Monday, February 18, 2013

Stoics on eternal recurrence, Epicurus on sensations

To: Pearl K.
From: Geoffrey Klempner
Subject: Stoics on eternal recurrence, Epicurus on sensations
Date: 30th April 2009 12:01

Dear Sachiko,

Thank you for your two emails of 29 April, with essays for the University of London module on Post-Aristotelian Philosophy, in response to the question, 'What motivated the Stoic doctrine of eternal recurrence? Were the Stoics able to solve the philosophical problems it implied?', and the question, 'Evaluate Epicurus' claim that all sensations are true.' I am responding quickly, as your exam is very soon.

Eternal Recurrence

This is a great topic. If I were answering this question, I would probably found a way to mention Nietzsche who famously took up the Stoic doctrine of eternal recurrence, offering (in 'The Will to Power') an admittedly somewhat specious argument based on the assumption of determinism together with the assumption that the universe is composed of immutable atoms. According to Nietzsche, it is inevitable that at some point in the future the precise configuration of atoms will repeat a previous configuration. According to determinism, the entire history of the universe must repeat from that point onwards.

Nietzsche's interest is (arguably) the same as that of the Stoics: to provide a powerful statement of fatalism, the ability to embrace the eternal recurrence being a test of a certain kind of individual.

A fatal objection to Nietzsche's argument for the eternal recurrence, however, is that granting determinism there is no mathematical necessity that the 'same state' will ever repeated, even given infinite time. This is a more effective criticism than the one you give, based on mere empirical considerations (the theory of Relativity). In evaluating a philosophical theory, one is allowed to consider possible universes where the theory might have held: in the present case, a Newtonian universe, rather than an Einsteinian one.

However, it is important to note that the question doesn't ask for 'criticisms of the theory of eternal recurrence'. In an exam, this would be marked as 'irrelevant'.

What motivated the Stoic doctrine? I said that one motivation is the same as the reason that motivated Nietzsche, namely the desire to give powerful expression to belief in fatalism. This it undoubtedly does. Of course, it does not follow that if you are a fatalist you have to believe in some version of the eternal recurrence. Indeed, you can be a fatalist and reject determinism. If the universe just IS the way God intended it to be, at ever moment of historical time, then belief in determinism is not required. Things happen, as God decrees.

Another possible motivation which you don't mention (admittedly somewhat speculative) is that the Stoic doctrine of eternal recurrence reconciles belief in a finite cosmos with the infinity of time. Quoting Milic Capek, you comment on this in relation to the Leibnizian principle of the identity of indiscernibles. For the Stoics, it is history that is repeated, while time goes ineluctably on. This entails, as you state, an 'absolutist' rather than a 'relational' view of time. The idea of 'cyclical time' is a philosophically more sophisticated notion, which is not required and is (arguably) inconsistent with the doctrine of recurrence.

Another point you discuss is the Leibnizian principle that this world is the 'best of all possible worlds'. If God is going to make the world again, there is only one way to do it, namely the best possible way. So the result must be the same as before. However, this looks at face value to be a very suspect argument. If variety is considered a valuable attribute of any universe, then surely you could just as easily argue that the 'best of all possible worlds' requires an infinite sequence of infinitely variegated cosmoses.

This is what Leibniz would say. The crucial difference between Leibniz and the Stoics is that for Leibniz, the deity is *outside* the world, whereas the Stoics held a view much closer to pantheism, where the deity is a necessary constituent of the world itself. Having the essential nature that it has, the deity cannot alter from one cycle to the next.

(For this reason, I think you need to look again at your statement, 'remember, God is the epitome of reason and wisdom, therefore he always chooses the design of the 'best possible world' each and every time'.)

As you state, the Stoic doctrine of eternal recurrence creates a problem analogous to the 'problem of evil' in theology: how to reconcile God's 'goodness' with the existence of evil in the world. Seneca's response is comparable to the view of theologians that God chose a universe which would create the 'best possible souls', by creating the necessary conditions of adversity and moral challenge. (It is worth noting, as an aside, that this is of course a problem which did not worry Nietzsche, who has no interest in defending the 'best possible world' view.)

