The Causal Structure of the World
notes by
F.C.T. Moore
If we wish to represent the world as a causal nexus, we may make a geometrical
model: a space whose points represent events, and in which these points
are linked by lines representing a causal connection. Such a space
is not Euclidean. It will be a space which may be bounded or bent
or discrete and which may have holes in it. It may even have booby
traps or oubliettes. The Universe, considered
as a causally ordered entity, might be a single land mass, or it might
consist of a number of continents, perhaps tenuously
connected. There might peninsulae, islands
and archipelagoes of causal structure, rather
than the homogeneous nexus
of which Kant cleanly dreamed.
One kind of "causal space", therefore, would mean that there is some causal
path between any two events (just as in ordinary Euclidean space there
is a line between any two points). This seems to mean that we could
never exclude in principle the existence of a causal connection between
apparently unrelated kinds of event, though we might have good empirical
reasons to exclude them.
A causal space of a Laplacean kind has strong
characteristics:
The main claim is:
From a complete state description of the Universe at one time, the exact
state of the Universe at any later time could be calculated, using the
laws of nature
Since the state description is supposed to consist of statements about
the position, mass and momentum of every elementary particle, Laplacean
determinism, in this form, has an assumption:
The universe consists of indivisible atoms distributed in space and interacting
according to the laws of nature
These statements would enable one to infer future states of the universe
provided that we have a general method of calculating the interactions
of the particles described. So there is a further assumption:
There is also a corollary. If all future states of the universe
are fully determined in this way, then pure physics would be enough.
Other sciences, or other ways of describing the universe, would be superfluous.
There arises the idea of "reductionism":
Any description of features of the universe not consisting exclusively
of statements of the position etc. of its atoms can be reduced to
a set of such statements, and is equivalent to this set.
The last of these principles, "reductionism", is viewed by some as a metaphysical
prejudice. Thom writes (Structural Stability and Morphogenesis,
pp. 158-9): "Contrary to what is generally believed about the two traditionally
opposed theories of biology, vitalism and reductionism,
it is the attitude of the reductionist that is metaphysical. He postulates
a reduction of living processes to pure physicochemistry, but such a reduction
has never been experimentally established. Vitalism, on the other
hand, deals with a striking collection of facts about regulation and finality
which cover almost all aspects of living activities, but it is discredited
by its hollow terminology (e.g. Driesch's "organizing
principle" and "entelechies"), a fault accepted
and exaggerated by subsequent teleological philosophers (Bergson,
Teilhard de Chardin). We must not judge
these thinkers too severely, however; their work contains many daring ideas
that those who are hide-bound by mechanistic taboos
can never glimpse ... The dispute is really pointless; many of the physicochemical
properties of matter are still unknown, and realization of the ancient
dream of the atomist - to reconstruct the universe and all its properties
in one theory of combinations of elementary particles and their interactions
- has scarcely been started (e.g. there is no satisfactory theory of the
liquid state of matter). If the biologist is to progress and understand
living processes, he cannot wait until physics and chemistry can give him
a complete theory of all local processes found in living matter ..."
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