideology would allow a serious thinker to consider the possibility that dirty rags generate rats, or that everything that needs to be known in respect to the physical world can be found in the writings of some Ancient Greek philosopher who never performed a single experiment? More to the point, in what sense could *that* state of affairs -- seemingly absurd yet still 'understandable' one day apply to us -- from the perspective of future 'enlightened' observers to whom we appear no less ideologically illuded?

I want to agree with your conclusion. 'Individuals are complex creatures, and their decision-making depends on the roles they take... This individual complexity is compounded when they conjoin in groups, such as a scientific community, and group dynamics come into play.' There's much more to be said about this, however. The 'group dynamics' of the scientific community, or indeed the academic community at large, is not something that as an observer one finds always edifying.

The cause of truth fails to be served when decisions are made about research projects purely on the basis of the availability of grant funding (e.g. from corporations serving their own interests, not the interests of science), or when a noted authority makes pronouncements (e.g. Linus Pauling extolling the virtues of Vitamin C) which in the mouth of a lesser researcher would be dismissed as unverified conjecture, or just when following the desire to be 'in with the in crowd' brings far greater material rewards to the young researcher than going against the stream.

I have described ideological vices (the very term 'ideology' seems to me to connote a negative value) which 'we' can succumb to, but which one can also succeed in avoiding and rising above. In an 'open society' (Popper) these issues can be debated.

I would also question the dichotomy implied by the question between 'ideological' and 'evidential'. The traditional virtues will always be virtues, even when circumstances arise where we genuinely don't know what to do, e.g. where there is no way to give a 'value' to the probability of different alternatives, no obvious explanation why an experiment has gone wrong (e.g. Michelson-Morley).

It took an outsider like Einstein (was he a genius? I don't know) to consider the outrageous possibility that the speed of light really is constant irrespective of the motion of the source OR the observer. Einstein was practising the traditional virtues. He was responding the the evidence, just as the researcher is taught to do. The only difference is that, in a practical situation this can be more difficult than one would think, given the desire which we all have not to cast ourselves into the role of the fool.

All the best,


Thursday, March 13, 2014

Milesian theories of the primary substance

To: Alan H.
From: Geoffrey Klempner
Subject: Milesian theories of the primary substance
Date: 29th November 2011 13:32

Dear Alan,

Thank you for your first essay for the Ancient Philosophy program, in response to the question, ''Examining the theories of the Milesian philosophers concerning the nature of the primary substance, we find a progressive clarification of the questions asked and an improvement in the answers given to those question.' Discuss.'

As you observe, we have to labour under the great disadvantage of a paucity of evidence, so that there will be an inevitable degree of unverifiable supposition in the theories we attribute to Thales, Anaximander or Anaximenes. However, that said, the question makes a claim, or rather two claims, and the challenge is to see how, or whether, those claims can be substantiated in a way that, at the very least, can be seen as a plausible conjecture given the evidence we do have.

You also raise the question whether in fact the three Milesian philosophers discussed these questions with one another. It is plausible that they did, given the time scale, even if they were not strictly related as teachers to pupils.

Can we see a progressive clarification in the questions asked? Thales asks where all things 'come from' (or, more contentiously 'what they are made of' -- it's not clear that he made this distinction) and his answer is water, the stuff we drink. Thales also (a point you could have made) observed that 'all things are full of gods', a puzzling remark taken out of context but which could plausibly be seen as an answer to the question why anything happens at all, or why any object can act on any other.

How does Anaximander clarify the question where things come from, or the question what makes things happen? Arguably, positing the 'apeiron' as material which has no specific form of its own is his response to the question, 'Why water? why not some other stuff?' In response to the second, however, he offers the conjecture (which you could have mentioned) about the opposites 'paying penalty and retribution for their injustice according to the assessment of time'. The ultimate stuff of the universe is also the ultimate source of predictability and lawlikeness. That's a question which Thales doesn't seem to have reckoned with at all.

With Anaximenes, we have a further clarification of the question of change. We need a 'something' that changes but we also need an account of what this change consists in. As you note, his contribution is to posit the process of 'condensation and rarefaction' as the universal explanation for all substantial change. At one stroke this destroys the naive idea of 'opposites' as substantial entities existing in their own right. Everything is on a continuous scale, from hot to cold, from wet to dry, from heavy to light. On the other hand, Anaximenes doesn't seem to have anything special to say about the idea of lawlikeness. His air, like Anaximander's apeiron has mind-like properties, and perhaps this element of teleology was his way of acknowledging the fact that the universe is a 'cosmos' not a 'chaos'.

All three thinkers offer a cosmology, however, and that seems to be another valuable clue. This is the payoff, the thing that any 'physical thinker' is expected to supply, as a response to the traditional, more or less mythical creation stories. This is how the world is ordered, taken from the most general perspective, how it came to be; and one can justify that claim in terms of a theory about the very stuff of which it is made.

However, there is a problem with this account which commentators have raised. If, as I have suggested above, Anaximander was responding to the question, 'Why water?', then Anaximenes' rejection of the apeiron theory looks like a retrograde step. In discussing Thales, you say, 'Was [the claim that everything is water] to be taken literally as the substance of rivers, was he using the term metaphorically, or was he engaging in mythical speculation?' If, as seems plausible, he was offering a theory which rationalized views already current, such as the idea that water is of paramount importance in the scheme of things, then, yes, the claim was to be taken literally. If he did think that things are 'made of' water and not just that they 'come from' water, then when you look at water you are looking at the way things really are, the very bricks and mortar of existence.

Anaximander has an objection to this, a good objection. Yet Anaximenes seems to completely ignore this objection and revert to the kind of answer given by Thales. Modern readers tend to see Anaximander as the more progressive thinker, because he 'saw' the need for a more abstract principle, whereas in antiquity it was Anaximenes who was the more celebrated. So there is room for debate here.

All the best,


Justification of induction and Leibniz on free will

To: Alistair L.
From: Geoffrey Klempner
Subject: Justification of induction and Leibniz on free will
Date: 29th November 2011 12:38

Dear Alistair,

Thank you for your email of 19 October with your essay for the University of London BA Methodology module, in response to the question, 'What, if anything, can explain the rationality of reasoning according to inductive principles?', and your email of 25 November, with your essay for the Spinoza, Leibniz, Kant module, in response to the question, 'Can Leibniz sustain his claim that Caesar freely crossed the Rubicon?'

Once again, apologies for overlooking your Methodology essay. I have a system, which usually works very well, of printing off the email and also making an icon on my desktop with the student's name and date, at same the time when I email my acknowledgement.

I think what must have happened is that I overlooked the fact that I had two quite separate actions to perform -- record your payment and also queue your essay -- at the time when I sent my acknowledgement. Must do better next time.

Do please send a reminder if I take longer than two weeks to respond. My deadline is 10 days, and I usually succeed in replying within that time.

Rationality of inductive reasoning

This is a very thorough essay which most of the angles in the debate over the rationality of inductive reasoning. You wisely avoid the question of Popper's claim that the method of science is not inductivist but rather conjecture and refutation. Even if that were accepted, it remains true that in a myriad ways, we rely on inductive inferences all the time. Every purposive human action takes place against the background of an assumed predictability in the way the world (and our own body) works.

You also briefly mention Goodman's 'new riddle', although I found the idea that this involves the claim that 'induction cannot possibly be reliable' difficult to follow. If anything, Goodman's own 'solution' to the grue paradox -- the theory of 'entrenched' predicates -- looks like a route to the solution of the traditional problem of induction. The 'rationality' of certain basic practices consists wholly in the fact that 'this is what we do'. This is the bedrock, or the background against which significant departures from rationality are measured.

