Published online by Cambridge University Press: 12 April 2010
I want to consider some features of the position put forward by Julian Barbour in The End of Time that seem to me of particular philosophical interest. At the level of generality at which I'll be concerned with it, the view is relatively easy to describe. It can be arrived at by thinking of time as decomposing in some natural way linearly ordered atomic parts, ‘moments’, and combining an observation about the internal structure of moments with an epistemological doctrine about our access to the past. The epistemological doctrine, which I'll call ‘Presentism’, following Butterfield, is the view that our access to the past is mediated by records, or local representations, of it. The observation is that the state of the world at any moment has the structure of what Barbour calls a ‘time capsule’, which is to say that it constitutes a partial record of its past, it is pregnant with interrelated mutually consistent representations of its own history.
1 London: Weidenfeld and Nicholson, 1999.
2 The Mott-Heisenberg analysis of a-decay is his explicit model.
3 My present experience is coloured by memories, including memories of myself remembering, and the way those memories coloured experience under them.
4 ‘The Unreality of Time’, Mind, New Series, 68, 10. 1908. McTaggart distinguished two series in which events were ordered, an A-series, which ordered them in terms of their relations to the present moment, and a B-series, which ordered in terms of their unchanging, eternal, temporal relations to one anotherGoogle Scholar.
5 No restriction on the form such records take is presumed; photographs, recordings, footprints in sand, traces in memory… ‘But what is the past? Strictly, it is never anything more than we can infer from present records. The word “record” prejudges the issue…we might replace “records” by some more neutral expression like “structures that seem to tell a consistent story”.’ (, Barbour, op. cit., p. 33Google Scholar)
6 ‘Quantum Mechanics for Cosmologists’, in Speakable and Unspeakable in Quantum Mechanics, Cambridge University Press, Cambridge (1987), p. 117–38Google Scholar.
7 Just as, in a Leibnizian universe, there is not any genuinely external dimension in which the monads are ordered; spatial relations, such as they are, arise from relations among the intrinsic properties of monads. This is why I call the move Leibnizian.
8 The procedure identifies places across time in a way that minimizes resulting overall motion of bodies, and it turns out that both Newtonian time, and time in General Relativity are explicitly definable in this way from the dynamical evolution of the universe.
9 All those ascribed a non-zero amplitude by the quantum state.
10 E.g.: is time atomic? How big is the smallest time-capsule? Endless technical details, and questions of motivation.
11 Barbour is up-front about the conjectural nature of the assumption that the i/-function will end up clustering on time-capsules; the position could fall on this purely technical consideration.
12 At least in the case of monads, their internal structure really does reflect the actual network of relations, though it turns out that they are internal.
13 Suppose that t is the time at which we prepared the particle, that t* is the instant, 5 seconds later, at which it is first detected outside the nucleus, and that there is nothing to place the emission event at any moment between t and t*.
14 Personal communication.
15 ‘Quantum Theory as an Indication of a New Order’ in Wholeness the Implicate Order, Routledge, New York (1980), p. 149Google Scholar.
16 Or, in Barbour's case, the appearance of it.
17 The internal structures of monads have to be unfolding in sync with one another in a way that gives rise to the impression of a common external cause.
18 The other difference, of course, is that Barbour describes his view as a denial of the reality of time, where Leibniz describes his as a view about the true nature of space.
19 Butterfield, BfPS, forthcoming. The article surveys the whole of Barbour's work and situates it with respect to the contemporary philosophical literature about time.
20 Bell himself dismisses the view on the grounds that it gives rise to scepticism: “Everett's replacement of the past by memories is a radical solipsism -extending to the temporal dimension the replacement of everything outside my head by my impressions, of ordinary solipsism or positivism. Solipsism cannot be refuted. But if such a theory were taken seriously it would hardly be possible to take anything else seriously.” ( , Bell, op.cit., p. 136)Google Scholar.
21 There are two ways to think of the relationship between records and measurements; you can think of measurements as interactions that create accessible records of not otherwise accessible facts, or you can think of records as the presently accessible results of measurements on the past.
22 The only thing we can conclude from the result of an individual measurement is that the measured system is not (or, is with measure zero probability) in an eigenstate of the measured observable with eigenvalue orthogonal to the one observed.
23 There are philosophical positions (sometimes called ‘direct realist’) that hold that both perception and memory, are representationally unmediated ways of apprehending external things and the past. So long, however, as we are spatially localized things picking up information about our environments from local causal interactions, Presentism is the epistemology built into our physical theories.
24 Or, a formulation I prefer, the classical world remembers its earlier states, where the present state of the quantum universe is merely a memento of its past.
25 I have argued, independently that we can even find in the relations among temporally situated representations of time—of which time capsules are instances—something that satisfies McTaggart's desiderata for passage (‘The Reality of Time’, ms).
26 There are a variety of accounts in the literature, all presupposing some form of causal determination or nomological covariation.
27 The derived intentionality of artifacts like linguistic structures, designed with representational intent isn't obviously applicable (unless the intent is God's, and Barbour wants to convict him of malice). One might surmise, however, from some of his remarks about consciousness, that Barbour inclines towards some sort of irreducible intentionality derived from their relations to human minds.
28 There are a whole set of questions, for instance, about what Barbour means when he talks about selves; he speaks sometimes as though he is a self-aware time-capsule, and sometimes as though he thinks he is temporally extended, ‘present’, somehow, in different time capsules.
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