Two Tables The following is an edited excerpt from the
introduction to a famous series of lectures (the Gifford
Lectures) the physicist Arthur Eddington gave at the University of Edinburgh 1927. The lectures
and this introduction were published a year later
in The Nature of the Physical World (1928). I have settled down to the task of writing
these lectures and have drawn up my chairs to my two
tables. Two tables! Yes; there are duplicates of every object about me - two tables, two
chairs, two pens.
This is not a very profound beginning to a course which ought to reach transcendent levels
of scientific philosophy. But we cannot touch
bedrock immediately; we must scratch a bit at the surface
of things first. And whenever I begin to scratch the first thing I strike is my two tables.
One of them has been familiar to me from earliest years. It is a commonplace object of that
environment which I call the world. How shall I describe it? It has extension;
it is comparatively permanent; it is colored; above all it is
substantial By substantial I do not merely mean that it does not collapse when I lean
upon it; I mean that it is constituted of "substance" and
by that word I am trying to convey to you some conception
of its intrinsic nature. It is a thing; not like space, which is a
mere negation; nor like time, which is - Heaven knows what!
But that will not help you to my meaning because it is the distinctive characteristic of a
"thing" to have this substantiality, and I do not think
substantiality can be described better than by saying that
it is an ordinary table. And so we go round in circles. After all if you are a plain commonsense
man, not too much worried with science, you will
be confident that you understand the nature of an
ordinary table. Table No. 2 is my scientific table. It is
a more recent acquaintance and I do not feel so familiar with
it. It does not belong to the world previously mentioned, that world which spontaneously
appears around me when I open my eyes.
It is part of a world which has forced itself on my attention. My scientific table is mostly
emptiness. Sparsely scattered in that emptiness are numerous
electric charges rushing about with great speed;
but their combined bulk amounts to less than a billionth of the bulk of the table itself.
Notwithstanding its strange construction it turns out to be an entirely efficient table.
It supports my writing paper as satisfactorily as table No.
1; for when I lay the paper on it the little electric particles
with their headlong speed keep on hitting the underside, so that the paper is maintained
in a pingpong like fashion at a nearly steady level. If
I lean upon this table I shall not go through; or, to be
strictly accurate, the chance of my elbow going through my scientific table is so excessively
small that it can be neglected.
Reviewing their properties one by one, there seems to be nothing to choose between the
two tables for ordinary purposes; but when abnormal circumstances
come about, then my scientific table shows itself superior. If the house catches fire
my scientific table will dissolve quite naturally into scientific
smoke, whereas my familiar table undergoes a metamorphosis of substance which I can only
regard as miraculous.
There is nothing substantial about my second table. It is nearly all empty space - space
pervaded, it is true, by fields of force, but these are assigned
to the category of "influences", not of "things". Even in
the minute part which is not empty we must not assume there is substance. In dissecting
matter into electric charges we have travelled far from
the picture which first gave rise to the conception of
substance. The whole trend of modern scientific views
is to break down the separate categories of "things",
"influences", "forms", etc., and to substitute a common background of all experience. Whether
we are studying a material object, a magnetic
field, a geometrical figure, or a duration of time, our
scientific information is summed up in measures; neither the apparatus of measurement nor the
mode of using it suggests that there is anything essentially different in these problems. The
measures themselves afford no ground for a classification
by categories. We feel it necessary to concede some
background to the measures - an external world; but the attributes of this world, except in
so far as they are reflected in the measures, are outside
scientific scrutiny. Science has revolted against attaching the
exact knowledge contained in these measurements to a
traditional picture gallery of conceptions which convey no information and obtrude irrelevancies
into the scheme of knowledge. I will not here stress further the non-substantiality
of electrons, since it is scarcely necessary to the
present line of thought. Conceive them as you will, there is a vast difference between
my scientific table with its substance thinly scattered
in specks in a region mostly empty and the table of everyday
life which we regard as solid reality. It makes all the difference in the world whether
the paper before me is poised on a swarm of flies and
sustained by a series of tiny blows from the swarm underneath, or whether it is supported
because there is substance below it,; all the difference
in conception at least, but no difference to my practical
task in the lectures. Modern physics has by delicate test and remorseless
logic assured me that my second scientific table
is the only one which is really there - wherever "there" may be. On the other hand, I need
not tell you that modern physics will never succeed
in exorcising that first table - strange compound of
external nature, mental imagery and inherited prejudice-which lies visible to my eyes and
tangible to my grasp.