What is it to 'rely' on something, or some process? I rely on the fact that when I hit a key on my computer keyboard (the heavy classic Mac beige keyboard which I have fixed up to work with my G5) a certain pressure, and no more, is required to produce a character. My previous keyboard, after years of sterling service, developed a problem with some of the keys. Not knowing how hard you have to hit the keys means that you end up hitting them extra-hard each time. You could have fun running a Goodman-style argument for computer keys (which need to be hit with a force of 100 psi after time t) and imagining creatures who (by accident or design?) have evolved to anticipate this very event.

That we rely on a certain thing or process isn't a 'reason', in the sense of something you could use to persuade a doubter to put their reliance on that thing or process, if for any 'reason' they weren't prepared to. 'Come in the water's lovely.' 'It may be for you!'

But let's try to imagine someone who really would count as a 'practical sceptic' (not just the philosophical, armchair style) about induction. Say, someone who believes in 'Sod's Law'. According to Sod's Law, things we rely on are reliable, except at the precise time when failure has the worst possible consequences. Your hard drive will have a catastrophic breakdown just as you are in the process of transferring your precious work to a new computer. Your brakes will fail just as you are driving round the bend in the mountain pass.

A pragmatic argument could be constructed in favour of belief in Sod's Law, not exactly along the lines that -- as you show -- Reichenbach argues pragmatically in favour of induction, but still in the same ball park. It is pragmatically useful to rely on induction. But agents who believe in Sod's Law fare better in the long run because they take extra precautions. Admittedly, this isn't to disbelieve in induction, and therefore not an argument against the claim that if any method works, induction will work. But at least it gives the semblance of a genuine choice: should I be a simple inductivist, or would it be better to embrace inductivism modified by Sod's Law?

We are skirting on the edge of a grey area of human psychology, where issues such as self-fulfilling prophecy arise. Expecting things to go wrong can often be a cause of their going wrong. Not everyone is the same. We don't all put the same faith in induction. Why should there be an 'ideal' position to take? If not, what does that show about the 'rationality' of induction?

Hume, it should be noted, was perfectly satisfied with his 'human nature' account of inductive and causal reasoning. It isn't a paradox for him that there is no such thing as a 'rational justification', whereas the continued and distinct existence of objects ('On Scepticism With Regard to the Senses') is seen as paradoxical, requiring an extra 'fix' (the theory of fictions).

Leibniz on free will

You offer a good account of Leibniz's defence of free will, in terms of his theory of monads. I agree with you that, on the face of it, the defence doesn't look as if it would convince a sceptic. But what exactly is Leibniz setting out to do?

As you yourself admit, there are two things in Leibniz's theory -- the foreknowledge of an omniscient Deity and the principle of causality (for Leibniz, the Principle of Sufficient Reason as applied to the world of phenomena) -- which pose problems quite apart from any problems entailed specifically by the monad theory.

There is a problem raised for free will in the thought that at every moment God knows what I am going to do, and also a problem raised for free will in the thought that every action that I do is the causal result of the total state of the universe, including the state of my own body etc.

Given either of these things, there is no alternative possibility, e.g., to Caesar's crossing the Rubicon. God knew what Caesar was going to do, and it was impossible for Caesar not to cross the Rubicon given the state of the universe at the time when he pondered his decision.

The theory of monads is a metaphysical theory, an attempt to describe reality at the ultimate level. It's justification is, as you indicate, that alternative descriptions (such as the one offered by Descartes in his simple dualism of immaterial souls and physical stuff) are logically flawed. As in Berkeley's immaterialism, the phenomena are saved. Billiard balls continue to collide in predictable ways, the Earth continues in its orbit around the Sun. Wouldn't it be rather surprising if the thing or capacity which we rely on in our phenomenal existence -- our ability to reason from a practical perspective, make choices and act on them -- was undermined by the purely metaphysical description?

Like other philosophers (including Spinoza) Leibniz quickly dismisses the notion of 'freedom of indifference'. Leibniz's positive account of freedom, as you admit, in practice sounds very much like the standard analysis offered by compatibilism. My 'free' actions are those which issue from my own deliberative process, rather than things I do under external compulsion. All the distinctions we standardly make, the reasons for or against holding an agent 'responsible', can still be made with the theory of monads as the ultimate metaphysical background.

However, it could be argued that that point is at least not blindingly obvious. At first glance, the picture of you and I as 'windowless monads', pre-programmed to make all the decisions, undertake all the actions we will do in our entire lives looks the very picture of unfreedom. It's the 'freedom' of a clock to show 27 minutes past 12 one minute after showing 26 minutes past twelve.

Leibniz's task, as I would interpret it, is not to 'solve' the problem of causality or God's foreknowledge but simply to dispel this superficial reading of his own theory. As a bonus, he can argue that alternative metaphysical views make it more, rather than less difficult to draw the distinctions necessary to allow that, e.g., the things that God knows that I am going to do are my actions nonetheless.

All the best,


Milesian philosophy of physical explanation

To: Sean R.
From: Geoffrey Klempner
Subject: Milesian philosophy of physical explanation
Date: 23rd November 2011 11:48

Dear Sean,

Thank you for your email of 16 November, with your essay for the first three units of the Ancient Philosophy program, in response to the question, ''The possibility of a physical explanation of the nature of the world and how it came to be was a philosophical discovery.' -- how come?'

This is a very good essay which to a large extent succeeds in answering the question. You make good use of your study of Thales and Anaximander, and you also quote Russell in support of your argument.

I do sense a certain degree of strain in the way you have framed your argument, beginning with Russell's question, whether there is 'any knowledge in the world which is so certain that no reasonable man could doubt it', then admitting in your last paragraph that 'there may never be a knowledge of the world which no reasonable man could doubt', while upholding the value of 'philosophical doubt and inquiry'.

The question, as it stands, has a hint of paradox, and this partly accounts for the difficulty. Seeking a physical explanation of the nature of the world is physics, not philosophy. Physicists, or scientists generally, proceed by means of hypotheses which they not only test for internal consistency, but also compare with actual observation. A physical theory can be wrong, not because it commits any errors in logic, but simply because the question put to nature receives an answer which contradicts the answer that was expected.

Philosophy is the art of reason, and its results, such as they are, do not need to be corroborated by experience. A philosophical claim, if false, is false because of an error of reasoning or logic. (We do not always find the error.)

One of the things philosophers are interested in, however -- and it is one of the aspects of philosophy which most occupied Russell -- is the theory of knowledge or 'epistemology'. One of Russell's books is entitled, 'Human Knowledge, Its Scope and Limits'. You can reason about knowledge or its possibility, and such reasoning is itself not directly tested by experience, because it is presupposed whenever we test a theory against experience. In that book, as well as in his more accessible work 'Problems of Philosophy', Russell seeks to persuade the reader by means of reason. He is not putting forward a scientific theory.

At this point, one needs to insert a caveat, because one of the major themes in contemporary analytic philosophy has been the denial of an absolute divide between the methods of science and the methods of philosophy. The American philosopher W.V.O. Quine in his essay 'Epistemology Naturalized' asserted that 'there is no First Philosophy' (in the sense of Descartes' 'Meditations on First Philosophy'). Epistemology is a scientific inquiry, just like any other.

In other words, there is a debate here about the scope of philosophy: whether it is ultimately different from science, as Descartes thought, or whether it is in some sense continuous with science as Quine argues. In this topic, Russell is closer to Descartes than to Quine, even though his discoveries in the field of symbolic logic have played a major part in the development of Quine's views.

