_A modern duel: Einstein and Eddington v. Bergson and Whitehead_
In this battle over the importance of time and process great names
stand out as representatives of the two opposed views: Einstein
and Bergson, with their lieutenants, Eddington and Whitehead. The
two leaders use very different methods. Einstein, as mathematical
physicist, suggests that physical laws can best be expressed if we
assume that space and time are so similar that physics can make no
absolute distinction between them. Thus in relativity theory the
symmetry of space involves the symmetry of time, and therefore the
reversibility of physical laws, as has been shown by Birkhoff.
Bergson, as biologist and philosopher, denies that the view of time
which is implicit in relativity mathematics is adequate when a wider
range of experience is taken into account.
Einstein starts by excluding all but a very narrow range of physical
experience, and finds that he can make successful predictions about
light and gravitation by treating the irreversibility of the passage
of time as of no importance for scientific measurements. Bergson, by
studying a wide range of biological and subjective experience, comes
to assert the existence of a creative process, though the inherent
limitations of the intellect and of science may leave the essence of
this process outside their reach.
Both protagonists have left their flanks exposed, by omitting to
present their view as a consistent logical system, Einstein because he
is concerned only with the equations that can be empirically tested,
and Bergson because his chief interest is non-intellectual. It is here
that their lieutenants step forward to develop the two points of view,
and hence to intensify the conflict.
Eddington provides a logical basis for the theory of relativity and
reveals that the significance of physical laws is not quite what we
used to think. They are, he argues, identities which the human mind
discovers in its search for something permanent that it can call
_matter_ beneath all the changing appearances of the world. We have
made matter the real thing by demanding permanence or indestructibility
as the basis of physical reality. Now that we know that we have done
this it need not trouble us too much to find that absolute unchanging
matter doesn’t exist, since this merely means that we started out with
a demand that nature cannot fulfil. Unfortunately Eddington doesn’t
discuss what alternative demand we might now make in order to build
up a more satisfactory system of scientific ideas. But in spite of his
enthusiastic support of Einstein’s theory, with its implicit assumption
of reversibility, Eddington hesitates at least once in his advocacy
of reversible laws, for facts are turning up which suggest that this
undiscussed presupposition may not prove valid.[3]
Meantime Whitehead has been at work on the other side, and by
sharpening his logic till few can understand him has made the idea of
temporal process the basis of all intellectual and scientific thought,
whereas up to now process has always presented many difficult problems
for the intellect. He proposes that since the conception of matter
has been found to be unsatisfactory we must start from the basic idea
of process in building up a new physical theory. As a consequence of
his line of thought, Whitehead found it necessary to reject some of
Einstein’s arguments and to show that Einstein’s law could be reached
from quite different postulates. For instance, Whitehead assumed that
the motion of light was irreversible, and that light did not travel
with the same velocity in the two opposed directions.
So much for one aspect of the conflict, its logical and philosophical
basis. But the issue must be decided by appeal to experimental
confirmation over the widest range of phenomena. Orthodox physics still
assumes reversibility, and has on its side the explicit statement made
by Einstein in 1925,[4] but by doing so it excludes at the start any
reference to organic processes. Conceptions based on this assumption
could never be legitimately applied to life, and all attempts made
hitherto to explain the central controlling processes of organisms in
terms of classical physics have necessarily failed. We know now that
this failure could have been foreseen.
The same objection cannot be made against the basic ideas of Bergson
and Whitehead, nor against the new atomic physics as interpreted by
Born, as we shall see in a moment. To Bergson and Whitehead, as to many
others amongst whom Lloyd Morgan must be mentioned, the process of
nature is creative, i.e. it involves the coming into being of the new,
the appearance of new combinations essentially precluded before. This
probably means that the laws of physics which are to describe what is
actually happening in the world must be given irreversible form. For
reversible equations make no distinction between to-day and to-morrow,
and cannot express the fact that at later moments new forms may emerge,
either in the evolution of organisms or of stars. On the other hand
irreversible laws can be arranged so as to display time as an active
factor in causation, i.e. to emphasize the fact that a certain period
of time necessarily has to pass before some new combination can be
attained.[5]
The upholders of a real process in nature can appeal to the facts of
organic life, human memory, and to biological and stellar evolution.
But their case is still weak because fundamental irreversibility
has not yet received explicit mathematical formulation suitable for
experimental test. When this has been done the intellectual battle will
be brought to its decision, and if irreversibility wins the day biology
and psychology will find themselves in possession of a physical basis
well suited to the facts with which they have to deal.
There is reason to believe that the decision will be made very soon.
We saw that the implicit assumption of reversibility underlies all
Newtonian conceptions. It may therefore be that the reason why we
cannot interpret atomic behaviour in terms of particle motions is that
electrical and radiational processes are essentially irreversible.
Particle motion and wave propagation--the two ideas on which all
modern theories of matter are based--are both represented by
mathematical expressions which are essentially reversible since time
enters only through the square of ‘dt’. If the quantum processes should
prove to be irreversible, we have already found a reason why the old
conceptions of particles and waves must be inadequate.
