nces. In a very definite sense that is true. The logical
consequence of this admission should be merely the recognition that the
idea of evolution as developed in the natural sciences cannot be the
whole idea.

The entire history of anything, Spencer tells us, must include its
appearance out of the imperceptible, and its disappearance again into
the imperceptible. Be it a single object, or the whole universe, an
account which begins with it in a concrete form, or leaves off with its
concrete form, is incomplete. He uses a familiar instance, that of a
cloud appearing when vapour drifts over a cold mountain top, and again
disappearing when it emerges into warmer air. The cloud emerges from the
imperceptible as heat is dissipated. It is dissolved again as heat is
absorbed and the watery particles evaporate. Spencer esteems this an
analogue of the appearance of the universe itself, according to the
nebular hypothesis. Yet assuredly, as the cloud presupposes vapours
which had previously condensed, and the vapour clouds that had
previously evaporated, and as clouds dissolve in one place even at the
moment that they are forming in another, so we are told of nebulae which
are in every phase of advance or of decline. To ask which was first,
solid masses or nebulous haze, is much like recurring to the riddle of
the hen and the egg. Still, we are told, we have but to extend our
thought beyond this emergence and subsidence of sidereal systems, of
continents, nations, men, to find a permanent totality made up of
transient individuals in every stage of change. The physical assumption
with which Spencer sets out is that the mass of the universe and its
energy are fixed in quantity. All the phenomena of evolution are
included in the conservation of this matter and force.

Besides the criticism which was offered above, that the mere law of the
persistence of force does not initiate our series, there is a further
objection. Even within the series, once it has been started, this law of
the persistence of force is solely a quantitative law. When energy is
transformed there is an equivalence between the new form and the old. Of
the reasons for the direction evolution takes, for the permanence of
that direction once it has been taken, so that the sequence of forms is
a progression, the explication of a latent nature--of all this, the mere
law of the persistence of force gives us no explanation whatever. The
change at random from one form of