The Doctrine of Evolution | Page 4

being true. Karl Pearson defines science as organized knowledge, and
Huxley calls it organized common sense. These definitions mean the
same thing. They mean that in order to know anything that deserves
confidence, in order to obtain a real result, it is necessary in the first
place to establish the reality of facts and to discriminate between the
true, the not so sure, the merely possible, and the false. Having accurate
and verified data, scientific method then proceeds to classify them, and
this is the organizing of knowledge. The final process involves a
summary of the facts and their relations by some simple expression or
formula. A good illustration of a scientific principle is the natural law
of gravitation. It states simply that two bodies of matter attract one
another directly in proportion to their mass, and inversely in proportion
to the square of the distance between them. In this concise rule are
described the relations which have been actually determined for masses
of varying sizes and at different distances apart,--for snowflakes falling
to the earth, for the avalanche on the mountain slope, and for the
planets of the solar system, moving in celestial cooerdination.
Such a principle as the law of gravitation, like evolution, is true if the
basic facts are true, if they are reasonably related, and if the conclusion
is drawn reasonably from them. It is true for all persons who possess
normal minds, and this is why Huxley speaks of science as "common
sense,"--that is, something which is a reasonable and sensible part of
the mental make-up of thinking persons that they can hold in common.
The form and method of science are fully set forth by these definitions,
and the purpose also is clearly revealed. For the results of investigation
are not merely formulae which summarize experience as so much
"conceptual shorthand," as Karl Pearson puts it, but they must serve
also to describe what will probably be the orderly workings of nature as
future experience unfolds. Human endeavor based upon a knowledge of
scientific principles must be far more reliable than where it is guided by

mere intuition or unreasoned belief, which may or may not harmonize
with the everyday world laws. Just as the law of gravitation based upon
past experience provides the bridge builder and the architect with a
statement of conditions to be met, so we shall find that the principles of
evolution demonstrate the best means of meeting the circumstances of
life.
Evolution has developed, like all sciences, as the method we have
described has been employed. Alchemy became chemistry when the
so-called facts of the medievalist were scrutinized and the false were
discarded. Astrology was reorganized into astronomy when real facts
about the planets and stars were separated from the belief that human
lives were influenced by the heavenly bodies. Likewise the science of
life has undergone far-reaching changes in coming down to its present
form. All the principles of these sciences are complete only in so far as
they sum up in the best way the whole range of facts that they describe.
They cannot be final until all that can be known is known,--until the
end of all knowledge and of time. It is because he feels so sure of what
has been gained that the man of science seems to the unscientific to
claim finality for his results. He himself is the first to point out that
dogmatism is unjustified when its assertions are not so thoroughly
grounded in reasonable fact as to render their contrary unthinkable. He
seeks only for truth, realizing that new discoveries must oblige him to
amend his statement of the laws of nature with every decade. But the
great bulk of knowledge concerning life and living forms is so sure that
science asserts, with a decision often mistaken for dogmatism, that
evolution is a real natural process.
* * * * *
The conception of evolution in its turn now demands a definite
description. How are we to regard the material things of the earth? Are
they permanent and unchanged since the beginning of time, unchanging
and unchangeable at the present? We do not need Herbert Spencer's
elaborate demonstration that this is unthinkable, for we all know from
daily experience that things do change and that nothing is immutable.
Did things have a finite beginning, and have they been "made" by some

supernatural force or forces, personified or impersonal, different from
those agencies which we may see in operation at the present time? So
says the doctrine of special creation. Finally, we may ask if things have
changed as they now change under the influence of what we call the
natural laws of the present, and which if they operated in the past
would bring the world and all that is therein to