I
The well-meant and industrious efforts of professional metaphysicians
to explain to men of science in what sense science is true, in what
sense it has meaning and in what its value really consists, practically
all suffer from the defect that men of science do not recognise the
subject of investigation as being science at all. It is almost true to
say that the professional philosopher is only convincing when he is
talking about the Absolute, for that is a subject with which nobody
else is concerned; but when he devotes his attention to subjects with
which other people are familiar, it often becomes possible to put
the book down before finishing it. Thus treatises on æsthetics are
usually convincing to everybody but poets, painters and musicians,
and philosophical writings on science are probably in great demand
amongst classical scholars. Nevertheless, since philosophising on these
subjects is an agreeable mental exercise, we find that some artists
are now engaged in developing an æsthetic for themselves, and some
men of science are engaged in trying to find out what science is.
In each case the work consists chiefly in making explicit processes
which are instinctive. This fact is of the greatest importance, for,
if the instinctive equipment be lacking, the results will inevitably
be unsatisfactory. There are treatises on æsthetics, for instance,
whose chief effect on the poet is to make him doubt whether the author
could tell a good poem from a bad one; this is an absolutely fatal
objection. If poets cannot recognise what they call poetry as being
the subject of the discussion, then, as a discussion of poetry, that
discussion is worthless. Practitioners, whether artists or men of
science, seldom have the inclination to uncover and dissect what is
to them an instinctive and delightful process; but it is quite easy
for them to see (or, rather, to feel) that a suggested explanation
is unsatisfactory, although they may find it wholly impossible to
give reasons for their dissatisfaction. Nevertheless, when this
dissatisfaction is due to an inability to recognise the subject-matter,
the explanation must be condemned. It is perfectly possible, for
instance, that psycho-analysis, by introducing a mother-complex, an
inferiority-complex, and two or three more, might “explain” the Ode to
a Nightingale. But if this explanation left out everything which made
poets regard that composition as a poem, it would not be a satisfactory
explanation.
We have treated this point at some length because Dr. Campbell, in
a recent valuable book on the Elements of Physics, insists that the
physics he is talking about is that of physicists. He has endeavoured
to supply a criticism of the terms used in Physics, to find what is
meant by a Law, by a Theory, what a physicist means when he says a
proposition is “true,” or that something “exists,” or that a theory has
“meaning.” Mr. Campbell is perfectly aware that all these subjects have
already been treated by the professional metaphysician, but he claims,
and we have no doubt that his claim is just, that he is speaking not
only for himself but for the great majority of scientific men when
he says that in these discussions he not only does not recognise
the subject-matter, but he does not recognise any subject-matter.
Such words as “reality” and “existence,” as they are employed by
metaphysicians, he finds productive of nothing but great discomfort and
intense mental confusion. As he unhesitatingly rejects the hypothesis
that metaphysicians are imbeciles, he thinks this confusion can be due
only to the fact that these words are used by metaphysicians in senses
quite different from those they bear to men of science. He has not
been able to explain precisely in what the difference consists, since
he has not been able to discover what meanings metaphysicians attach
to these words. Accordingly he has confined himself to explaining the
meanings these words have in science. The result is a subtle, fairly
clear, and frequently entertaining piece of analysis. He acknowledges
that his two masters have been Poincaré and Bertrand Russell, and he
shows complete familiarity with other writers of the kind. But part
of his reason for publishing the book, he tells us, is that even the
mathematical philosophers occasionally misrepresent science as the
experimental physicist knows it. That they are mathematicians and
not physicists is a little too evident in some of their conclusions.
Thus Mach’s idea that the object of science is to economise thought
is only plausible, he thinks, to a mathematician; and a fundamental
proposition that Russell and Whitehead find quite necessary to thought
Mr. Campbell does not find necessary at all. He thinks it quite likely,
also, that scientific thinking is illogical, but not therefore invalid.
The point of view, in fact, is that there are different kinds of minds
with different needs and different satisfactions, and Mr. Campbell
claims that physicists, for example, belong to a certain species and
that the science of physics is something which exists in the minds of
physicists. Therefore this book, as he insists, is not only written
by a physicist, but it is written for physicists. He is confident
that what he has to say will be found an explicit statement of their
instinctive processes, and he thinks the highest compliment that could
be paid to his book would be for physicists to say they knew it all
before.
Now it is true that nobody but a physicist could have written this
book and that nobody ignorant of physics could understand it. It may
also be true that none but a practising physicist could understand it
with the intimacy that Mr. Campbell desires. But any reader who is
not, in Mr. Campbell’s sense, half-educated (the other half consists
of science--preferably physics) will find the book not only valuable,
but delightful. The slight touch of _brusquerie_ that the
metaphysician or the equally unfortunate “half-educated” person might
attribute to Mr. Campbell from the above exposition is not in the
least that of the horny-handed son of toil, but is the half-humorous
impatience of a subtle and vigorous thinker who is by no means naïve.
There is no reason why the audience that reads Poincaré’s popular four
volumes should not also read this book, and there are many reasons why
it should. Many of the questions raised there are here developed more
fully; most of the questions, in fact, raised by the speculations of
such men as Poincaré, Russell, Mach, etc., in so far as they affect
science, are here given systematic treatment. We hope to devote a
future article to the exposition of some of Mr. Campbell’s more
interesting results; we are concerned here to indicate the nature and
scope of the book.
The present volume is in two pretty distinct parts, the first part
being concerned with the propositions of science, and the second part
with measurement. These are to be followed by Part III. on Space and
Time, Part IV. on Force, and Part V. on Energy, although, regarding
these parts, Mr. Campbell says: “I have not the remotest idea when,
if ever, they will be published.” Without anticipating a future
discussion of the more technical parts of Mr. Campbell’s work, we may
refer here, because of the general interest taken in the subject, to
the explanation he gives of the fact that while the outside world
resolutely marks off Science from Art, yet this distinction is not at
all clear to scientific men. It is difficult, for example, in studying
the life of a great man of science, to resist the conclusion that his
incentives and satisfactions are indistinguishable from those of a
great artist. Yet it seems to be undoubtedly true that a work of Art
is something personal, whereas Science is obviously impersonal. Mr.
Campbell asks us to distinguish between truth and meaning. The truth
of science is something impersonal, but its meaning is personal. The
achievement of Newton and Maxwell is as personal as that of Giotto,
Shakespeare and Bach. Their dreams were not less personal, nor less
delightful, and it is nothing to their discredit that their dreams also
came true. And the fact that the meaning of a scientific theory is
something that exists, perhaps, only for men of science, has an obvious
parallel in Art. The following passage from Mr. Campbell’s book is one
to which every man of science would give instant assent:
Nobody who has any portion of the scientific spirit can fail to
remember times when he has thrilled to a new discovery as if it were
his own. He has greeted a new theory with the passionate exclamation,
“It must be true!” He has felt that its eternal value is beyond
all reasoning, that it is to be defended, if need be, not by the
cold-blooded methods of the laboratory or the soulless processes of
formal logic, but, like the honour of a friend, by simple affirmation
and eloquent appeal. The mood will and should pass; the impersonal
enquiry must be made before the new ideas can be admitted to our
complete confidence. But in that one moment we have known the real
meaning of science, we have experienced its highest value; unless such
knowledge and such experience were possible, science would be without
meaning and therefore without truth.