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Plato's arguments for immortality


To: Ruy R.
From: Geoffrey Klempner
Subject: Plato's arguments for immortality
Date: 21st April 2010 11:05

Dear Ruy,

Thank you for your email of 14 April, with your essay for the University of London Plato and the Presocratics BA module, in response to the question, 'Does either the affinity argument or the final argument in the Phaedo succeed in proving the immortality of the soul? If not, how does it fail?', and your email of 20 April with our query about knowledge and scepticism.


This is not such a bad essay. The best part is where you offer a sympathetic overview of Plato's Theory of Forms which, as you say, makes the immortality of the soul prima facie 'plausible'. The question, however, is, How good are Plato's arguments?

Regarding the first argument, you say, 'The body changes and never remains equal to itself', whereas 'the soul could be compared to what cannot be perceived, i.e. to the Forms that always remain the same to themselves.'

On the face of it there are at least two massive non-sequiturs, in the argument as you present it.

The first non-sequitur, however, is arguably the fault of your exposition rather than Plato. In response to the statement, 'The body changes and never remains equal to itself' surely one could say exactly the same thing about the soul. One day the body is hot, another day the body is cold. So one day the soul is thinking, 'It is very hot today' and another day the soul is thinking, 'The weather is so c-cold.'

So what makes the difference, if any? We say that the body remains 'the same body' despite accidental changes, just as we say that the soul (mind, self) remains the same soul (mind, self) despite accidental changes. The body changes physically, the soul changes mentally. However, what Plato is really trying to get at is that the soul as bearer of changing mental attributes itself has a substance or essence which remains unchanging. The same, of course, would now be asserted about material bodies (contrary to what Plato believed). We are 'stardust, billion year old carbon'. Whereas, for Plato, the Forms provide the unchanging 'substrate'.

However, Plato has something else to say: the activity of philosophy proves that in knowing the Forms, the soul relates to something to which it has an affinity. It could not know the Forms if it was not in some sense 'like' them.

But this takes us straight to the second non-sequitur. To say that the soul has an affinity with, or is 'like' the Forms begs the question in what respects is it 'like' and in what respects 'unlike'. Maybe, as Plato wants us to believe, the soul is 'like' the forms in being non-material. But maybe, also, it is unlike the forms in being capable of going out of existence, while the Forms are not capable of going out of existence.

The second argument also, arguably, is based on a non-sequitur. A body can be alive or dead. A dead body is still a body. Whereas a soul 'partakes essentially in the Form of life'. But what does this mean? It means that the soul is not the kind of thing that can be 'dead'. A dead soul would be contradiction in terms. Or, in other words, a soul is 'deathless'.

However, it doesn't follow from the premise that the soul is deathless, that the soul cannot be destroyed. It would be consistent to hold that the soul, unlike the body, is deathless so that at death, the body becomes dead, while the soul goes out of existence altogether.

Knowledge and scepticism

It is a very old argument, that the sceptic cannot assert, 'There is no knowledge' because we can ask the sceptic how he know this. I would accept that there is no way round this, so far as assertion is concerned. To assert that P implies that you know that P. Otherwise you are just Twittering.

The same holds for each premiss in the sceptic's argument, whatever that argument may be. E.g. as you state, 'there is an inexorable gap between experience and reality'.

So the only course for the sceptic would be to say, 'Either I know nothing. In which case I must shut up and not say anything. Or the only thing I know is that there is an inexorable gap between experience and reality. In which case, having made that one statement, I must shut up and not say anything.'

I don't think that this is the argument that Wittgenstein had in mind.

I do think that Lewis's claim that knowledge is a 'contextual notion' has something in common with Wittgenstein's approach. As you say, we worry about scepticism only when we take the familiar use of the term 'know' out of the context which gives it a use, a 'meaning'.

All the best,