I don't understand your objection regarding eating a peanut butter sandwich for breakfast. If you chose peanut butter last time around, then you can't 'change your mind' this time. In a determinist universe where would such a change have originated? Take a more extreme example. Let's say that you are a good person and would never push an old lady in front of a bus for fun. Might you, in a future universe where you had 'free will'? Surely, we WANT it to be the case that our actions proceed reliably from our character. That's what the Stoics believed, hence the enormous emphasis on the development of 'virtue'.

All sensations are true

The main question that you need to address here is what is meant by the 'truth' of a 'sensation'. At face value, the claim, 'all sensations are true' would be read by a modern philosopher as a classic statement of the belief in 'private objects', or 'Cartesian mental events' in the sense attacked by Wittgenstein.

On this reading, I cannot be wrong about the content of my present experience, because there is no room for a 'gap' between my mind and the 'object' in question. In ordinary language, we accept that if someone says, 'the sky seems orange to me', then they cannot (if they are being truthful and not intentionally lying) be making a false judgement. Whereas, if they say, 'the sky is orange' their judgement can be false. (E.g. the subject has just taken a tab of LSD.) This common sense distinction, refracted through a false philosophical theory, is the basis for the sense datum theory of perception.

On this questionable theory, it makes perfect sense for me to give a special name for the colour that the sky has for *me*, say, 'BlueGK'. It would be possible for the subjective quality of my experience to change overnight, so that what looked 'BlueGK' today looked 'RedGK' tomorrow, even though everyone still agreed that the sky was 'blue'. (I am describing the 'spectrum inversion' hypothesis.) You have done enough philosophy by now to recognize that we are dealing here with the tricky issue of 'qualia'.

I used the term 'Cartesian mental event' because it could be argued that this idea traces back to Descartes' claim that statements about how things seem to me (e.g. 'I have a sharp pain', 'I see a red patch') are incapable of being doubted.

It is possible that Epicurus' thinking on the nature of sensation anticipated Descartes here, that is to say, he was indeed tempted by the idea of incorrigible 'private objects'. However, other things you say contradict this picture. At the beginning of your essay, you describe Epicurus' theory of perception -- surprisingly modern in its structure, and a great advance on Empedocles' theory -- where sensations are regarded not so much as 'Cartesian mental events' but rather as physical events resulting from a repeatable causal process. Whether an object is red, or round, or smells or tastes a certain way, or makes a certain kind of sound is a reliable (because repeatable) consequence of the physical way that object is. That's why we regard the sensation as a 'datum', a piece of hard factual knowledge, and the starting point for making judgements about the nature of that object, on the basis of our conceptual knowledge.

Similarly, one might argue, an ear, an eye, a nose is a physical entity with a structure which is reproduced many numbers of times, so that it is hardly surprising that what looks red or round to one eye will also look red or round to another eye.

Given this starting point, however, there are still ways that perceptual judgements can go wrong, and the question is how Epicurus is able to account for this. As you report, Epicurus discusses the question of possible 'movement connected with the perception of images but distinguished from it'. Your example of the flash of light doesn't really do this idea justice. We are not just concerned with error in identifying a horse as opposed to an ox. That is a matter of judgement, and it is accepted that judgements can be false. The question is how a sensation can be 'false', that is to say, not look the way it is supposed to look.

Here, I would interpret 'movement connected with the perception of images but distinguished from it' as referring to background conditions of perception. In saying that the process of perception reliably produces the same sensation each time we view the same object, we are assuming normal conditions of perception. However, if, e.g. the quality of the light is altered, or something happens which affects the normal functioning of one's eye, then the process of cause and effect will result in a sensation which does not have the quality that it 'ought' to have.

Much of what Epicurus says seems to be a reasonably coherent version of the principle of empiricism. Knowledge of the external world is impossible unless you have some reason to trust the data. We should be prepared to let nature prove our judgements or theories wrong by accepting the evidence of our senses. However, there will inevitably arise occasions where we have to override our perceptual judgements -- for example, in the situation just outlined where we have reason to believe that the 'background conditions' for perceptual are not normal or ideal.

Given all this, Epicurus' claim that reason cannot refute the senses because it depends on them is exactly what one should say. Here is what amounts to a direct rebuttal of claims made by, e.g. the Presocratic atomists, who held that philosophical reason demonstrates that the beliefs arising from the senses are false (e.g. the belief that there exist colours). To say that reason cannot refute the senses is not to make the extravagant claim that we can never be wrong in what we seem to perceive, but rather to state that in the process of gaining knowledge of the external world, reason and perception have to work together.

All the best,