Thursday, May 9, 2013

McTaggart's proof of the unreality of time

To: Mark S.
From: Geoffrey Klempner
Subject: McTaggart's proof of the unreality of time
Date: 26th January 2010 13:30

Dear Mark,

Thank you for your email of 17 January, with your essay for the University of London BA Metaphysics module, in response to the question, 'Does McTaggart have a convincing argument for the unreality of time?'

This is a well-argued essay whose conclusion I happen to disagree with -- but more of that later.

I spent too long puzzling over your Tolstoy quip (I do recall the original quote, about families being unhappy in different ways but can't remember where it's from). The question says 'convincing'. It is important to note that the terms 'valid/ invalid', 'sound/ unsound' have a precise sense in logic, to which one has to defer in philosophical writing:

An argument is valid if and only if, by virtue of its form, it is impossible for its premisses to be jointly true and the conclusion false.

An argument is sound if and only if it is valid, and the premisses are jointly true.

It follows from this that an argument can be unsound in just two ways:

a) It is formally valid, but one or more of the premisses is/ are false.

b) It is formally invalid.

This increases to four ways if we consider the possibility that the conclusion is, as a matter of fact, true, or is as a matter of fact false, either in case a) or case b).

The problem with applying the term 'valid' to philosophical arguments is that ANY argument can be rendered formally valid (you just adjust the premisses). Nor is it a criticism of a philosophical argument that it is formally invalid -- most are.

Can a sound argument be unconvincing? Yes, arguably, if we consider the conclusion to be a paradox.

It seems that you want to say (at least) that McTaggart's argument is unsound, but the conclusion is true. But you also want to say that McTaggart has (partly) succeeded in putting his finger on what is wrong with the conception of time according to which the A-series is real. The idea of 'partly putting one's finger on' is one which isn't captured by the four-fold classification above. -- So much for the limitations of logic.

The way you go about your task, considering objections from Mellor and Lowe is illuminating. I think you could have said more about Mellor's version of the B-series theory, which includes an explanation of why we use terms such as 'past', 'present' and 'future', by considering the perspective of the agent. It looks as if Mellor has accounted for everything.

I would like to offer a perspective on this, which places the argument over the 'reality' of time in a wider context.

It does seem that in considering whether McTaggart's argument is 'convincing' or not, one ends up in a futile debate about whether time, as described, is 'real' or not. Evidently, Mellor thinks so and so do you. Whereas I would regard it as evidently false. In other words, one philosopher says, 'It's real enough for me!' while the other says, 'It isn't real enough for me!'

What is at stake, is, as you observe, the present. I am now typing these words which will later be pasted into an email. That statement has truth conditions, and the truth conditions refer only to B-facts. Yet so far as I am concerned, that statement is already false. I am not now typing those words. Every time is a 'now', but one time, and one only, is *now*.

What is the underlying assumption behind Mellor's view? It is the claim made by Wittgenstein in the Tractatus: 'The world is all that is the case.' There is nothing more to reality, or what is real, than what can be stated truly. Nothing escapes the web of propositions. All possible facts are contained within the compass of 'what can be said'.

Lowe offers truth conditions which apparently 'save' intuitions about A-facts, but the response of the B-theorist would be to say that token-reflexive 'truth conditions' are only such by name.

In Naive Metaphysics (an early version of which was read by Lowe), I describe a 'reality' which allows room for both views about time, which link to parallel views about the self or 'I'. All facts about GK are facts about 'I', but there is one additional fact about 'I', which is that 'I am GK' (cf. Nagel's discussion of 'I am TN' in 'The View From Nowhere'). The theory amounts to the claim that solipsism is both true and false. The world IS my world (the subjective world) and it is also true that the world is not my world (the objective world).

This is a 'contradiction' which I am prepared to tolerate, for the sake of 'including everything'. (A theory which does not include everything isn't a 'metaphysic'.) Conclusion: reality is contradictory.

What Mellor says about time and agency is valid for the objective world. Anything I state regarding 'now' or 'the present' can be understood in terms of the formal requirements for agency in relation to the temporal series. But there is one fact which this does not capture, namely that *I* am the agent in question.

It's fair to say that I stuck my neck a long way out in writing that book. I would now propose a slightly more modest view, that reality cannot be captured in its totality, from whichever direction one considers it. Science rightly emphasises the objective (B-series) view of time. But that's not the whole of reality. In addition, there is something that cannot be 'said' but only 'shown'.

All the best,

Geoffrey