lar uniformities of which it is made up. * * *

"With respect to the general law of causation, it does
appear that there must have been a time when the
universal prevalence of that law throughout nature could
not have been affirmed in the same confident and
unqualified manner as at present. There was a time when
many of the phenomena of nature must have appeared
altogether capricious and irregular, not governed by any
laws, nor steadily consequent upon any causes. Such
phenomena, indeed, were commonly, in that early stage of
human knowledge, ascribed to the direct intervention of
the will of some supernatural being, and therefore still
to a cause. This shows the strong tendency of the human
mind to ascribe every phenomenon to some cause or other;
but it shows also that experience had not, at that time,
pointed out any regular order in the occurrence of those
particular phenomena, nor proved them to be, as we now
know that they are, dependent upon prior phenomena as
their proximate causes. There have been sects of
philosophers who have admitted what they termed Chance
as one of the agents in the order of nature by which
certain classes of events were entirely regulated; which
could only mean that those events did not occur in any
fixed order, or depend upon uniform laws of causation.
* * *

"The progress of experience, therefore, has dissipated
the doubt which must have rested upon the universality
of the law of causation, while there were phenomena
which seemed to be _sui generis_; not subject to the
same laws with any other class of phenomena, and not as
yet ascertained to have peculiar laws of their own. This
great generalisation, however, might reasonably have
been, as it in fact was by all great thinkers, acted
upon as a probability of the highest order, before there
were sufficient grounds for receiving it as a certainty.
For, whatever has been found true in innumerable
instances, and never found to be false after due
examination in any, we are safe in acting upon as
universal provisionally, until an undoubted exception
appears; provided the nature of the case be such that a
real exception could scarcely have escaped our notice.
When every phenomenon that we ever knew sufficiently
well to be able to answer the question, had a cause on
whi