er. But when this conception and name is transferred by
analogy to physical uniformities of action, an event which conforms to
the observed law or regularity of sequence, is not really caused by the
law unless we suppose that law to be representative of something
equivalent to a fixed will from which it originates. Yet we say loosely,
such an event happens _in consequence of_ the law of attraction; meaning
only, _in conformity with_ the law, so as to verify the law, to follow
from it logically. Thus again the law comes to be mistaken for an
effectual power of some kind, whereas it is merely a sort of regularity
that might result either from an intelligent will or from something
equivalent. But in thus adroitly slipping-in the conception of a
governing force or tendency, or even in openly asserting it, with
Schopenhauer or Hartmann, and in explaining the graduated resemblances
of species by the origin of one from the other, and in extending this
mode of Evolution in all directions from the known to the unknown so as
to make it pervade the universe, we at once cease to be faithful
positivists and, becoming philosophers, must submit to philosophic
criticism, since these problems cannot be settled merely by an appeal to
facts. Thus when Professor Mivart speaks of Evolution as "the continuous
progress of the material universe by the unfolding of latent
potentialities in harmony with a preordained end," the latent
potentialities, the preordained end, the procession of one species from
another, the extension of this law to every difference of time and
place--all are matters of hypothesis or intuition; but by no means of
exterior observation.

The most that observation gives us is the very imperfect suggestion of
the track that such a movement would have left behind it, not unlike the
scraps that boys litter along the road in a paper-chase. Similarly, if
in the case of organic Evolution we deny all latent potentialities and
preordained ends and throw the whole burden on accidental variations and
natural selection; if we regard the whole process as no more intelligent
or designed than that by which water seeks and finds its own level; yet
as in the case of water we must perforce introduce "a gravitating
tendency," so in the case of living organisms a "persisting" or
"struggling tendency," as an hypothesis to give unity to our facts or to
account for their uniformity. But these tendencies are as little matter
of observation as th