Originally published in 1931. The present work had its beginnings in a
series of papers published jointly some years ago by Dr Dorothy Wrinch
and myself. Both before and since that time several books purporting to
give analyses of the principles of scientific inquiry have appeared, but
it seems to me that none of them gives adequate attention to the chief
guiding principle of both scientific and everyday knowledge that it is
possible to learn from experience and to make inferences from it beyond
the data directly known by sensation. Discussions from the philosophical
and logical point of view have tended to the conclusion that this
principle cannot be justified by logic alone, which is true, and have
left it at that. In discussions by physicists, on the other hand, it
hardly seems to be noticed that such a principle exists. In the present
work the principle is frankly adopted as a primitive postulate and its
consequences are developed. It is found to lead to an explanation and a
justification of the high probabilities attached in practice to simple
quantitative laws, and thereby to a recasting of the processes involved
in description. As illustrations of the actual relations of scientific
laws to experience it is shown how the sciences of mensuration and
dynamics may be developed. I have been stimulated to an interest in the
subject myself on account of the fact that in my work in the subjects of
cosmogony and geophysics it has habitually been necessary to apply
physical laws far beyond their original range of verification in both
time and distance, and the problems involved in such extrapolation have
therefore always been prominent. This is a high quality digital version
of the original title, thus a few of the images may be slightly blurred
and difficult to read.
