[ Pobierz całość w formacie PDF ]

specific model of explanation is needed to state the condition.
Laws, explanations and the reduction of possibilities 183
References
Arnold, V. I. (1978) Mathematical Methods of Classical Mechanics, New York: Springer
Verlag.
Berger, V. and Olsson, M. (1973) Classical Mechanics, A Modern Perspective, New York:
McGraw Hill.
Corben, H. C. and Stehle, P. (1957) Classical Mechanics, New York: John Wiley & Sons,
Inc.
Dubyago, A. D. (1961) The Determination of Orbits, New York: Macmillan.
Koslow, A. A. (1992) Structuralist Theory of Logic, New York: Cambridge University
Press.
Leeds, S. (2001)  Possibility: physical and metaphysical , in C. Gillett and B. Loewer
(eds) Physicalism and its Discontents, Cambridge, UK: Cambridge University Press.
Mellor, D. H. (1995) The Facts of Causation, London: Routledge.
12 What is wrong with the
relational theory of change?
Gonzalo Rodriguez-Pereyra
1
Things, or objects, change their properties: a banana is green one day and
some days later it is yellow; a kettle is hot at one time and some time later it
is cold; a person is bent at the times when he or she is sitting and straight at
the times when he or she is standing. How can a banana be both green and
yellow all over? By being green and yellow at different times, of course, since
for something to change it must have incompatible properties at different
times.1 But how is change possible? Given that certain properties cannot be
had at the same time, why is it possible to have them at different times? Why
and how does a difference in time make possible what is otherwise impossible?
Why is it not a contradiction that a banana is green and yellow, i.e. not green,
all over at different times? This is the problem of change, and several solutions
have been proposed.
Some philosophers, such as David Armstrong (1980) and David Lewis (1986:
202 4), think that a difference in time makes possible what is otherwise impos-
sible because a difference in time is also a difference in parts. No doubt it is
possible for a thing to be green and for another to be yellow, and this, according
to these philosophers, is what happens in the case of the banana: it is one thing
that is green, a certain temporal part of the banana, and another one that is
yellow, another temporal part of the banana. Others, among them presentists
such as Mark Hinchliff (1996: 123 6), think that a difference in time makes
possible what is otherwise impossible because a difference in time is also a
difference in tense. No doubt it is possible for a thing to be green and not to
be other colours and this, according to these philosophers, is what happens
in the case of the banana: the banana is just green and any other colour is a
colour that the banana has had or will have.
Yet other philosophers propose yet another solution. Hugh Mellor, in his Real
Time (1981: 111 14), thought that a difference in time makes possible what
is otherwise impossible because a difference in time is always a difference in
relata. No doubt it is possible for a thing to bear a relation to a thing and an
incompatible relation to a different thing, and this, Mellor thought, is what
happens in the case of the banana: it is one thing with respect to which the
What is wrong with the relational theory of change? 185
banana is green, time t, and another thing with respect to which the banana
is yellow, later time t2 .
Mellor in 1981 held what I call the relational theory of change. In its canoni-
cal version, the theory holds that changeable properties are really relations
between things and times. It thus explains the change of the banana by
saying that it bears the relation green-at to a time t and the relation yellow-at
to a later time t2 . Thus, according to this theory, although it is impossible to
be green and yellow all over at the same time, it is possible to be green and
yellow at different times, because this involves different relata. The relational
theory, also held by Peter van Inwagen (1990), has recently been abandoned
by Mellor in his Real Time II, in which he argues against it. In this chapter I
shall try to show why the relational theory fails to account for change, and I
shall also criticize the arguments of several philosophers, including Mellor,
against the theory.
My aim in this chapter is to present a new argument against the relational
theory of change. Since the relational theory has already been rejected by
many philosophers, before presenting my own argument against it I shall
show why these other arguments against it are not effective. Thus, in Section
2, I shall say something more about the problem of change and the relational
theory; in Sections 3 6 I shall criticize the arguments of several contemporary
philosophers, including Mellor, against the relational theory; and in Section 7
I shall give my new argument that the relational theory fails.
2
The problem of change, which the relational theory tries to solve, is sometimes
called the  problem of temporary intrinsics . The problematic entities are sup-
posed to be properties; they are temporary because they are not had by their
subjects at every time, i.e. they are changeable properties; and they are intrinsic
because if a thing has such a property this is supposed to be independent of
any and every relation the thing in question bears to anything.
But taking the problem of change to be the problem of temporary intrinsics
is making relational change either inexistent or unproblematic.2 Relational
change, however, is as existent and as problematic as intrinsic change. That
there is relational change is proved just by giving examples, i.e. a is hotter
than b at t and a is colder than b at t2 . This example, however, does not prove
relational change to be something over and above intrinsic change; for here
relational change is clearly supervenient upon intrinsic change of a and b,
namely change in a a s and b s temperatures. But there are relations, such
as some spatial ones, which supervene upon no intrinsic properties of the
relata. Thus, that a and b are 2 miles apart at t and they are 1 mile apart at t2
is genuine, irreducible relational change on a relational theory of space. And
on a substantival theory of space, change of distance is explained in terms of
change with respect to the region occupied, so that when a occupies region x at
186 Gonzalo Rodriguez-Pereyra
t and it occupies region y at t2 there is genuine, irreducible relational change.
So, in general, spatial change is genuine relational change.
Whatever one s theory of space, change of distance is as problematic as
intrinsic change. How can a and b be both 1 mile apart and 2 miles apart?
By being 1 mile apart at a time and being 2 miles apart at a different time,
of course. But how is this change possible? Change consists indeed in having
incompatible properties or relations at different times, and so the problem [ Pobierz całość w formacie PDF ]