CHRISTIANS, and indeed religious people in general, often seem
to be frightened of causes. Cause and effect are the very substance
of science. Causes, especially, are the instruments of scientists.
They seem to show that the decisions that we thought were the
result of our own free choice were, in fact, the result of quite
other things - genes, environment, chemicals, or even atoms. We
imagine that we are free, but in fact our actions are entirely
caused by other factors. Where did this strange pessimism come
from?
Two hundred years ago this year, one of the world's great
science books was first published in Paris, Essai philosophique
sur les probabilités by Pierre-Simon Laplace. It is the
crucial work for the science of probability, but it is still more
influential for just two sentences in its first chapter, which set
out a word-picture or thought-experiment that is the foundation of
modern determinism.
This popular basis for scientific atheism is still widely
believed, and is - most probably - complete nonsense.
Laplace wrote:
We may regard the present state of
the universe as the effect of its past and the cause of its future.
An intellect which at a certain moment would know all forces that
set nature in motion, and all positions of all items of which
nature is composed, if this intellect were also vast enough to
submit these data to analysis, it would embrace in a single formula
the movements of the greatest bodies of the universe and those of
the tiniest atom; for such an intellect, nothing would be
uncertain, and the future, just like the past, would be present
before its eyes.
In other words, if we knew everything about the world now and
all the laws of nature, then we could know the exact state of the
world at any time in the future. Or again, if we knew the exact
position of every single particle and the forces acting upon them,
then we could know the exact position of any and every particle at
any time in the future. This is what is commonly called the Block
Universe, where the future is as determined as the past.
Time is treated as a fourth dimension, essentially equivalent to
the three dimensions of space. If you imagine moving along the time
axis in the same way as along any of the space dimensions, then you
can begin to imagine a complete, eternal, static or block universe.
Although we ourselves are constrained to one particular time and
space, we can, through this picture (it is suggested), see that
time and free will are illusions when set against this fixed
reality.
WHILE admiring the extraordinary and enduring influence of this
simple idea, we should recognise that it is not a scientific
theory, for it can in no way be tested; nor is it a proof, for it
cannot be demonstrated. It was persuasive initially partly because
it expressed the hopes of its age of explaining everything in
scientific-mechanical terms, and partly because it was so
succinctly expressed by a renowned scientist, second only in
reputation to Isaac Newton. It is important to remember, however,
that it is just a clever idea, and, I would argue, a wrong one.
The informal philosophical truth on which we base all our
science and inquiry, at whatever level - namely that every thing or
event has a cause - should not be confused with the notion that
everything (i.e. the entire universe) has a cause. It is Laplace's
first sentence that is most in err0r. The entire universe is
not the cause of its own future. That is a
misunderstanding of the term "cause".
THE great thing about causes is that they can make sense only if
we exclude information, and do not take into account
everything. A good example comes from cricket, in the use of
Hawk-Eye technology to decide where the ball would have struck,
after an lbw appeal. It gathers the information, adds the laws of
motion, and predicts exactly where the ball would have ended
up.
In this, it follows the precise procedure that Laplace had in
mind. But - and this is the crucial difference - it can do so only
by ignoring vast amounts of information, and concentrating only on
what is relevant.
The scientific and philosophical understanding of causation is
wonderfully complex, but there is always a necessary
incompleteness, even vagueness, to the whole idea. What do we mean,
for example, by relevance?
If Laplace were right, that a complete analysis of atoms would
explain and predict everything, then one of the great modern models
of causation (popular among atheists), namely, Darwinian natural
selection, would be revealed as every bit as illusory as choice and
free will.
If all causation were at the level of physics
(Laplace), then there is nothing left for causation at the level of
biology (Darwin).
ALL this is complicated, but it is important that believers
should not be browbeaten by earnest determinists. The next time you
encounter Laplace's vision of the Block Universe - and if you read
any popular science, you cannot fail to do so - remember to say to
yourself: "Every thing may have a cause, but not everything."
If a cause cannot make sense, nor be scientifically tested,
unless it excludes information, then it cannot also be
taken to be something that includes everything.
Think of causes as explanations, and it becomes easier to see
that "everything", or even "the exact state of the universe at
such-and-such a time", would be worthless answers. They do not
explain anything. Nor then (and we are still using picture
language) can they constrain, control, or determine anything.
Laplace's vision of completeness is only a vision, and an illusory
one.
If "everything" is neither the cause nor the effect, this leaves
you, me, and everyone else more than enough room not to have our
life predetermined, and to allow us to be agents, able to cause
things to happen by our own will and decisions.
The Revd Nicholas Turner is the Rector of Broughton, Marton,
and Thornton, in Bradford diocese. Ebook versions of Laplace's
works are available free on the internet. For more complicated (and
often suspect) refutations of his argument, search for "Laplace's
demon", the thought-experiment's popular, but unfair,
title.