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Subsections
8.4 Process Time
Now that the extensive continuum has a relation of extensiveness defined
on it, it is feasible to investigate to what extent the extensive order of
places affects the order of events that occur at those places. Now that
the extensive continuum can be divided up in relation to any given place
by the relations of precedes, succeeds and alternates
with, we want to know how this subdivision is related to the
temporal order of the actualisings in the different regions.
The `extensive continuum' defined above, it should first be noted,
although called `spacetime', has really in itself a temporal component.
It is by itself purely extensive, and totally independent of any changes.
It is just the collection of all places, including the places of all
present and past events and the places possible for all future events. All
these places are gathered together into one vast four-dimensional
continuum. We did not construct it as a union of space and time, where
space is extensive and three-dimensional, and time is one-dimensional and
uniformly flowing. Rather, it is the extensive all-at-once aggregate of
all places possible. Extensiveness is `all-at-once' or `under
the aspect of eternity' because, although events occur each on
its own occasion, all places can be given before there are any
changes (events) that occur at those places. Although, on the view of time
given in the previous section, not all events (especially not future
events) can be given `eternally', this need not restrict our consideration
of their places. The relations of precedes e between places,
and are only between actualities insofar as what is actual is at least
possible. These relations therefore can be given and discussed before any
time or changes, and hence need to be supplemented by further conditions
in order to find any order of events in the places that are related.
What has been done so far is to completely separate in our minds the order
of places in the extensive continuum from any order of events at those
places. But this cannot be the whole story, for if events were to be
completely independent of where they occur in the four-dimensional
continuum, then all events (whether past, present or future) would occur
asynchronously. They would have no temporal relations, let alone causal
relations, between them. Each would just `happen', with no relation at all
to the `happening' of the other events. This may between events which are
in fact causally unrelated, but in general some kind of natural
constraints are necessary to restrain such a free-for-all.
A variety of constraints may be imagined. One suggestion is to order all
events according to some uniform serial time. Each event would then occur
at one and only one time. This uniform serial order could be identified
with some direction of the fourth dimension in the extensive continuum, or
it could be distinct from any such dimension. If it were distinct,
however, we would be effectively constructing a fifth
dimension. This would be a kind of uniformly flowing `hypertime' to order
changes in the four-dimensional spacetime. I don't believe this
`ontologically extravagant' hypothesis should be accepted without
well-founded arguments.
Newtonian time has all events ordered in a uniform serial order which is
identical to the time dimension of the extensive continuum. If the metric
of this continuum is Newtonian in the manner of the previous section, then
the `time direction' is unique. However, as there is considerable
evidence in favour of the theory of special relativity, it is unlikely
that space and time in fact follow the Newtonian pattern.
No Universal Serial Time
Many philosophers and scientists have argued that the theory of relativity
denies the validity of any universal serial order defined by
any metric time. These arguments will be examined in more
detail later in the chapter, but they may be summarised as follows.
According to special relativity, separate observers very often will not
agree on the serial order in which several different `acts of becoming'
did in fact occur. Such differences arise for events which have
`space-like' separations between them.
Because the order of such `becomings' is not invariant for all observers,
Grünbaum [1973] and Reitdijk [1966, 1973] would argue that they
cannot have been `real becomings'. Grünbaum claims, for instance,
that it is only that the various observers `become aware' of the events
at their own various times, with each observer's time depending on his or
her frame of reference.
I admit that in general several observers do not always agree on the
serial or clock order of events with space-like separations. But, I argue,
this is a disagreement only between the different clocks and their serial
times, and not between the real becomings in themselves. When we look more
closely how these serial times arise, we will see that in an important
sense they are derived, and do not affect the separate events
themselves. In ordinary relativity theory, metric times are derived by
considering the observer in relation to the observed action, and analysing
this relation to the actual events which the observer uses to make his
measurements.
I agree that for events with space-like relations, the distincts according
to a metric time of past, present and future are `secondary qualities', as
they depend on the relation of the events to the position and velocity of
the observer. This means that there is not necessarily any
direction in the spacetime continuum for a time axis according to which
all events have a unique serial order.
Figure:
Causal Connections
A line drawn in this spacetime figure indicates a causal connection, and
the time direction is vertically upwards. In circumstances drawn, c
follows a, d follows c, d e, and e b,
but no definite relation holds between events a and b, or between
a and e, or c and b, etc.
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Local Process Times?
One response this conclusion about the impossibility of any universal
serial time, is to point out that this still allows local
orderings, or local process times, that might be based on
past, present and future relations with regard to local events.
By `local events' here, I mean to consider events and their connections
only to their causes and their effects. Within relativity, the relation of
a cause event p to an effect event q is always what we called
`p precedes q' (the `time-like' in relativity theory). This
relation has a definite order, and both the relation and its order are
not changed by choices of observers' frames of reference. To
observe this local order of events, we have
ourselves to be one of these cause or effect events. Only then
can we be sure that the event concerned was either past, present, or
future. Only by looking at the local causal relations can we be sure that
one event is definitely earlier or later than another event. (This view
has the interesting consequence that we be certain that our acts of
knowing are present acts!) Events which are not connected by
local causal chains do not necessarily have any relation of
past or future defined between them. The set of all events are therefore
only partially ordered by the relations of past and/or future,
as pictured in 8.4.
By `partially ordered' as distinct from `completely ordered', is meant
that only some pairs of events will be related, and that there can be
other pairs of events between which no definite relation holds.
In this general position, the process of becoming (kinesis) is
distinguished from any universal time order, and is regarded as
`ontologically prior' to any particular observer's order.
This view has been advocated by Milic Capek (especially in Capek [1971]),
following suggestions from Bergson.
Whitehead and Harris (Harris [1965]) have developed similar positions. To
quote from Harris:
Time is no more than the metric of becoming, which is the presentational
form of the reality which becomes. Capek [1961] explains lucidly how a
single space-time interval between two events may be differently measured
by two observers in different frames of reference, because they use
different metrics (Capek [1961], p. 218). The result is different local
times; but they are secondary characters which do not affect the actual
process of `creative advance'. In a valid sense, time [a metric]
is mere appearance, though the process of events is not. And
this process, we should have learned from Whitehead, is one of
`concrescence', of continuous realisation of `definiteness', wholeness or
form.
8.7
Next: 8.5 One Global Process
Up: 8. A Theory of
Previous: 8.3 Past and Future
Prof Ian Thompson
2003-02-25
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