ld be denied by an idealist like
Berkeley, or by a sceptic like Hume. Mr. Spencer takes another line.
With him, as with the uneducated man, there is no doubt or question as
to the existence of an external world. But he differs from the
uneducated, who think that the world really is what consciousness
represents it to be. Our states of consciousness are mere symbols of
an outside entity which produces them and determines the order of
their succession, but the real nature of which we can never know.
[Footnote: In a paper, at once popular and profound, entitled 'Recent
Progress in the Theory of Vision,' contained in the volume of lectures
by Helmholtz, published by Longmans, this symbolism of our states of
consciousness is also dwelt upon. The impressions of sense are the
mere signs of external things. In this paper Helmholtz contends
strongly against the view that the consciousness of space is inborn;
and he evidently doubts the power of the chick to pick up grains of
corn without preliminary lessons. On this point, he says, further
experiments are needed. Such experiments have been since made by Mr.
Spalding, aided, I believe, in some of his observations by the
accomplished and deeply lamented Lady Amberly; and they seem to prove
conclusively that the chick does not need a single moment's tuition to
enable it to stand, run, govern the muscles of its eyes, and peck.
Helmholtz, however, is contending against the notion of
pre-established harmony; and I am not aware of his views as to the
organisation of experiences of race or breed.] In fact, the whole
process of evolution is the manifestation of a Power absolutely
inscrutable to the intellect of man. As little in our day as in the
days of Job can man by searching find this Power out. Considered
fundamentally, then, it is by the operation of an insoluble mystery
that life on earth is evolved, species differentiated, and mind
unfolded, from their prepotent elements in the immeasurable past.

The strength of the doctrine of Evolution consists, not in an
experimental demonstration (for the subject is hardly accessible to
this mode of proof), but in its general harmony with scientific
thought. From contrast, moreover, it derives enormous relative
cogency. On the one side we have a theory (if it could with any
propriety be so called) derived, as were the theories referred to at
the beginning of this Address, not from the study of nature, but from
the observation of