There is no hint of this debate in the work of the earliest philosophers, because the question simply hadn't arose. And yet it was not long before the split between physics and philosophy became apparent. You quote my claim that there are 'two thoughts' involved in the idea that the 'universe conforms to reason'. The first thought is that nature obeys laws, making it possible for us to put questions to nature and receive truthful replies (any false conclusions are the result of our ignorance or ineptitude). That's consistent with what the Milesians believed. The second thought, however, is that there are necessary truths about the world which can be discovered by reason alone. You don't need to consult experience, because there could not be a universe which did not conform to those truths.

An example would be the belief that the principle of causality is necessary and knowable a priori. That is something that the philosopher Kant tried to prove. This claim is not accepted today, at least by the majority of physicists. Einstein expressed his conviction that 'God does not play dice with the universe', but he did not attempt to prove this by means of reasoned argument. For him, it was a principle of scientific 'faith'.

At the time of the Presocratics, the split between physics and philosophy arose with the Eleatic school, Parmenides, Melissus and Zeno. Physics deals with mere appearance. Whereas reality, or what 'Is', is something totally different. That we live in a world of plurality, movement and change is a mere illusion.

Philosophy gave birth to physics. Yet the child of philosophy has now grown up and become independent, to the point where physicists such as Stephen Hawking openly challenge the continuing validity of philosophy as a discipline. See my answer to Alan (who is actually, on of my Pathways students taking Ancient Philosophy!) at

All the best,


Donald Davidson on radical interpretation

To: Christian M.
From: Geoffrey Klempner
Subject: Donald Davidson on radical interpretation
Date: 22nd November 2011 12:38

Dear Christian,

Thank you for your email of 13 November, with your essay for the University of London BA Philosophy of Language module, in response to the question, 'What role does the radical interpreter play in Davidson's account of meaning?'

This is a question which begs for an account of what it is to offer a 'theory of meaning' (cf. Dummett 'What is a Theory of Meaning? (I)' in Guttenplan 'Mind and Language', 1975, and 'What is a Theory of Meaning? (II)' in Evans and McDowell 'Theories of Meaning', 1976). Between Dummett and Davidson, to take just two philosophers who have been involved in this debate, there is a huge gulf concerning the appropriate aims of a theory of meaning. What is it to represent a speaker's knowledge in the form of an explicit theory (if that is the right way to put the question)?

Considerations about rule following, which you refer to at the end of your essay, are very much at the forefront of Dummett's argument (especially in WTM II) regarding the requirement that knowledge of meaning be 'manifested' in linguistic practice. (See also McDowell's seminal article, 'Truth Conditions, Bivalence and Verificationism' in Evans & McDowell, op. cit.)

Davidson's original idea is beautifully simple, and it is not so hard to see how he could have inspired an entire generation of graduate philosophy students (as it happens, the generation just before me) to follow the example set by 'On Saying That' in seeking to tame 'difficult' semantic idioms in a Tarski-style compositional analysis. That's an aim worth pursuing in itself, for the illumination it provides, quite apart from the question which Davidson pursued into the nature of radical interpretation.

However, I do accept the point you make here, that radical interpretation looks like, or is presented in a way which seems to fill a lacuna in Davidson's original account in 'Truth and Meaning'.

There is a subtle point to be made here (exploited my McDowell) concerning just who we imagine to be doing the 'radical interpreting'. An alien from the planet Zog, or just you and me? Just as Davidson's Tarski-style analysis shows meanings rather than offering a reductive analysis (because it's compositionality that we're after, nothing else) so the work of the radical interpreter in 'making sense' assumes a great deal (a point you effectively make, but in a way that looks like a criticism of Davidson) about our common nature and culture.

It is something quite different to seek the kind of reductive, behaviouristic account of meaning of the sort which Quine is interested in. Quine (along with Dummett) is McDowell's main target in 'Truth Conditions, Bivalence and Verificationism'.

There's a good, sophisticated account of the kind of 'holistic' theory Davidson is seeking in Christopher Peacocke's 'Holistic Explanation', 1980. There is a circle, as you describe, of beliefs, intentions and meanings which offers no single point where one can 'break in'. The idea that one starts with sentences that 'the natives' would readily assent to (like the sentence 'Snow is white' in the presence of snow) is sadly deficient if taken literally as a recipe for radical translation, indeed misses the point about holism, that there are no privileged entry points. We just make assumptions and test them, then form new assumptions in the light of those results and test those, and so on, a process which in principle can carry on indefinitely.

Why is this interesting? why focus on radical interpretation when in the real world we rarely find ourselves in a position of needing to slow down in this way?

From a broad perspective, what Davidson is seeking is an account of 'meaning as use', just as Wittgenstein sought. (What's so interesting about the debate is that Dummett thinks he is doing this too!) It is in human behaviour, including linguistic behaviour, that the facts about meaning are to be found, and the superstructure of semantic interpretation rests loosely on the hard, nitty gritty facts of bodies and vocal chords in motion.

So the question really comes down to: is Davidson's story of the radical interpreter the best way to approach this? As you observe, Davidson adjusted his theory as time went on. But the key point, it seems to me, is to comprehend this 'looseness of fit', a point which Wittgenstein also effectively makes in his considerations regarding rule following.

If we can't adopt the original suggested methodology of 'identifying T-sentences' (like 'snow is white' in the presence of snow), what is left of the suggestion that 'there is' an appropriate procedure for the radical interpreter? What is to be gained from even raising methodological questions at this point? This is where I am sceptical.

So I am tempted to say that Davidson is relying here on a perceived connection between his original account in 'Truth and Meaning' and considerations on radical interpretation, which just does not exist in reality.

Grade: 70

All the best,


Wednesday, March 5, 2014

Plato's proofs of the existence of a soul in the Phaedo

To: Max W.
From: Geoffrey Klempner
Subject: Plato's proofs of the existence of a soul in the Phaedo
Date: 22nd November 2011 11:37

Dear Max,

Thank you for your email of 14 November, with your essay for the University of London Plato and the Presocratics module, in response to the question, 'Discuss whichever you take to be the most convincing argument for the immortality of the soul that Plato offers in the Phaedo.'

This is an interesting and original take on Plato's discussion of the soul in the Phaedo, which I have a lot of sympathy with. What Plato is offering here is a series of considerations, none of which appears conclusive or is intended to be, which as a whole give support to the theory of the soul, as a theory, that is to say, an 'inference to the best explanation' (Peter Lipton) as a contemporary philosopher would describe it .

Although inference to the best explanation is usually presented as what scientists do, it has become increasingly fashionable amongst analytic philosophers to talk about offering 'theories' rather than 'analyses'. Along with this shift -- which I have witnessed over the last 30+ years since I did my BA -- goes an increasing scepticism about the 'a priori' nature of philosophical claims, commensurate with Quine's attack on analysis in 'Two Dogmas of Empiricism' and his insistence that 'there is no First Philosophy'.

To take a pertinent example, the view that the mind should be seen as a sophisticated computer or Turing Machine (Daniel Dennett 'Consciousness Explained') is a partly empirical claim, based on our best (still very limited) knowledge of the way the brain works. Connectionism (the view that there is no 'program' for the human brain that could be written in 1s and 0s) is a competing claim. Plato would have revelled in this debate. Indeed, it seems to me that the Pythagorean claim that the soul is an 'attunement' is remarkably close to Dennett's speculation in 'Consciousness Explained' that 'downloading' the program of your brain onto disk and then 'uploading' it into a fresh body is the best chance for human immortality!

