|C. D. Broad, Scientific Thought, 1923|
The present book is ultimately based on a course of lectures delivered to the third year students of science at the University of Bristol in the session 1920-21. It is an admirable custom, which, like many other benefits, that University owes to my distinguished predecessor, Professor Lloyd Morgan, that all students of science are expected to attend such a course before completing their career. It seemed worth while to elaborate the lectures, to remove their more obvious blemishes, and to present them to a wider public.
In the First Part I have started with the highly sophisticated concepts of the classical mathematical physics, have tried to express them clearly, and have then discussed the modifications which recent advances in scientific knowledge have necessitated in these concepts. I have carried this account to the end of the Second Theory of Relativity. I have not penetrated into the still more revolutionary speculations of Weyl, because I do not feel that I yet understand them well enough myself to venture to explain them to others. A philosopher who regards ignorance of a scientific theory as a sufficient reason for not writing about it cannot be accused of complete lack of originality as a study of recent philosophical literature will amply prove.
I begin with an Introduction, which states what I think Philosophy to be about, and how I think it to be connected with the special sciences. I then try to explain in simple terms the nature and objects of Whitehead's Principle of Extensive Absttaction. This seems to me to be the "Prolegomena to every future Philosophy of Nature." It is quite possible to explain its motives and general character without entering deeply into those logico-mathematical complications which are inevitable when it is applied in detail. Next, greatly daring I have discussed the difficult problems which centre upon the general notion of Time and Change. Here I have tried to make some answer to the very disturbing arguments by which Dr M'Taggart has claimed to disprove the reality of these apparently fundamental features of the Universe. After this the rest of the First Part should be fairly plain sailing to anyone of decent general education, though I do not pretend that it can be understood without effort by persons who are unfamiliar with the subjects which it treats.
In some of these later chapters the reader will find a number of mathematical formulae. He must not be frightened of them, for I can assure him that they involve no algebraical processes more advanced than the simple equations which he learnt to solve at his mother's knee. I myself can make no claims to be a mathematician: the most I can say is that I can generally follow a mathematical argument if I take enough time over it. I like to believe that, in expounding the Theory of Relativity, a clumsy mathematician has some of the qualities of his defects. His own former difficulties will at least suggest to him the places where others are likely to have trouble.
In Part II we start afresh at a quite different level. Here I try to point out the sensible and perceptible facts which underlie the highly abstract concepts of science, and the cruder, but still highly sophisticated, concepts of common-sense. Beside the intrinsic interest and importance of this topic it has a direct bearing on Part I. A great deal of the difficulty which many people have in accepting the newer views of Space, Time and Motion, arises from the fact that they regard the traditional concepts as perfectly plain and obvious, whilst they feel that the later modifications are paradoxes, forced on them vi et armis by a few inconvenient and relatively trivial facts. The moment we recognise how extraordinarily remote the classical concepts are from the crude facts of sense-experience, from which they must have been gradually elaborated, this source of incredulity vanishes. The hold of the tradition is loosened; and we are prepared to consider alternative, and possibly more satisfactory, conceptual syntheses of sensible facts.
I have tried in Part II to focus before my mind what seems to me to be the most important work that has been done on these subjects since 1914, when the publication of my Perception, Physics, and Reality unhappilv precipitated a European war. If I have learnt nothing else since then, I have at least come to see the extreme complexity of the problem of the external world and of our supposed knowledge of it. My obligations to Moore, Russell, Whitehead and Stout are continual, and will be perfectly obvious to anyone acquainted with the literature of the subject. I here make my grateful acknowledgments to them, once for all. To a less extent I have been influenced by Alexander and Dawes Hicks. I have merely mentioned Dawes Hicks's theory of appearance and then left it. This is not because I think it either impossible or unimportant, but because I am here deliberately trying to work out a different view, which I also think to be possible and important.
I cannot claim to have put forward any new and startling theory of the universe. If I have any kind of philosophical merit, it is neither the constructive fertility of an Alexander, nor the penetrating critical acumen of a Moore; still less is it that extraordinary combination of both with technical mathematical skill which characterises Whitehead and Russell. I can at most claim the humbler (yet useful) power of stating difficult things clearly and not too superficially.
"Excudent alii spirantia mollius aera
Credo equidem; vivos ducent de marmore vultus;"
but I hope that I may at least have smolten some of the metal and hewn some of the stone which others will use in their constructions.
I must end by thanking Dr R. S. Paton of Perth for kindly reading the proofs and helping me with the index; Mr E. Harrison, of Trinity College, Cambridge, for his gallant efforts to involve my dedication in "the decent obscurity of a learned language"; and the printers for the care which they have taken in printing what must have been a rather troublesome piece of work.
C. D. BROAD.
Contents -- Go to the Introduction