has an immense amount of prima facie probability: that it is the only
means at present within reach of reducing the chaos of observed facts
to order; and lastly, that it is the most powerful instrument of
investigation which has been presented to naturalists since the
invention of the natural system of classification, and the commencement
of the systematic study of embryology.

But even leaving Mr. Darwin's views aside, the whole analogy of natural
operations furnishes so complete and crushing an argument against the
intervention of any but what are termed secondary causes, in the
production of all the phenomena of the universe; that, in view of the
intimate relations between Man and the rest of the living world, and
between the forces exerted by the latter and all other forces, I can
see no excuse for doubting that all are co-ordinated terms of Nature's
great progression, from the formless to the formed--from the inorganic
to the organic--from blind force to conscious intellect and will.

Science has fulfilled her function when she has ascertained and
enunciated truth; and were these pages addressed to men of science
only, I should now close this essay, knowing that my colleagues have
learned to respect nothing but evidence, and to believe that their
highest duty lies in submitting to it, however it may jar against their
inclinations.

But desiring, as I do, to reach the wider circle of the intelligent
public, it would be unworthy cowardice were I to ignore the repugnance
with which the majority of my readers are likely to meet the
conclusions to which the most careful and conscientious study I have
been able to give to this matter, has led me.