ARCHIMEDES
OR
THE FUTURE OF PHYSICS
TO-DAY AND TO-MORROW
_For a full list of this Series see the end
of this Book_
ARCHIMEDES
OR
THE FUTURE OF PHYSICS
BY
L. L. WHYTE
LONDON:
KEGAN PAUL, TRENCH, TRUBNER & CO., LTD.
NEW YORK: E. P. DUTTON & CO.
To
LOTTE
Made and Printed in Great Britain by
M. F. Robinson & Co. Ltd. at the Library Press, Lowestoft
CONTENTS
CHAP. PAGE
I THE SCIENCES CONVERGE 7
II A MODERN DUEL: EINSTEIN AND EDDINGTON _v._ BERGSON AND
WHITEHEAD 22
III TIME IN ASTRONOMY AND PHYSICS 37
IV AN EVOLUTIONARY EXPERIMENT 47
V PHYSICS AND THE HUMAN MIND 66
VI THE FUTURE OF THE SCIENCES 79
NOTES 95
ARCHIMEDES
OR
THE FUTURE OF PHYSICS
CHAPTER I
_The Sciences Converge_
One of the most fascinating features in the history of thought is that
on several occasions an important new idea has come simultaneously to
independent minds. Thus after Euclid’s geometry had remained without
a rival for two thousand years the conception of an alternative
non-Euclidean system was reached separately by Gauss, Lobatschewsky,
and Bolyai during the years 1820-30. Bolyai’s father, while ignorant of
the fact that Gauss had already made the same discoveries, wrote to his
son urging him to publish his results and used the following prophetic
words:
“There is some truth in this, that many things have an epoch, in which
they are found at the same time in several places, just as the violets
appear on every side in the spring.”
Another example of the simultaneous emergence of an idea in the minds
of different thinkers is given by Darwin in his introduction to the
_Origin of Species_. He there calls attention to the fact that in
1794-5 the broad idea of the evolution of species--though not its
cause--was simultaneously formulated by Goethe in Germany, St Hilaire
in France, and his own grandfather, Dr Darwin, in England. Moreover
Darwin himself had the remarkable experience of finding in an essay
submitted to him in 1858 by A. R. Wallace a complete summary of his
own unpublished theory of natural selection as the chief cause of the
evolution of species.
The last few years constitute another critical period of a similar
kind, since an idea, which when made precise will transform scientific
thought, has already come independently to many thinkers. Since 1922
many scientists have felt that in studying the emission and absorption
of light physics has come near to the problem of life.[1] Others have
proposed that in order to straighten out its atomic problems physics
will have to take a hint from biology, but what this hint should be
has not yet been indicated. The following pages suggest a definite
line of advance for physics, and interpret these isolated flashes of
intuition as evidence of a special feature in the present situation of
the sciences.
We stand at the eve of a new epoch. Physics, biology, and psychology
are converging towards a scientific synthesis of unprecedented
importance, whose influence on thought and social custom will be so
profound that it will mark a stage in human evolution. For centuries
science has concentrated its highest genius on the study of inanimate
matter; to-day the three great sciences are at last reaching the
problem of life. For their researches on matter, life, and mind are
now overlapping at one common issue: the nature of the fundamental
electrical processes which underlie radiation and chemical combination.
Thus physics is at present occupied with the changes that occur when
an atom emits either light or electricity. Biology is at the same
problem in studying the electrical processes which are the basis of all
organic behaviour, whether in primitive forms of protoplasm or in the
highly developed central nervous system of man. Meantime psychology is
dealing with an identical process when it analyses the structure of
mind, and considers the elementary changes of consciousness which are
produced when light of a given colour falls on the retina and sends
its influence to the brain.
As the result of these convergent researches, life and consciousness
will soon be subject to the first stages of a theoretically-grounded
control, compared with which the present tentative efforts of medicine
and psychology will be looked back on much as we remember the haphazard
work of the alchemists before the foundation of chemistry. But this
development of human knowledge and powers will carry with it great
responsibilities, and scientists have to prepare themselves for the new
tasks that will very soon fall to them. By indicating the main ideas
through which this broad scientific synthesis may come about, this
essay aims at showing that this possibility has to be taken seriously.
We shall first examine the situation in physics and then turn to
consider the influence which future developments of physical theory
may have on biology and psychology.
Two main types of process defy interpretation within the present scheme
of physical conceptions: life itself, and the atomic processes of
radiation and the building up of stable compounds. In organic processes
on the one hand, and the energy-interchanges of atoms on the other
hand, we find something happening which cannot adequately be explained
as a change in the _structure_ of the system considered. By structure
is meant a spatial pattern of particles, which are supposed to be
permanent and to move about like cricket balls or planets. Systems
with a structure of this kind could not display the purposive quality
of organic behaviour, and when we try to make a structural model
of the atom we find that it fails to explain why the atom radiates
energy in the abrupt packets which are called ‘quanta’, instead of
in a continuous wave. We shall return presently to the question of
organisms, after making an endeavour to discover why the atom cannot be
described in terms of a particle structure.
In 1911 Rutherford achieved remarkable success in accounting for the
results of his own researches in radioactivity by adopting a model of
the atom as a miniature solar system, with planetary electrons rotating
rapidly around a nucleus. But in order to explain the fact that the
spectrum of the light emitted by an atom shows a characteristic series
of lines, Bohr suggested that an electron inside an atom could emit
light only by making a discontinuous jump from one possible orbit to
another quite distinct orbit. This apparent discontinuity in the motion
of electrons has intrigued physicists for more than ten years, and the
following interpretations have recently been offered for this puzzling
behaviour:
1. Nature is made up of electrons, but neither space nor time is
fundamentally discontinuous. The electron appears to have some freedom
of choice, and to be able to reappear unexpectedly at forbidden places.
