An introduction to mathematics, by A. N. Whitehead.

30 INTRODUCTION TO MATHEMATICS
masses at any distance. Again, what are the
meanings of the terms employed, Force, Mass,
Distance? Take the easiest of these terms,
Distance. It seems very obvious to us to
conceive all material things as forming a
definite geometrical whole, such that the distances of the various parts are measurable in
terms of some unit length, such as a mile or
a yard. This is almost the first aspect of a
material structure which occurs to us. It is
the gradual outcome of the study of geometry
and of the theory of measurement. Even
now, in certain cases, other modes of thought
are convenient. In a mountainous country
distances are-often reckoned in hours. But
leaving distance, the other terms, Force and
Mass, are much more obscure. The exact
comprehension of the ideas which Newton
meant to convey by these words was of slow
growth, and, indeed, Newton himself was the
first man who had thoroughly mastered the
true general principles of Dynamics.
Throughout the middle ages, under the influence of Aristotle, the science was entirely
misconceived. Newton had the advantage of
coming after a series of great men, notably
Galileo, in Italy, who in the previous two
centuries had reconstructed the science and
had invented the right way of thinking about
it. He completed their work. Then, finally,
having the ideas of force, mass, and distance