However, we must bid good-bye to it for the present for we are about to turn from the
familiar world to the scientific world revealed by
physics. "You speak paradoxically of two worlds. Are
they not really two aspects or two interpretations of one
and the same world?" Yes, no doubt they are ultimately to be identified
after some fashion. But the process by which the
external world of physics is transformed into a world of familiar is outside the scope of
physics. And so the world studied according to the methods
of physics remains detached from the world familiar
to consciousness. Provisionally, we regard the table which is the subject of physical
research as altogether separate from the familiar table.
It is true that the whole scientific inquiry starts from the familiar world and in the
end it must return to the familiar world; but the part of the
journey over which the physicist has charge is in foreign
territory. Until recently there was a much closer linkage;
the physicist used to borrow the raw material of his
world from the familiar world, but he does so no longer. His raw materials are electrons,
quanta, potentials, Hamiltonian functions, etc., and
he is nowadays careful to guard these from contamination by conceptions from the common
world. There is a familiar table parallel to the
scientific table, but there is no familiar electron or quantum
parallel to these scientific entities. We do not even desire to manufacture a familiar
counterpart to these things. After the physicist has quite
finished his world-building a linkage or identification is
allowed; but premature attempts at linkage have been found to be entirely mischievous.
Science aims at constructing a world which is a symbolic counterpart of the world of
commonplace experience. It is not necessary that every
individual symbol should represent something in common
experience. The man in the street making this demand for concrete explanation of the things
referred to in science will be disappointed. It is like our experience in learning to read.
That which is written in a book is symbolic of a story in
real life. The whole intention of the book is that ultimately a reader will identify
some symbol, say BREAD, with one of the conceptions of familiar
life. But it is mischievous to attempt such identifications prematurely, before the letters
are strung into words and the words into sentences. The symbol E is not the counterpart of anything
in familiar life. Letters are abstract, and sooner or
later one has to realize it. The external world of physics has thus become
a world of shadows. In removing our illusions we
have removed the substance of the world. Later perhaps we may inquire whether in our zeal
to cut out all that is unreal we may not have used
the knife too ruthlessly. Perhaps, reality is a child which
cannot survive without its nurse illusion. But if so, that is of little concern to the
scientist, who has good reasons for pursuing his investigations
in the world of shadows and is content to leave to the
philosopher the determination of its status in regard to reality.
In the world of physics we watch a shadowgraph performance of the drama of familiar life.
The shadow of my elbow rests on the shadow table
as the shadow ink flows over the shadow paper. It is
all symbolic, and as a symbol the physicist leaves it. Then comes the alchemist Mind who
transmutes the symbols. The sparsely spread nuclei of
electric force become a tangible solid; their restless
agitation becomes the warmth of summer, a gorgeous rainbow. In the transmuted world
new significances arise which are scarcely to
be traced in the world of symbols; so that it becomes a world
of beauty and purpose - and, alas, suffering and evil.
The frank realization that physical science is concerned with a world of shadows is one
of the most significant of recent advances. I do not mean
that physicists are to any extent preoccupied with the
philosophical implications of this. From their point of view it is not so much a withdrawal
as an assertion of freedom.
But I am convinced that a just appreciation of the physical world as it is understood
by science today carries with it a feeling of open-mindedness
towards a wider significance. The path of science must
be pursued for its own sake, irrespective of the views it may afford of a wider landscape;
in this spirit we must follow the path whether it leads to
the hill of vision or the tunnel of obscurity.