You probably don't need me to say that an answer such as the one you have given would not greatly please an examiner. If you really think that Plato's first argument is the most convincing, then you should concentrate on it (you don't need to give your reasons why you prefer it, the question doesn't ask for this) and articulate the argument in detail, supplying missing but necessary steps as and where needed.

I am prepared to accept, for the sake of argument, that despite the scholarly consensus the first argument is the most convincing, when fully laid out. I take your point that we are choosing between arguments none of which convinces or is intended to convince on its own. That would be a valid point to make, in the spirit of 'questioning the question'. Still, if the first argument has any value, then it should be possible to state it in a way that enables other students to appreciate that value.

If we consider the role of 'opposites' in Greek philosophy from the earliest Presocratic philosophers, one thing that emerges is a growing resistance to the idea that opposites exist, per se, as 'opposites'. Whereas Anaximander has the opposites transmuting into one another under the guidance of a lawlike force, in Anaximenes there is no such thing as 'the cold' or 'the hot' as such, merely relative differences in compression, a view consonant with modern physics. The point is made even more strongly in Heraclitus.

The picture we gain, which Plato helped himself liberally to, is a universe awash with energy, where nothing is truly dead, for all time; the soul itself is a component part of, or shares its essence with the principle (the Logos) which animates the universe, an idea which later came to be incorporated in Plato's eternal Forms.

In other words, the strength of the argument is not so much, as you seem to present it, that it anticipates contemporary science (DNA etc.) but rather that it summarizes and presents an entire tradition of philosophizing (ignoring the atomists) where the universe is soaked with 'mind', where teleology rules, and where the part we as human beings play is far more than just the part played by our perishable material bodies. The mind transcends physical existence. It is what connects us, in the literal sense, to the universe.

How to encapsulate this in an argument? Take the statement, 'If opposites did not always correspond with opposites...'. What the examiner would really like to see here is a series of numbered steps, 1, 2, 3 etc. where the claims are clearly laid out and the inferences tested. A good way to do this is to first present the argument as Plato presents it, close to the text. Then look for loopholes. Which steps fail to convince? What extra premisses, or steps, are needed to make the argument appear stronger? Use all the latitude you need. It is not at all implausible to claim that Plato is assuming knowledge of a tradition, so make use of this background information in shaping and honing the argument.

Then, and only then, you can state why you still find that the argument fails fully to convince. Nevertheless, you would have made a case that deserves to be reckoned with, for your claim that you find the argument the 'most convincing'.

All the best,


Aristotle's case for a prime mover

To: Scott B.
From: Geoffrey Klempner
Subject: Aristotle's case for a prime mover
Date: 21st November 2011 12:03

Dear Scott,

Thank you for your email of 10 November, with your essay for the University of London BA module on Aristotle, in response to the question, 'In what manner is Aristotle's god explanatory?'

This question can be taken in two senses: in what manner did Aristotle intend his conception of god to be explanatory? and does he in fact succeed in that intention?

It needs to be said that Aristotle does not set out his argument for a prime mover in such terms. According to the argument he lays out, the existence of a prime mover is necessary (as you observe, in order to account for the fact of 'motion'), and that is why we should believe it. The extent to which it 'explains' anything is arguably an additional question. One possibility which is not ruled out from the start is that the existence of a prime mover is necessary, as a matter of logic, but the conception of a prime mover does not 'explain' anything (in any sense in which we would understand the notion of explanation), and is not intended to.

Finally, there is the question, which you do raise, whether the theory as presented by Aristotle holds together, whether it is in fact internally consistent. As you note, with regard to Aristotle's 'stellar intelligences' moved to action teleologically by their contemplation of the prime mover, 'Something that is both immaterial and has potentiality does not fit easily into Aristotle's scheme of things.' This point would have been worth elaborating on.

According to you, the short answer to the exam question is that Aristotle's god is intended to be explanatory by being the final cause of motion rather than an efficient cause. However, there is a problem with the way you lay the argument out, contrasting the Aristotelian prime mover with the 'first cause' of the cosmological argument.

A potted version of the cosmological argument -- which is effectively the version you give -- would be that the chain of causes and effects cannot go back indefinitely. There must be a first event, the first cause, which acts as the beginning of the chain. This picture fits the story of Genesis, but it is limited because it assumes from the start that the universe must have a beginning in time. It is not, however, necessary to assume this.

The god of Judeo-Christian theology is not an entity which exists in time. god views the universe 'sub specie aeternitatis', under the aspect of eternity. He stands outside the causal series. It is perfectly possible, therefore, that the causal series stretches back indefinitely ('to infinity') while god is the ultimate, timeless, cause or creator of the entire series. Why would you still need a 'first cause' in this sense, if we allow that there is no first event in time? An analogy which is sometimes given would be that of a object, say a glass chandelier, suspended on a long chain. Each link in the chain is held in place by the link above it. Let's say the links are indestructible, capable of bearing any weight. If you asked what was holding the chandelier up, would it be any answer to say, 'There is no first link, because the chain stretches upwards to infinity'? Clearly not.

Later, in your essay, you do note that an explanation is needed for the continued existence of the universe at any given moment in time. This was in fact a view which Descartes argued for, and which Spinoza took to show that the only thing that can be genuinely regarded as a 'substance', as not depending on anything else for its continued existence, is god. Ordinary objects have no magical existential inertia. The very fact that an object exists, at any given moment, requires a sufficient explanation, which is not provided merely by the fact that it existed at some previous moment.

Armed with this conception, the defender of the cosmological argument can happily ignore the question whether or not the universe has a beginning in time. Either way, it's existence now depends on god's creative action.

However, this picture, of god the ultimate creator of the infinite series of events stands in stark contrast with Aristotle's prime mover which, as you say, has no knowledge of the imperfect, empirical world. It follows that the existence of a prime mover cannot explain *everything*, in the way that the Judeo-Christian god does. Consequently, there is no 'problem of evil' for Aristotle.

So what we have is an ultimate teleological explanation, rather than a causal explanation. But this teleological explanation is limited by the fact that it does not apparently connect with the things of this world -- the kinds of teleological questions that arise when we consider the form of a horse or a tree, or a man.

Why should the universe continue in existence? At the end of your essay you offer the suggestion that a 'slight shift in the meaning of the word 'creator'' might lead us to regard Aristotle's prime mover as accounting for the material universe continuing to exist from one moment to the next. This is in fact the Cartesian (and Judeo-Christian) view outlined above. But can we attribute the idea to Aristotle?

As a matter of brute fact, there is motion, and to account for this Aristotle argues for a necessary cause of motion. Given such a necessary cause, there *must* continue to be motion. The material universe cannot cease to exist, otherwise motion would cease to exist, contradicting the argument for a prime mover. But this does not make the prime mover a 'creator' in any sense that we would recognize. The prime mover accounts for the fact that the universe exists, leaving open the question *how* it exists.

All the best,


Knowledge and belief in Plato's Republic

To: Emelie G.
From: Geoffrey Klempner
Subject: Knowledge and belief in Plato's Republic
Date: 17th November 2011 12:42

Dear Emelie,

Thank you for your email of 9 November, with your essay for the University of London BA Plato and the Presocratics module, in response to the question, 'Explain Socrates' argument about knowledge and opinion at the end of Book V of the Republic. Does it work?'

This is a well thought out and carefully written essay, which does not baulk at the difficulties in interpreting Plato's text.

