The Relations Between Religion and Science | Page 4

with these materials only on the
condition that they are reducible to invariable laws. If any observation
made by the senses is not capable of being brought under the laws
which are found to govern all other observations, it is not yet brought
under the dominion of Science. It is not yet explained, nor understood.
As far as Science is concerned, it may be called as yet non-existent. It
is for this very reason possible that the examination of it may be of the
very greatest importance. To explain what has hitherto received no
explanation constitutes the very essence of scientific progress. The
observation may be imperfect, and may at once become explicable as
soon as it is made complete; or, what is of far more value, it may be an
instance of the operation of a new law not previously known,
modifying and perhaps absorbing the law up to that time accepted.
When it was first noticed in Galileo's time that water would not ascend
in the suction pipe of a pump to a greater height than 32 feet, the old
law that nature abhors a vacuum was modified, and the reasons why
and the conditions under which Nature abhors a vacuum were
discovered. The suction of fluids was brought under the general law of
mechanical pressure. The doctrine that Nature abhorred a vacuum had

been a fair generalization and expression of the facts of this kind that
up to that time had been observed. A new fact was observed which
would not fall under the rule. The examination of this fact led to the old
rule being superseded; and Science advanced a great step at once. So in
our own day was the planet Neptune discovered by the observation of
certain facts which could not be squared with the facts previously
observed unless the Law of Gravitation was to be corrected. The result
in this case was not the discovery of a new Law but of a new Planet;
and consequently a great confirmation of the old Law. But in each case
and in every similar case the investigation of the newly observed fact
proceeds on the assumption that Nature will be found uniform, and on
no other assumption can Science proceed at all.
Now it is this assumption which must be first examined. What is its
source? What is its justification? What, if any, are its limits?
It is not an assumption that belongs to Science only. It is in some form
or other at the bottom of all our daily life. We eat our food on the
assumption that it will nourish us to-day as it nourished us yesterday.
We deal with our neighbours in the belief that we may safely trust
those now whom we have trusted and safely trusted heretofore. We
never take a journey without assuming that wood and iron will hold a
carriage together, that wheels will roll upon axles, that steam will
expand and drive the piston of an engine, that porters and stokers and
engine-drivers will do their accustomed duties. Our crops are sown in
the belief that the earth will work its usual chemistry, that heat and light
and rain will come in their turn and have their usual effects, and the
harvest will be ready for our gathering in the autumn. Look on while a
man is tried for his life before a jury. Every tittle of the evidence is
valued both by the judge and jury according to its agreement or
disagreement with what we believe to be the laws of Nature, and if a
witness asserts that something happened which, as far as we know,
never happened at any other time since the world began, we set his
evidence aside as incredible. And the prisoner is condemned if the facts
before us, interpreted on the assumption that the ordinary laws of
Nature have held their course, appear to prove his guilt.

What right have we to make such an assumption as this?
The question was first clearly put by Hume, and was handled by him
with singular lucidity; but his answer, though very near the truth, was
not so expressed as to set the question at rest.
The main relation in which the uniformity of Nature is observed is that
of cause and effect. Hume examines this and maintains that there is
absolutely nothing contained in it but the notion of invariable sequence.
Two phenomena are invariably found connected together; the prior is
spoken of as the cause, the posterior as the effect. But there is
absolutely nothing in the former to define its relation to the latter,
except that when the former is observed the latter, as far as we know,
invariably follows. A ball hits another ball of equal size, both being
free to move. There