on the labours of scientific men in past
ages. New generalisations imagined by one thinker, new crucial
experiments devised by another, new instruments of observation invented
by another,--these have been the steps by which Science has grown and
established its authority and enlarged its dominion. When or by whom the
first steps were made we have no record. No mathematician that ever
lived showed greater natural power of intellect than he, whoever he was,
who first saw that the singular contained the universal; but we know
neither his name nor his age, nor his birthplace nor his race. But after
those first steps had been taken, we know who have been the leaders in
scientific advance. And we know what they have done, and what they are
doing; and we can conjecture the direction in which further advances
will be made. And so we can trace the development of this kind of
knowledge, and in a certain and very real sense this development may be
called an evolution.

But there is this difference between the evolution of nature and the
evolution of the science of nature. The evolution of nature results in
the existence of forms which did not exist before; the evolution of
knowledge results in the perception of laws which were already in
existence.

The knowledge grows, but the things known remain. The knowledge is not
treated as if independent of the things known or believed to be known,
as a phenomenon belonging merely to the human mind, with beginnings and
laws and consequences and history of its own. And, consequently, its
having a regular growth is not used as an argument against its
substantial truth.

The Science of Mathematics, for instance, has a history; but no
mathematician will admit that the fact that it has a history affects its
claims to acceptance as truth. We may ask, how men have been brought to
believe the deductions of the higher mathematics, and we may answer our
own question by tracing the steps; but our conviction is not shaken that
these deductions are true.

And so, too, we can trace the steps by which the great generalisations
of Science have been reached, and we may show that Kepler grew out of
Copernicus, and Newton out of Kepler; but the proof that the knowledge
of one truth has been evolved out of the knowledge of another, and that
out of the knowledge of another, is not used to show that all this
Science has nothing to do with truth at all, but is only a natural
growth of human thought. Science