I have to say at the start that I am very strongly tempted to agree with Plato about the objects of episteme and doxa. His argument has nothing to do with scepticism as this is now discussed, and I'm pleased to see that you don't fall into the error of confusing Plato's qualms concerning empirical judgement with doubt of the Cartesian variety. The objects of doxa 'are' and 'are not'. They are F when taken in one way or from one aspect, and not-F when taken from another.

Consistently with this view, we should not agree that a 'finger is a finger', no matter what, and I don't think Plato could possibly think this. On the contrary, as with any other biological feature, there will be cases where we are clear that something is a finger, or not a finger, but also cases in between where we are not sure what to say. Of the form of 'Finger' there is no doubt. The problem is applying that knowledge to a particular case.

The one exception to this rule -- the pervasiveness of vagueness and relativity in empirical judgements -- are quantitative judgements. 'How many fingers am I holding up?' Assuming we have agreed from the start that these are fingers, not amputated stumps or prosthetic fingers, the act of counting is not relative, or vague, but always precise. This is the one case where features of the world of the super-sensible are precisely instantiated in the sensible world.

What is so wrong with this view? You raise a difficulty (Problem 1). There are two aspects to this:

First, it seems impossible that one can ever know that a man, or a city is 'just', because these objects like everything else in the sensible world are subject to different views or perspectives, and also vagueness. No man or city is perfectly just, in every respect. Only the form of justice is perfectly just (leaving aside the question whether Plato needs self-predication in this strong sense to make his point). In which case it is hard to see how this great faculty exercised by philosophers -- the faculty of episteme -- can be of any practical use.

Secondly, Plato explicitly says, in the Meno, that you can gain knowledge by 'tying down' belief. There is every difference between having a belief about the right way to Larissa and knowing the way. In other words, he seems explicitly to accept in the Meno that there are cases of knowledge in the sensible world, flatly contradicting his view in the Republic.

I don't see these as serious difficulties, however.

Judging whether a man, or a city is 'just' can never be a final, all-or-nothing matter. The most just man has his foibles or vices. Moreover, this judgement is always open to revision in the light of further experience, or in the light of further comparisons (finding a man who is 'even more' just than the man you thought was 'perfectly' just). It's an open-ended quest, to determine how and to what extent justice is realized in this world. However, you are not even going to get started if you don't know what justice is. That's why only the philosopher is qualified to debate such matters. The empirical conclusions of the philosopher are doxa, not episteme, but they are still miles ahead of the judgements of non-philosophers. In the world of doxa, not every judgement has the same value or credibility.

In the Meno, Plato is clearly using an analogy. He is not saying that anyone, ever, can have episteme of the Road to Larissa. The point is rather about the difference between a theory or all-things-considered judgement based on various more or less persuasive considerations, such as one might have from asking friends, consulting maps, looking up Google etc., and the kind of competence and direct experience demonstrated by someone who travels the road every day and knows it 'like the back of one's hand'. Practice, and repetition, convert mere doxa into something much more like episteme, even though it isn't strictly episteme.

The intended analogy here is with the kind of progression one makes when one engages in the Socratic dialectic with a term like 'virtue', until one becomes fully proficient at it. When you are fully proficient, then you 'see' the form of Virtue: you have episteme. (It is another question whether Socrates or Plato believed that anyone, including themselves, had ever truly achieved this.)

One of the reasons why the Republic has traditionally been one of the favourite entries on 'introduction to philosophy' book lists is that Plato's argument is ultimately about the defence of philosophy as such, as a practice and a discipline. The world is full of 'experts', all of them merely 'lovers of sights and sounds' who have never once imagined or guessed that there can be anything else, any other form of inquiry than inquiry into 'things'. Of concepts as concepts, or the idea of a priori judgement, they are completely ignorant.

One should not make the mistake of tying Plato's view about doxa and episteme to the two-world theory, at least in the full blooded sense in which Plato held it (of course, we don't know for sure what Socrates' views were). To recognize that philosophy has a distinct subject matter, in the way that Plato emphasized this, does not commit one to any particular metaphysical theory.

All the best,


David Lewis, equivalent worlds and knowledge

To: Kristian D.
From: Geoffrey Klempner
Subject: David Lewis, equivalent worlds and knowledge
Date: 16th November 2011 11:31

Dear Kristian,

Thank you for your email of 8 November, with your original essay, 'Equivalent Worlds and Knowledge' for the University of London BA Epistemology module.

You've really thrown down the gauntlet with this effort, which leaves me in no doubt that you are capable of gaining a 1st class honours degree. However, I think that you will need to temper your enthusiasm with a dose of common sense. It is rather easy to be carried away by the beauty of an idea or a theory, to the extent that one loses ones grip on plain old boring reality :-)

First off: the wild 'metaphysical' cases such as Russell's five minute world (commemorated at -- the image is the grave of my mother's first husband who died in WWII, assuming that the universe is older than 5 minutes) or brains in vats etc. are not the only challenge to the closure principle. It's much easier than you seem to credit to question closure, as David Lewis in his contextual account of knowledge has amply demonstrated.

In my Answer to Demetreus I offer the following example:
'Is Bob cheating on Sue?' 'Yes, I saw him together with Mary.' 'Does Bob have a twin brother in Australia?' 'Search me if I know.' 'If Bob had a twin brother, wouldn't it be possible that it was his twin brother on a visit from Australia you saw with Mary?' 'Yes, I suppose so.' 'In that case, would you like to revise your statement?'
All it takes is a question. The question doesn't have to be, 'How do you know you haven't eaten 14 Pound. of hallucinogenic salmon?', or 'How do you know you're not a brain in a vat?'

OK, let's just look at the metaphysical cases and forget closure. I can see why you're tempted by the idea that when I say, e.g., 'Max Mann died in WWII', that is kind-of true even if the world is only 5 minutes old. I can visit the grave. There are dusty documents stored somewhere in an archive. Everything I will ever experience in regard to the question of the unfortunate death of Max Mann will be just as it is regardless of whether a mischievous demon is playing tricks on us or not.

There's actually a similar -- and really metaphysical -- point to be made here regarding theories which are truly non-empirical (as this is not, as you concede, since the mischievous demon knows the truth). Berkeley in his theory of immaterialism claimed to be defending common sense, which seems crazy but in a Berkeleian world everything is as you would expect it to be from an empirical standpoint, and all that's missing is Cartesian doubt about an 'external world'.

In between the truly metaphysical case, where arguably knowledge claims are unaffected (I know there's a tree in the quad even if 'the tree the quad' is just an idea in God's mind) and the example of Bob, Sue and Mary, there are various levels of generality, in some of which, depending on the reach of our powers of investigation, the truth will never be known. However, even if we take your quasi-metaphysical cases, I don't think that it is true that we just don't care about the 'real' truth (as opposed to the experiential 'truth').

Let's say that there's a clever conspiracy which I will never know anything about (because it's so secret and clever) to mock me and make fun of me behind my back, while all the people I meet face to face or communicate with by email show me the greatest respect. I glow in the admiration of my students and peers, while in reality I am despised. Or let's say I live my entire life believing that my wife adores me when in reality she has enjoyed an long-running affair with my best friend and only married me for my money.

I don't want the experience of being respected and admired, or the experience of being loved. I want the real thing. The fact that the example has been set up in such a way that I will never discover the truth does not alter that fact. As Aristotle would claim, I am not a 'happy' man even though I sincerely believe myself to be happy. The test is how I would think if I did happen to stumble upon the truth.

