eared to be self-originated: we come to the notion of a power
the action of which is nothing more than the continuance of preceding
action. And the special characteristic of the action of this force as
thus conceived, which we may call the derivative force, is seen to be
its regularity, just as the special characteristic of the
self-originating action was its spontaneity.

As experience increases the regularity of the action of the derivative
force is more and more observable, and then arises the notion of a law
or rule regulating the action of every such force. And a perpetually
increasing number of phenomena are brought under this head, and are
shown to be, not the immediate results of self-originating action, but
the more or less remote results of derivative action governed by laws.
And even a large number of those phenomena, which specially belong to
life and living creatures, in whom alone, if anywhere, the
self-originating action is to be found, are observed to be subject to
law and therefore to be the issue not of self-originating but of
derivative action. And this observed regularity it is found possible to
trace much more widely than it is possible to trace any clear evidence
of what we understand by force. And so, at last, we frequently use the
word force as it were by anticipation, not to express the cause of the
phenomena, which indeed we do not yet know, but as a convenient
abbreviation for a large number of facts classed under one head. And
this it is which enables Hume to maintain that we mean no more by a
cause than an event which is invariably followed by another event. We
discover invariability much faster than we can discover causation; and
having discovered invariability in any given case, we presume causation
even when we cannot yet show it, and use language in accordance with
that presumption. Thus, for instance, we speak of the force of
gravitation, although we cannot yet prove that there is any such force,
and all that we know is that material particles move as if such a force
were acting on them.

As Science advances it is seen that the regularity of phenomena is far
more important to us than their causes. And the attention of all
students of Nature is fixed on that rather than on causation. And this
regularity is seen to be more and more widely pervading all phenomena of
every class, until the mind is forced to conceive the possibility that
it may be absolutely universal, and that even will it