itself the conviction that the part of science occupied with the
actions of force in nature can properly be treated with purely
kinematic concepts. It is the fact itself which concerns us here. In
respect of it, note as a characteristic of modern text-books that they
often simply use the term 'kinetics' (a shortening of kinematics) to
designate the science of 'dynamics'.4

In the course of our investigations we shall discover the peculiarity
in human nature which - during the first phase, now ended, of man's
struggle towards scientific awareness - has caused this renunciation of
all sense-experiences except those which come to man through the sight
of a single colour-blind eye. It will then also become clear out of
what historic necessity this self-restriction of scientific inquiry
arose. The acknowledgment of this necessity, however, must not prevent
us from recognizing the fact that, as a result of this restriction,
modern scientific research, which has penetrated far into the dynamic
substrata of nature, finds itself in the peculiar situation that it is
not at all guided by its own concepts, but by the very forces it tries
to detect. And in this fact lies the root of the danger which besets
the present age.5

He who recognizes this, therefore, feels impelled to look for a way
which leads beyond a one-eyed, colour-blind conception of the world. It
is the aim of this book to show that such a way exists and how it can
be followed. Proof will thereby be given that along this way not only
is a true understanding achieved of the forces already known to science
(though not really understood by it), but also that other forces, just
as active in nature as for example electricity and magnetism, come
within reach of scientific observation and understanding. And it will
be shown that these other forces are of a kind that requires to be