It occurs to me that a generous interpretation of your view of knowledge might put it quite close to Lewis's view, and also to the kinds of claims that the pragmatists (such as James) made about truth. I'm not ruling out entirely that there could be a useful theory here about the precise 'meaning' of knowledge claims, how some claims to knowledge are very much like tools which we use to deal with the world, while others have layers of added 'meaning'.

The question that is really calling out to be answered here is why we have a term for 'knowledge'. Maybe there would be sufficient justification to coin hybrid semi-factive propositional attitudes with built in elasticity to cope with the kinds of cases which you describe. Then I could say, with perfect accuracy, say, that I Gnow that Max Mann died in WWII regardless of whether an evil demon is playing tricks on me or not.

All the best,


Friday, February 28, 2014

Karl Popper's response to Hume

To: Mark S.
From: Geoffrey Klempner
Subject: Karl Popper's response to Hume
Date: 15th November 2011 12:38

Dear Mark,

Thank you for your email of 6 November, with your essay for the University of London BA Methodology module, in response to the question, 'Does Popper provide an adequate response to Hume's problem of induction?'

You have taken this question as an invitation to discuss the merits of Popper's account of falsifiability as a descriptive and normative account of scientific practice.

As you have covered many of the main lines of criticism and defence, I was surprised you didn't mention the difficulty posed by existential statements, such as, 'There is an uncharged subatomic particle which has exactly one half the mass of a neutron' (I don't know whether this is true or not -- sounds false to me). This looks like a statement you could verify, at least by the standards of particle collision data (whose interpretation is of course heavily theory dependent) but it cannot be falsified.

Well, so what. A physicist wouldn't say this unless they had a theory which predicted it. A theory which only has positive existential claims like 'somewhere in the universe there is an uncharged particle with half the mass of a neutron' as its logical consequences is not scientific by Popper's criterion.

At one point in your essay you note that Popper is not seeking to show that induction is rationally justified. Of course not. His response is that the attempt to seek a rational justification for induction is just a wild goose chase.

However, the problem with this easy answer, which arguably should have been a focus of your essay, is that Hume makes precisely this claim. The 'problem' of induction for Hume is not something which he treats in the same way as the seemingly paradoxical conclusion (in 'On Scepticism With Regard to the Senses') that we cannot make sense of the assertion that objects which we do not perceive have a 'continued' and 'distinct' existence. (The only solution is to give up philosophy and take a rest from these 'strained speculations'.)

For Hume, the process of induction describes how beliefs are in fact formed. Moreover, there are 'rules for judging causes and effects', which themselves have arisen from the same source (habit), which allow us to 'reason' about alternative theories and decide which is 'best'. The point being that there is no standpoint or foundation from which we could judge the rationality of induction, or science, as a whole. It's just what we do.

Popper is right (in my view) to respond that Hume's account is to a considerable extent infected with the 'Baconian myth', but then Hume's interest was different. His 'rules' are elementary, hardly a philosophy of science or a methodology. You can read Popper as pointing out that there is something really interesting here, about how far actual scientific practice deviates from the mythical inductivist picture. With a bit of added hyperbole, maybe.

You are right to emphasize that the key question is why we rely on the results of science. But not all science, of course. There are the games cosmologists or particle physicists play, which seem to have little significance for the 'real' world. Not a lot different, in fact, from the games scholars of the Presocratics play, arguing the toss over different interpretations of Heraclitus. (Imagine you are a bemused bystander who in a misguided attempt to end the argument tries to formulate a 'philosophy of Presocratic interpretation'.)

However, at the back of the practical application of science lies our absolute, unremitting faith in the uniformity of nature. When you put questions to nature the answer will always be the truth, the whole truth and nothing but. It's up to us to put the right questions -- so often we fail to do this, or else lamely misinterpret the answers that nature gives. I don't see any merit at all in attempting to justify this faith or demonstrate its 'rationality' and neither did Hume.

If you asked Popper, what would he say? Is 'nature always tells the truth' also a falsifiable hypothesis, on the same level as all the rest? It's something we hold on faith, a presupposition of scientific inquiry. It seems to me perfectly acceptable to say that you don't judge the ultimate presuppositions of science by the standards of science. What an absurd idea!

Nitpicking objections apart, the great strength of Popper's vision lies in his realization that when we do science, there are always several theories 'on the table', some of which we like a lot, others which we don't like nearly so much but can't rule out. There are no logical or methodological rules for 'liking'. A lot depends on fashion, grant funding, etc. Which is not to say that anarchy rules, on the contrary (I've made his point before).

However, you don't build bridges on the basis of your favourite theory. That would be a rather silly thing to do. When it comes to bridges something else comes into play. What exactly is this? What response could Popper offer here other than the Humean response, which he apparently rejects? But does he, really?

To offer a 'conjecture and refutation' model for science (and maybe for Presocratic interpretation too -- see Popper's 'Back to the Presocratics') is not to claim that all human beliefs follow this pattern. If the presuppositions of science are not science, then neither are the basic beliefs which guide our everyday actions, Humean style, habits which we would never once think of questioning. This isn't necessarily an answer, or an adequate defence of Popper. He owes us an account of what it means to be a 'rational agent' at the basic, nitty gritty level. Corroboration looks like such an account. All Popper needs to do is swallow his pride and acknowledge his indebtedness to Hume.

All the best,


Are possible worlds really 'real'?

To: Bernd K.
From: Geoffrey Klempner
Subject: Are possible worlds really 'real'?
Date: 15th November 2011 13:21

Dear Bernd,

Thank you for your email of 7 November, with your first essay for Possible World Machine, in response to the question, 'Are possible worlds really 'real'?'

It's fair to say that you don't really answer this question, although you initially go about this in the right way. If you hadn't stopped when you exhausted the 800 word limit (which is in fact generously elastic, I should have told you, sorry!) I don't think from what you have indicated that you would have got there.

Just one point: it was Berkeley, not Descartes, who denied the existence of a material world of objects in space. Descartes raises the question of scepticism about an external world then answers his own question by means of the God hypothesis and the theory of mind-body dualism.

You are right that there is (at least in the current scientific climate) a strong disposition towards regarding questions about 'reality' as being measured by the standards of physical existence, dualism notwithstanding. However, what is interesting about the question whether possible worlds are 'really real' is that a materialist can happily debate this with a Cartesian dualist, neither having to give ground on their fundamental metaphysical theory. (Or with a Berkeleian idealist, for that matter.)

The key point, which you do raise, concerns relation to time. Even the 'worlds' generated in the many-world theory of QM trace back in a tree-like structure to specific points in time (e.g. an electron either does or does not fall into a lower orbit releasing a photon). Whereas, according to David Lewis, the chief proponent of the 'really real' theory of possible worlds (in his books 'Counterfactuals' and 'On the Plurality of Worlds') possible worlds each exist entirely in their own space and time with no point of contact with the actual world.

It makes to sense to ask the question 'when' the possible world where GK decided to take the day off today 'occurred'. It is not as if somewhere, right now, a counterpart of GK is enjoying a late, lazy breakfast. This is something I might have done, despite the pile of work on my desk, but wisely didn't do.

In the 'larger world of memories and imagination' (your last sentence) worlds exist, but these are just imagined, made up, constructed. If this is how we should understand the ontology of possible worlds, then that is tantamount to saying that possible worlds are not really real. They are not real at all. They exist only in the imagination.

Now one can debate whether, e.g. unicorns or Santa Claus exist 'only' in the imagination, or whether they have a more solid, cultural basis. There's all the difference in the world between one person's overheated imagination, and the shared memories/ imaginings of a significant portion of the human race. But still they are not 'real'. A unicorn, it is said, can detect whether a woman is a virgin or not. You don't need to undertake a scientific test for this, because this is true simply by virtue of myth and fable.