This speculation may indeed be found correct, since Born, one of
the leading experts in Quantum Dynamics, asserts that all quantum
processes are irreversible and that the apparent reversibility of
classical processes is only an approximation due to the fact that their
irreversibility happens to be negligible.[4] We may therefore hope that
the atomic physicists will soon formulate the quantum laws in a clearly
irreversible form which admits of precise experimental test.
But this may take some years, and in the meantime we must look around
and see how this issue is affecting current thought. We find the doubt
about process presented by Mr Sullivan (in _Gallio_), who has not yet
made up his mind to which side science will grant the victory. Thus on
one page he writes: “it seems to be true that events do not really take
place, we come across them” and suggests that process may be “a totally
irrelevant idea when applied to reality”. But later we learn to our
surprise that “it seems likely that (in scientific theory) the world
will have to be regarded as an evolutionary process, where patterns of
value emerge”. However, this inconsistency need not bother us, since
we are told that “the teachings of science so far as the spiritual
problems of man are concerned are merely irrelevant”.
These views reflect perfectly the uncertainty of the time, and will be
looked back on as a precious record of the state of mind which preceded
the scientific synthesis. Perhaps the most interesting feature of
the essay is the indecision it displays with regard to the spiritual
importance of science. This is a relic from the days when there were
two worlds, the world of science and the world of religion and art. No
one ever knew which of these worlds they were living in, and this is no
wonder. For the division was made only because at one time it looked
as though the scientific method could only deal with _quantities_,
and therefore that science could have nothing to say about values or
qualities. This view is no longer tenable. For instance, there is a
quality in organic integration which most of us value, and without this
and many other such conceptions biology and psychology could not get
far.
Before proceeding any further it is necessary to correct a common
misunderstanding with regard to the significance of Einstein’s theory
of relativity. This theory is mathematical, and is based on a series
of postulates which rule out any claim to present an ultimate theory
of space and time. One of these postulates[6] asserts that all our
physical knowledge can be reduced to the space-time coincidences
of pairs of point-events, or in other words the intersection of
the world-lines of electrons. No respect for the supreme genius
who predicted two experimental results and eliminated the chief
discrepancies remaining in Newtonian theory should restrain scientists
from pointing out that this postulate assumes something that has never
been known to occur, and has no valuable reference to the world of
physical experiment. The confirmation of Einstein’s final equations
cannot give any validity to this postulate. For it is difficult to
think of any physical experience considered by theoretical physics
which does not involve the perception of light or colour, and one
cannot assume that the perception of light is a perception of
coincidences. Light varies in colour and intensity; coincidence in
space is too abstract to account for an effect which is subject to
variation. Moreover all physical experience requires a certain amount
of time, and this fact is neglected if perception is reduced to the
recognition of instantaneous coincidences. Even if these two criticisms
are left on one side we still have to notice that Einstein’s postulate
rules out from the range of physics the important fact that many
processes are irreversible. For instance, if we accept Einstein’s
definition of physical experience, then the interesting fact that
radioactivity is only observed in the form of disintegration, and not
also as the reverse process of a spontaneous building up of heavier
elements from lighter, has to be left over by physics to be dealt with
by some other science.
It almost always happens that the formulations of genius are
exaggerated and form the basis of a pernicious orthodoxy, and it has
certainly happened to relativity theory. Against a tide of exaggerated
praise Whitehead, Larmor, and Bridgman, as well as some Continental
astronomers, have debated the general assumption that the theory of
relativity is adequate to its task, but those in whose hands the power
of orthodoxy lies have not yet answered their criticisms in print.
Neglect has always been the weapon by which orthodoxy has unknowingly
hindered the advance of new ideas. But while this neglect is easy to
understand, it is really remarkable that the postulates of relativity
theory were not subjected to closer examination before it was made the
basis of wide philosophical speculation. The experimental confirmation
of Einstein’s law of gravitation does not guarantee his postulates,
since Whitehead has reached a similar law (identical within the
accuracy of the observations) from different assumptions.
Einstein’s profound creative intuition and use of a difficult
technique compel our deepest respect, but his work should never have
been regarded as a _general_ theory of time and space. Not only does
he neglect the question of irreversibility but it is very doubtful if
periodic processes can be made to fit into his scheme, as has been
pointed out by Russell and Bridgman during the last year. Probably
Einstein himself has never regarded his theory as more than a stage in
the attempt to create a still wider physical synthesis, and we must
not interpret in a broad sense his statement that one of the demands
of his theory “takes away from space and time the last remnant of
physical objectivity”.[6] This could only be true if physical time
shared the absolute symmetry of space, i.e. if physical processes
were all reversible. But there are processes from which we can obtain
an objective criterion of the direction of time, and hence time does
retain an element of physical objectivity as distinct from the
absolute symmetry of space. One of the most interesting features in the
future of physics will be the explanation of the fact that Einstein
reached a correct law from postulates of limited validity, and in
this connection Whitehead’s alternative derivation may prove to be of
importance.