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

50 INTRODUCTION TO MATHEMATICS
thus conceived in this abstract way throughout the study of mathematical physics, where
only the positions and shapes of things are
considered together with their changes, is that
the events of such an abstract world are sufficient to "explain" our sensations. When we
hear a sound, the molecules of the air have
been agitated in a certain way: given the
agitation, or air-waves as they are called, all
normal people hear sound; and if there are
no air-waves, there is no sound. And, similarly, a physical cause or origin, or parallel
event (according as different people might
like to phrase it), underlies our other sensations. Our very thoughts appear to correspond to conformations and motions of the
brain; injure the brain and you injure the
thoughts. Meanwhile the events of this physical universe succeed each other according to
the mathematical laws which ignore all special
sensations and thoughts and emotions.
Now, undoubtedly, this is the general
aspect of the relation of the world of mathematical physics to our emotions, sensations,
and thoughts; and a great deal of controversy has been occasioned by it and much ink
spilled. We need only make one remark.
The whole situation has arisen, as we have
seen, from the endeavour to describe an external world "explanatory" of our various
individual sensations and emotions, but a