David Lewis is not being fanciful when he asserts that possible worlds are not like unicorns or Santa Claus (although there are possible worlds where 'unicorns' or 'Santa Claus' do actually exist). The existence of possible worlds follows as a logical/ metaphysical principle, if you accept a plausible view about the nature of language, viz. that the meaning of a statement is given by its truth conditions (a view first formulated by the great German mathematician Gottlob Frege).

It is the argument which is put into the mouth of Dr Phillips' student Brenda, in unit 1: 'What we can or cannot imagine, or what we think about possible worlds, is not what makes those worlds real. Because we can be wrong. Our thoughts about possible worlds are true or false depending on something -- whatever it is -- that is somehow independent of those thoughts. What makes possible worlds real, in other words, can't simply be our thinking about them. Our minds discover something that has a reality independent of our minds.'

When I assert, 'There is a mug of lukewarm coffee on my desk,' my statement has truth conditions, it is true if the facts are a particular way, and false if the facts are a different way. I'm telling you that it is true (you have to believe me). It is made true by the thing on my desk which is, in fact, a mug of lukewarm coffee.

When I assert, 'If I had taken the day off today I would have enjoyed a lazy late breakfast', my statement according to David Lewis also has truth conditions. But what could these be? What makes it true, if it is true, that I would have had a late breakfast rather than setting off at the crack of dawn with my camera? Lewis's answer: The similarity of possible worlds makes it true. In the 'nearest', most 'similar' possible worlds to the actual world, I enjoy a lazy breakfast. That's a fact, just like the fact about the mug of coffee. If it is a fact, then possible worlds must be 'really real'.

How good is that argument? Where's the loophole? Surely, we don't want to be lumbered with this massive metaphysical extravagance! Or is it? What would Occam say? But then he would owe us an alternative, workable account of the semantics for counterfactual conditionals.

All the best,


Can truth be defined?

To: Kyriakos C.
From: Geoffrey Klempner
Subject: Can truth be defined?
Date: 9th November 2011 13:04

Dear Kyriakos,

Thank you for your email of 31 October, with your third essay for Possible World Machine in response to the question, 'Can truth be defined? If you think it can, give a definition and explain its philosophical significance. If you think that it cannot, what considerations should the philosopher draw from that?'

Heidegger makes much of the point that for the Greeks truth was 'aletheia', that which is 'unconcealed', brought into the light of day (I understand that 'lethe' can refer to forgetting or concealing). What does this imply? You make the point that for the Greeks, the actual word for 'truth' can be deciphered as a complex thought. It is not just a label.

One could say that 'truth is that which is unconcealed' is intended as a definition of truth. Something that shows itself, that remains in the open, which we will not permit to be lost (forgotten). Yet this already poses a problem. Because facts, as such, are never just 'in the open'. We investigate the world, sometimes with great patience and persistence, and an answer comes to our questions (the scientist 'puts questions to nature'). But this answer is an interpretation, a deduction or induction, a conclusion. It is not just 'something seen'. It is almost as if the Greeks defined their 'truth' or 'aletheia' in a way which makes the acquisition of truth well nigh impossible. All our patient striving merely takes us from A to B, and from B to C. We never get to the truth, as such.

Yet Parmenides, repeating the words of the Goddess, asks us to believe that he has attained the 'well-rounded truth', 'It is', is all one needs to say. The truth, the whole truth, is all that follows from this proposition, and everything else is illusion.

But why can't 'true' be a useful label? Let the Greeks have their 'aletheia' and let's just concentrate on whether the word we use, in everyday discourse, has a definition. You are the second student whose work I have responded to today. That's true. Adding the label 'true' doesn't add any information. If you didn't believe me in the first place then assuring you that what I say is true wouldn't convince you either. But maybe there are circumstances where the use of the label 'true' is useful and necessary.

Wittgenstein in the 'Philosophical Investigations' argues that 'agreement in judgements' is the necessary condition for the very existence of meaningful discourse (contradicting the principle he held in the 'Tractatus' that we cannot allow that 'whether a proposition has meaning depends on whether another proposition is true'). If truth depends on, or is defined in terms of 'agreement', how can one leave open (as one surely must) the possibility, however seemingly remote, that we are all wrong? 'Our' world is flat, say. That's the truth, so far as we are concerned.

I would regard this as a fatal problem if one were seeking to define truth in terms of agreement. However, I see no contradiction in asserting (in Kantian, transcendental style) that the possibility of truth depends on the possibility of agreement, without taking the further step of attempting a definition in these terms.

In the new Study Partners forum I (or my alter ego) respond to a problem raised by my student Joao Magalhaes, regarding the need to refer to truth in order to define knowledge in the traditional way ('justified true belief'). Why not just say:
Joao knows that Mars is the 2nd planet from the Sun if and only if:

1. Joao believes that Mars is the 2nd planet from the sun.
2. Joao has good justification for this belief.
3. Mars is the 2nd planet from the sun.

Now, repeat for 1st, 3rd, 4th, etc.

Repeat for Mercury, Venus, Earth, etc.

Repeat for any other sentence you like, until you get bored.

Job done.
In formal terms, 'true' is a device for propositional quantification. Seen as a mere 'label' the term 'true' enables us to say things like, 'Everything Kyriakos says in his last email is true.' By saying this I am expressing my complete agreement with you. On the matters discussed, we both think the same way. Of course (it goes without saying) we could both be wrong. Maybe the earth is flat after all. But the point is that a definition of truth is not the same as a criterion of truth. A definition of truth doesn't have to give us any additional information (how could it?) about how to determine whether any given statement or proposition is true. It's just a label, a device, and a very useful one at that.

This position is known as 'minimalism about truth'. Another, older, term is the 'redundancy theory' (although there is some debate as to whether these two terms mean exactly the same thing). Some would regard this as equivalent to the rejection of the possibility that truth can be defined. I would prefer to call it a definition. It answers the question, 'What is truth?' in the only way that that question can be answered.

What about 'internal statements'? Wittgenstein's argument against a private language is considered by many to be decisive here, but it leaves a worrying gap (discussed in my article 'Truth and subjective knowledge' Maybe there 'is' something else, something which the label 'true' can never capture, something which each of us 'has' yet cannot express in any language.

All the best,


Functionalism vs behaviourism as theories of the mental

To: Mark S.
From: Geoffrey Klempner
Subject: Functionalism vs behaviourism as theories of the mental
Date: 3rd November 2011 12:19

Dear Mark,

Thank you for your email of 26 October, with your essay for the University of London BA Philosophy of Mind module, in response to the question, ''Functionalism is no better than behaviourism as a theory of the mental.' Discuss.'

This is a very patient (I was tempted to say 'plodding', but in science that's not always a criticism) survey of the various arguments and objections regarding behaviourism and functionalism. I agree largely with the way you have mapped out the terrain. It was inevitable from the start that behaviourism would fail against certain objections where functionalism bravely prevails, and also that against other objections behaviourism and functionalism fare equally well/ badly.

You have also stuck faithfully to the issue of behaviourism vs functionalism, where I might have been tempted to veer off to consider how functionalism relates to, say, connectionism, or to anomalous monism. The only prospect here seems to be a kind of reassurance that one is not looking for (the wrong kind?) of reduction, where supervenience will do. It is one thing to offer functionalism as an umbrella account of the mental, and quite another to pursue projects which involve modelling the mind in terms of concepts from computer science -- something whose point I would be tempted to doubt.