2. Nature is not discontinuous or arbitrary, but nevertheless
something prevents us determining all the things we should like to
know about an electron. For instance, if we try to determine exactly
where it is, it behaves so that we cannot simultaneously measure its
exact velocity. (Heisenberg.) This view may perhaps be interpreted
to mean that we have made the atom model more complex than the atom
itself is, and that consequently we have been using more quantities
than are necessary for describing all we can observe of its behaviour.
3. Nature is not made up of electrons, but of waves. The atom must be
considered as a system of electric waves spread over its whole volume.
‘Electrons’ are merely an inaccurate way of describing some of the
properties of these waves. The wave picture of the atom is, however,
to be considered only as a temporary expedient to be used until some
better description of the atom can be invented, in which both the wave
and the corpuscular properties of atoms will appear as aspects of some
more profound physical property. (Schrödinger.)
The first alternative is a mere cry of despair, since it does not
propose any line of advance. But the other two suggestions may be
combined thus:
4. The view of the atom as a structure of Newtonian particles is wrong
since it gives rise to discontinuities, and provides more quantities
than we at present need. A new formulation of atomic processes must
be found using fewer quantities which will explain why we find wave
properties, and why sometimes the electron does behave like a small
billiard ball though really it is some different sort of thing.
Now since the Newtonian mathematics of moving particles is inadequate
for describing the changes that go on in the atom--just as it is for
describing organic processes--there must be some assumption implicit in
Newton’s laws which is valid neither for atom nor for organism. Such
an assumption can be found very easily, though physics has never given
it much attention. It is that the elementary processes in nature are
_reversible_, or would be if they could be isolated. By reversible is
here meant that the laws governing the process remain unchanged when
the direction of time is reversed, i.e. when -t is substituted for +t.
If the law is changed by this substitution so that the reversed process
never occurs or is recognizably different, then the process is called
irreversible. An irreversible process can therefore be used to yield an
objective criterion of past and future, when these terms have been once
defined.
To take an example. If I am standing behind a hedge and take a
cinematograph film of a stone which suddenly rises in the air and
disappears from sight, I could not tell from an examination of the
film which way to wind it. Thus if it is wound one way the stone
appears to rise, and if wound the other way to fall from the sky.
To tell which was the right way I should have to use my subjective
sense of the direction of time, i.e. remember the fact that I saw the
stone low in the air before I saw it high up. This case, like every
gravitational process, is reversible, and motions of this kind have
provided the basis for modern physical conceptions.
But suppose that instead I had taken a film of a cup of tea as it was
cooling. One end of the film would show the steam above the cup and the
spoon changing in length as it changed in temperature. Passing along
the film these effects would grow less marked until the successive
photos showed no variation when the temperature of the tea was nearly
that of the surrounding air. It would be obvious which way to wind
this film, without using any subjective criterion supplied from memory
of the individual process which had been photographed. This process is
irreversible, but physics has hitherto assumed that all such processes
are merely the statistical result of a chaos of molecular motions each
of them perfectly reversible.
The assumption of reversibility seems to some physicists so fundamental
that they think there could be no science without it. But that is
a mere prejudice arising from the fact that Newton conceived one
particular way of giving mathematical formulation to the measurable
features of physical processes. By suggesting that all the laws of
nature might take a form similar to his law of gravitation, he made
the implicit assumption that all elementary processes were reversible.
Gravitational motions are so, at any rate within the accuracy of
Newton’s law, and as a consequence of the confirmation of his law
and the fact that it has been taken as a model for the whole system
of modern physical conceptions, the latter are only appropriate for
reversible processes.
Apparent irreversibility, such as the cooling of a cup of tea,
is attributed to statistical effects, and the second law of
thermodynamics, which asserts that temperatures tend to uniformity,
is treated as merely a statement of what is highly probable. This is
probably quite legitimate, but even where no statistical effect can
enter and the process is clearly irreversible physics usually adopts
any measure rather than assume that a fundamental elementary process
is irreversible.[2] We cannot be surprised at this, since if physics
once admitted that any elementary process was irreversible it would
have to give up the whole system of Newtonian conceptions. Matter,
force, energy, action, and wave properties are all unsuitable for the
treatment of irreversible effects since they all ultimately depend on
Newton’s reversible law.
An entirely new set of ideas is necessary for describing processes
which necessarily proceed in one direction, so that one particular
state of the system must precede another state. It appears conceivable
that an alternative set of conceptions to replace the Newtonian might
be established by demanding the irreversibility of all natural laws, as
well as the demands hitherto made by physics, i.e. the permanence of
matter and the conservation of energy.
The question of the reversibility of natural processes provides the key
to a great intellectual struggle which is now in progress behind the
complexities of philosophic and scientific thought. The issue can be
formulated thus:
Is there a real temporal process in nature? Is the passage of
irreversible time a necessary element in any view of the structure of
nature? Or, alternatively, is the subjective experience of time a
mere illusion in the mind which cannot be given objective expression?
These are not metaphysical questions that can still be neglected
by science with impunity. For just as Einstein made his advance by
analysing conceptions such as simultaneity, which had been thought
to be adequately understood for the purposes of empirical science,
so the next development of physical theory will probably be made by
carrying on the analysis of time from the point at which Einstein left
it. Moreover, the above questions may be put into precise scientific
form by asking if the causal relations which are studied by science
are symmetrical and reversible so that we cannot obtain from them any
criterion by which to distinguish past and future. If, on the other
hand, they are asymmetrical and irreversible, the laws of nature lead
us on necessarily from what went before to what comes afterwards.