sfied
about this question. He pointed out a difficulty which a mere belief
in empirical continuity does not solve. Why do we believe more
confidently in some uniformities than in others? Why would a reported
breach of one be regarded with more incredulity than that of another?
Suppose a traveller to return from a strange country and report that
he had met men with heads growing beneath their shoulders, why would
this be pronounced more incredible than a report that he had seen a
grey crow? All crows hitherto observed have been black, and in all men
hitherto observed the heads have been above the shoulders: if the
mere continuity of observed uniformities is all that we go upon in
our inferences, a breach of the one uniformity should be just as
improbable as a breach of the other, neither more nor less. Mill
admitted the difficulty, and remarked that whoever could solve it
would have solved the problem of Induction. Now it seems to me that
this particular difficulty may be solved, and yet leave another
behind. It may be solved within the limits of the principle of
emperical--meaning by that observational--continuity. The uniform
blackness of the crow is an exception within a wider uniformity: the
colour of animals is generally variable. Hence we are not so much
surprised at the reported appearance of a grey crow: it is in
accordance with the more general law. On the other hand, the uniform
position of the head relative to other parts of the body is a
uniformity as wide as the animal kingdom: it is a coincidence repeated
as often as animals have been repeated, and merely on the principle
that uniformities continue, it has an absolutely uncontradicted series
in its favour.

But is this principle really all that we assume? Do we not also assume
that behind the observed fact uniformity, there is a cause for it, a
cause that does not appear on the surface of the observation, but
must be sought outside of its range? And do not the various degrees
of confidence with which we expect a repetition of the coincidence,
depend upon the extent of our knowledge of the producing causes and
the mode of their operation? At bottom our belief in the continuance
of the observed uniformities rests on a belief in the continuance of
the producing causes, and till we know what these are our belief has
an inferior warrant: there is less reason for our confidence.

To go back to the illustrations with which we started. If we have met
a man every