On the contrary, it is clear from the general way the question is formulated that we are considering any version of behaviourism (quite rightly, you limit this to 'analytical' behaviourism) and any version of functionalism. The point that one could be a Cartesian dualist and a functionalist is well taken, but I assume (as you do) that the whole point of the exercise is to resist dualism. (As in the cartoon included in Dennett's 'Consciousness Explained', professor at a blackboard covered in formulae: 'And here a miracle happens!')

But I worry that you may have missed the central point of the question. Your approach assumes that theories can be 'better' or 'worse' in a comparative sense, in the way one might contrast theories of how senility or cancer develop, where the various alternatives are all up for grabs and we are merely concerned with noting pros and cons. Whereas I read the quote in the question in a different way, as a statement that functionalism and behaviourism both FAIL, period, as theories of the mind.

They fail. ''Kruschev was no better than Stalin.' Discuss.' Well, of course, Kruschev introduced all sorts of reforms, bravely criticized his predecessors, but the philosophy he implicitly believed in, Marxism-Leninism, was a total disaster, because...

The point gains some credence from the fact that this is meant to be a one hour essay question (as I've said many times), and therefore the examiners expect you to be able to answer it more or less comfortably in that time. What they don't expect is a page of numbered notes listing all the ways Kruschev was, or was not, better than Stalin!

You can probably gather what would have been the kind of answer I would favour. What is the thing that shoots (claims to shoot) both functionalism and behaviourism down in flames? The person who makes the quote in question clearly believes there is such an objection, and that's what the essay should be about. Either you agree that there is a criticism in the face of which both behaviourism and functionalism miserably fail, or you are fully familiar with the criticism in question and think that it can be resisted. In which case we are then in the game of evaluating pros and cons -- a different essay.

A finesse here might be to indicate why the functionalist 'thinks' they are offering a better alternative to behaviourism, and why, according to a proponent of the knock-down objection, they are sadly deluded. That would gain a mark or two.

A good candidate for the knock-down argument is the problem of qualia, which you describe in various guises. Because this is more central to (my version of) the essay, there would be time to discuss in more detail Wittgenstein's argument against a private language (which I think is compelling, but that's just my view), but also other arguments you mention such as zombies, Chinese room, the million mile high version of Senate House, etc.

How can time make a difference (in the case of the Chinese Room, or Senate House)? I was dying to know the answer to that. Isn't it the utmost parochialism to reject the idea that it might take some gigantic 'creature' a million years to experience a sensation or formulate a single thought? What has time got to do with it? Then again, isn't it parochial to assume that we would ever be in a position to understand/ interpret Senate House's mental states? ('If a lion could speak, we could not understand him', Wittgenstein). I'm assuming that Senate House has arms and legs, or the equivalent (i.e. is an 'agent' with 'its own' needs and goals, not just an information processing device).

Zombies. Would they be different from humans? Massive question! There are two versions of the zombie objection, which make very different points:

Version 1. There might be a zombie double of GK whose behaviour differs in very subtle ways. Most things we can both do, but there are particular tasks at which my zombie double fails, because in order to do them you need that extra 'something' that matter alone, however distributed or organized, cannot supply. The point here is about human ignorance. As would-be materialists, we are merely hypothesizing. We don't know.

Version 2. My zombie double and I are identical in every material respect. But in that case, if I am tempted by the thought experiment to be an epiphenomenalist, wouldn't my zombie double be an 'epiphenomenalist' too?!

All the best,


Hempel's paradox of the ravens

To: Stuart B.
From: Geoffrey Klempner
Subject: Hempel's paradox of the ravens
Date: 2nd November 2011 11:24

Dear Stuart,

Thank you for your email of 24 October, with your essay for the University of London BA Methodology module, in response to the question, 'What is the best response to the paradox of the ravens?'

This is an excellent piece of work with which I can find no real objections.

My main problem (which isn't an objection) is that I just don't believe in 'probability theory'. Not even 'subjective probability' (whatever that means). As an undergraduate, my first ever reading on this topic was the excellent book by A.J. Ayer 'Probability and Evidence', which considers the various pros and cons of the frequency theory, logical relation theory (Keynes) etc. I'm mentioning this as it would be a good book to read. Back then, I wasn't a sceptic but I have become one.

When do we calculate probabilities? and to what purpose? When, and in what way, do we raise a question how much 'support' a theory has? My view would be broadly and loosely Popperian, that any theory which hasn't been decisively refuted is on the table, including theories we do not much like. I would add that preferences for this theory over that theory cut no ice at all. Maybe the choice determines which research project you join, but even there other considerations may override your judgement of the likelihood that the research will prove 'successful' (of course, you can 'succeed' in refuting a theory too). Grant money is always an important factor.

One basic intuition I have is that it is just patently absurd that a white shoe confers any increased probability, however small or even infinitesimal, on the hypothesis 'all ravens are black'. I can see that it would be OK to accept this conclusion as the price for accepting a theory which works well in other ways. No theory is perfect. But it is a flaw, a minor absurdity. It's not a result that we want or can 'justify'. The idea that one could justify the conclusion by some formula seems ridiculous. I'd rather say that if the formula is useful to us in other ways, then we will accept that it occasionally delivers odd or absurd results, but that's a different position.

I agree with you that the question of the nature of probability is a 'major' difficulty. I would add that it's one you can't just sweep under the carpet and say, 'Well, just assume we have a way to calculate probabilities, then...'. One just comes back to the question what probabilities are FOR.

Skill at counting cards in Blackjack (as in 'Rain Man') is one way, objectively verifiable, to tip odds in your favour and make a nice steady income. That's an undeniable fact. We know, in a sense a priori, that we are not going to discover that counting cards actually reduces your chances at winning in the long run (ceteris paribus, one always has to insert that, and provided one can avoid the cameras).

The problem is, in methodology we are tempted by this kind of model -- calculating the odds in order to gain an 'edge' -- where it doesn't really apply. There are too many unknowns, and always will be. What probability theory does do is confer a gloss of rigour and objectivity which adds zero value to the scientific enterprise. There are plenty of opportunities to calculate and apply formulae, but deciding which theory to prefer isn't one of them. As I stated before, all the theories -- even those which look rather implausible -- are on the table. Be prepared to be surprised.

I can therefore totally understand Stephen Hawking's impatience with the philosophy of science and methodology. Bayes' theorem may be useful for all sorts of practical purposes. Of course. But it is practice (or 'praxis') which takes the lead. Not philosophers in armchairs debating how science should be pursued, or what standards a theory 'must' meet.

I guess this will sound rather Feyerabendian, but I'm not really sympathetic to his views either. I appreciate order and rigour in science, and deprecate anarchy. Sociological observations about how science is practiced aren't a substitute for standards and rules. Luckily the editors and editorial boards of professional journals maintain a keen interest in maintaining standards. It's just a pity when these laudable aims are corrupted by the kind of fake 'rigour' which I mentioned earlier. (One thing Feyerabend is good on is observing the slavish way researchers attempt apply 'proper rules and procedures' to situations that don't warrant them, e.g. Masters and Johnson!)

Evidence that is anecdotal, unquantified or unquantifiable, can be valuable too -- in its appropriate place.

I don't see that I am saying anything different from what Aristotle said, that rigour is commendable when applied in the appropriate circumstances. I strongly suspect, therefore, that the whole debate over the ravens paradox is a case of inappropriate application of standards of rigour, which are justified in other circumstances.

All the best,