To: Marcus S.
From: Geoffrey Klempner
Subject: Xenophanes on the limits of human knowledge
Date: 13 June 2005 11:04

Dear Marcus,

Thank you for your email of 2 June, with your first essay for the Ancient Philosophy program, in response to the question, 'What is it to 'know' that something is the case? Can the truth of a scientific theory ever be known? Illustrate your answer by reference to Xenophanes’ reflections on the limits of human knowledge.'

Your final sentence would make an excellent essay question: 'The universe is mysterious and unbounded and thus ultimately unknowable through theory alone.' Discuss.

Xenophanes' warnings about the limits of philosophical speculation suggest a naive picture of knowledge which takes as its paradigm something like, standing in front of a tree and looking straight at it and saying, 'This is a tree.' G.E. Moore did something similar with his famous paper, 'A Refutation of Idealism' where he started by saying, 'This is a hand. And this is a hand...'. The idea being to remind the audience of what is more certain than anything else (more certain than the arguments of philosophical idealists like Berkeley, for example).

Wittgenstein in his last writing, 'On Certainty' has some interesting observations which were provoked by Moore's lecture.

As soon as one looks at human behaviour, as you say, this picture looks rather shaky. The things closest to us can often be the things we least know.

However, there is more than one way of going with this. One obvious point to make is that 'observations are theory laden'. Your observation that your son is 'messy', for example. In a similar way, so long as I stick to tracking the movements of pinpoints of light in the night sky, my 'knowledge' is pretty secure, but it is another thing entirely to give a theory which makes sense of and interprets those observations.

A less obvious point concerns what it is to 'know' a person. Call everything that can be used in order to accurately predict the behaviour of a person, 'people theory'. You are not sure how to interpret your son's messy behaviour because in this case your 'people theory' is inadequate. There are too many things you don't know, which perhaps might only become apparent later. On the other hand, sometimes our people theory can be very good. Judging from the expression on the traffic warden's face, you know with as much certainty as any motorist can know, that if you make any attempt at offering an excuse for parking on a triple yellow line during rush hour you will be instantly slapped with a ticket; whereas, if you adopt the Desmond Morris 'submissive' posture and agree with everything she says, it is just possible that you might get off - this time.

But is that all there is - to knowing a person? When you look into the face of another person, there is something beyond knowledge, which tells you that this is not just a 'thing' which 'behaves' but the possessor of a point of view. Emmanuel Levinas (e.g. in Totality and Infinity) is one philosopher who has followed through the implications of this insight, arguing that the 'otherness of the other' is beyond 'thematized' knowledge. Metaphysics is founded on ethics, not the other way round. That would be one way to make the case that 'the universe is mysterious and unbounded and thus ultimately unknowable through theory alone.'

I'm not so sure about your idea that 'I can't treat knowledge skeptically or doubt its value as knowledge for a single second or I don't really have it.' That seems to be leading inevitably towards total scepticism. It is very doubtful that there is belief so certain that we cannot imagine the possibility of a doubt. But in that case one begins to wonder about the point of the concept 'knowledge'.

To claim knowledge is to claim a certain kind of authority. If you say to someone who inquires, 'I know', that implies, 'You can take it from me.' The fabric of human knowledge is built on this kind of 'trust'. Not unquestioning trust, by any means. The obvious retort to, 'I know' is 'How do you know?' If you know, then you can say how you know. But that does not rule out the possibility of unforeseen circumstances. 'There is a bus in five minutes time because it says so in the timetable and the buses here are very reliable.' But that didn't reckon with a gas explosion in the centre of town which snarled up the traffic for miles around.

In other words, the concept of 'knowledge' has a point, and therefore a place in our language which remains secure despite the exaggerated doubts of the philosophical sceptic.

Zeno is an interesting example. Here, what is in question is our 'knowledge' of philosophical theories and truths. How far do you go with reason, when it clashes with the data of experience? Moore offers a brusque answer to this: 'Berkeley's argument must be wrong because here is a hand!' So, similarly, 'Zeno's argument must be wrong because there goes Achilles!'

All the best,

Geoffrey