Discourses: Biological and Geological Essays | Page 2

falsehood were not too glaring, they would say the
same of Faraday and Helmholtz and Kelvin.

On the other hand, of the affliction caused by persons who think that
what they have picked up from popular exposition qualifies them for
discussing the great problems of science, it may be said, as the Radical
toast said of the power of the Crown in bygone days, that it "has
increased, is increasing, and ought to be diminished." The oddities of
"English as she is spoke" might be abundantly paralleled by those of
"Science as she is misunderstood" in the sermon, the novel, and the
leading article; and a collection of the grotesque travesties of scientific
conceptions, in the shape of essays on such trifles as "the Nature of
Life" and the "Origin of All Things," which reach me, from time to
time, might well be bound up with them.
The tenth essay in this volume unfortunately brought me, I will not say
into collision, but into a position of critical remonstrance with regard to
some charges of physical heterodoxy, brought by my distinguished
friend Lord Kelvin, against British Geology. As President of the
Geological Society of London at that time (1869), I thought I might
venture to plead that we were not such heretics as we seemed to be; and
that, even if we were, recantation would not affect the question of
evolution.
I am glad to see that Lord Kelvin has just reprinted his reply to my
plea,[1] and I refer the reader to it. I shall not presume to question
anything, that on such ripe consideration, Lord Kelvin has to say upon
the physical problems involved. But I may remark that no one can have
asserted more strongly than I have done, the necessity of looking to
physics and mathematics, for help in regard to the earliest history of the
globe. (See pp. 108 and 109 of this volume.)
[Footnote 1: Popular Lectures and Addresses. II. Macmillan and Co.
1894.]
And I take the opportunity of repeating the opinion, that, whether what
we call geological time has the lower limit assigned to it by Lord
Kelvin, or the higher assumed by other philosophers; whether the
germs of all living things have originated in the globe itself, or whether
they have been imported on, or in, meteorites from without, the
problem of the origin of those successive Faunae and Florae of the

earth, the existence of which is fully demonstrated by paleontology
remains exactly where it was.
For I think it will be admitted, that the germs brought to us by
meteorites, if any, were not ova of elephants, nor of crocodiles; not
cocoa-nuts nor acorns; not even eggs of shell-fish and corals; but only
those of the lowest forms of animal and vegetable life. Therefore, since
it is proved that, from a very remote epoch of geological time, the earth
has been peopled by a continual succession of the higher forms of
animals and plants, these either must have been created, or they have
arisen by evolution. And in respect of certain groups of animals, the
well- established facts of paleontology leave no rational doubt that they
arose by the latter method.
In the second place, there are no data whatever, which justify the
biologist in assigning any, even approximately definite, period of time,
either long or short, to the evolution of one species from another by the
process of variation and selection. In the ninth of the following essays,
I have taken pains to prove that the change of animals has gone on at
very different rates in different groups of living beings; that some types
have persisted with little change from the paleozoic epoch till now,
while others have changed rapidly within the limits of an epoch. In
1862 (see below p. 303, 304) in 1863 (vol. II., p. 461) and again in
1864 (ibid., p. 89-91) I argued, not as a matter of speculation, but, from
paleontological facts, the bearing of which I believe, up to that time,
had not been shown, that any adequate hypothesis of the causes of
evolution must be consistent with progression, stationariness and
retrogression, of the same type at different epochs; of different types in
the same epoch; and that Darwin's hypothesis fulfilled these conditions.
According to that hypothesis, two factors are at work, variation and
selection. Next to nothing is known of the causes of the former process;
nothing whatever of the time required for the production of a certain
amount of deviation from the existing type. And, as respects selection,
which operates by extinguishing all but a small minority of variations,
we have not the slightest means of estimating the rapidity with which it
does its work. All that we are justified in saying is that the rate at which

it takes place