If I say that the strength of a triangle is due (in part, obviously) to the
arrangement of its legs, have I "reduced" the the triangle's strength to the
properties of its legs? Well, that depends on what one means by reduced. If
by reduced, one means that only that one has made mention of the legs in the
course of explaining a property of the whole, then, the explanation is, indeed,
a reduction. If, on the other hand, the requirement of reduction is that the
explanation make mention only of the properties of the individual parts, then
the explanation fails as a reduction, because an "arrangement" of legs is not
strictly speaking, a property of the individual legs, themselves. "An
arrangement" is already a nominal emergent of the legs. On this account, an
explanation of the properties of a whole by reference to a temporal or spacial
arrangement of its parts is in fact an explanation of one emergent property by
another.
This seems to open up a crack in the argument that non-reductive physicalism
violates the causal closure of the physical. For, it suggests that any
complete explanation of properties at one level in terms of properties of
another would have at least three steps. The first step is the emergent to
emergent step, showing that nominal emergent properties lead to other emergent
properties. The second step is to identify the causes of the arrangement,
which could be physical causes. The third step is to show why it is that
arrangement in this way facilitates those properties. These, too, could be
physical causes. So, if we now allow into our concept of causal closure of
the physical to include the idea that arrangements of parts are constraints on
the motions and positions of those parts, can't have a dual account where
triangleness causes strength and the physical properties of the elements of a
triangle (the legs and the joints) cause THAT [triangleness causes strength].
Causal closure of the physical is complete because if nominally emergent
properties such as temporal and spatial arrangement are allowed into the family
of physical causes, we just have a case of physical causes causing physical
causes.
Nick
Nicholas S. Thompson
Emeritus Professor of Psychology and Ethology,
Clark University ([email protected])
http://home.earthlink.net/~nickthompson/naturaldesigns/
http://www.cusf.org [City University of Santa Fe]
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