scientific, partly anecdotic, which appear to me to be somewhat misleading.
We are told, to begin with, that Sir Charles Lyell's doctrine respecting
the proper mode of interpreting the facts of geology (which is commonly
called uniformitarianism) "does not hold its head quite so high as it once
did." That is great news indeed. But is it true? All I can say is that I am
aware of nothing that has happened of late that can in any way justify it;
and my opinion is, that the body of Lyell's doctrine, as laid down in that
great work, _The Principles of Geology_, whatever may have happened to its
head, is a chief and permanent constituent of the foundations of geological
science.
But this question cannot be advantageously discussed, unless we take some
pains to discriminate between the essential part of the uniformitarian
doctrine and its accessories; and it does not appear that the Duke of
Argyll has carried his studies of geological philosophy so far as this
point. For he defines uniformitarianism to be the assumption of the
"extreme slowness and perfect continuity of all geological changes."
What "perfect continuity" may mean in this definition, I am by no means
sure; but I can only imagine that it signifies the absence of any break in
the course of natural order during the millions of years, the lapse of
which is recorded by geological phenomena.
Is the Duke of Argyll prepared to say that any {272} geologist of
authority, at the present day, believes that there is the slightest
evidence of the occurrence of supernatural intervention, during the long
ages of which the monuments are preserved to us in the crust of the earth?
And if he is not, in what sense has this part of the uniformitarian
doctrine, as he defines it, lowered its pretensions to represent scientific
truth?
As to the "extreme slowness of all geological changes," it is simply a
popular error to regard that as, in any wise, a fundamental and necessary
dogma of uniformitarianism. It is extremely astonishing to me that any one
who has carefully studied Lyell's great work can have so completely failed
to appreciate its purport, which yet is "writ large" on the very
title-page: "_The Principles of Geology, being an attempt to explain the
former changes of the earth's surface by reference to causes now in
operation_." The essence of Lyell's doctrine is here written so that those
who run may read; and it has nothing to do with the quickness or slowness
of the past changes of the earth's surface; except in so far as existing
analogous changes may go on slowly, and therefore create a presumption in
favour of the slowness of past changes.
With that epigrammatic force which characterises his style, Buffon wrote,
nearly a hundred and fifty years ago, in his famous _Theorie de la Terre_:
"Pour juger de ce qui est arrive, et meme de ce qui arrivera, nous n'avons
qu'a examiner ce qui arrive." The key of the past, as of the future, is to
be sought in the present, and only when known causes of change have {273}
been shown to be insufficient have we any right to have recourse to unknown
causes. Geology is as much a historical science as archaeology; and I
apprehend that all sound historical investigation rests upon this axiom. It
underlay all Hutton's work and animated Lyell and Scrope in their
successful efforts to revolutionise the geology of half a century ago.
There is no antagonism whatever, and there never was, between the belief in
the views which had their chief and unwearied advocate in Lyell and the
belief in the occurrence of catastrophes. The first edition of Lyell's
_Principles_, published in 1830, lies before me; and a large part of the
first volume is occupied by an account of volcanic, seismic, and diluvial
catastrophes which have occurred within the historical period. Moreover,
the author, over and over again, expressly draws the attention of his
readers to the consistency of catastrophes with his doctrine.
Notwithstanding, therefore, that we have not witnessed within the last
three thousand years the devastation by deluge of a large continent,
yet, as we may predict the future occurrence of such catastrophes, we
are authorised to regard them as part of the present order of nature,
and they may be introduced into geological speculations respecting the
past, provided that we do not imagine them to have been more frequent
or general than we expect them to be in time to come (vol. i. p. 89).
Again:--
If we regard each of the causes separately, which we know to be at
present the most instrumental in remodelling the state of the surface,
we shall find that we must expect each to be in action for thousands of
years, without producing any extensive {274} alterations in the
habitable surface, and then to give rise, during a very brief period,
to important revolutions (vol. ii. p. 161).[70]
Lyell quarrelled with the catastrophists then, by no means because they
assumed that catastrophes occur and have occurred, but because they had got
into the habit of calling on their god Catastrophe to help them, when they
ought to have been putting their shoulders to the wheel of observation of
the present course of nature, in order to help themselves out of their
difficulties. And geological science has become what it is, chiefly because
geologists have gradually accepted Lyell's doctrine and followed his
precepts.
So far as I know anything about the matter, there is nothing that can be
called proof, that the causes of geological phenomena operated more
intensely or more rapidly, at any time between the older tertiary and the
oldest palaeozoic epochs than they have done between the older tertiary
epoch and the present day. And if that is so, uniformitarianism, even as
limited by Lyell,[71] has no call to lower its crest. But if the facts were
otherwise, the position Lyell took up remains {275} impregnable. He did not
say that the geological operations of nature were never more rapid, or more
vast, than they are now; what he did maintain is the very different
proposition that there is no good evidence of anything of the kind. And
that proposition has not yet been shown to be incorrect.
I owe more than I can tell to the careful study of the _Principles of
Geology_ in my young days; and, long before the year 1856, my mind was
familiar with the truth that "the doctrine of uniformity is not
incompatible with great and sudden changes," which, as I have shown, is
taught _totidem verbis_ in that work. Even had it been possible for me to
shut my eyes to the sense of what I had read in the _Principles_, Whewell's
_Philosophy of the Inductive Sciences_, published in 1840, a work with
which I was also tolerably familiar, must have opened them. For the always
acute, if not always profound, author, in arguing against Lyell's
uniformitarianism, expressly points out that it does not in any way
contravene the occurrence of catastrophes.
With regard to such occurrences [earthquakes, deluges, etc.], terrible
as they appear at the time, they may not much affect the {276} average
rate of change: there may be a _cycle_, though an irregular one, of
rapid and slow change: and if such cycles go on succeeding each other,
we may still call the order of nature uniform, notwithstanding the
periods of violence which it involves.[72]
The reader who has followed me through this brief chapter of the history of
geological philosophy will probably find the following passage in the paper
of the Duke of Argyll to be not a little remarkable:--
Many years ago, when I had the honour of being President of the British
Association,[73] I ventured to point out, in the presence and in the
hearing of that most distinguished man [Sir C. Lyell] that the doctrine
of uniformity was not incompatible with great and sudden changes, since
cycles of these and other cycles of comparative rest might well be
constituent parts of that uniformity which he asserted. Lyell did not
object to this extended interpretation of his own doctrine, and indeed
expressed to me his entire concurrence.
I should think he did; for, as I have shown, there was nothing in it that
Lyell himself had not said, six-and-twenty years before, and enforced,
three years before; and it is almost verbally identical with the view of
uniformitarianism taken by Whewell, sixteen years before, in a work with
which, one would think, that any one who undertakes to discuss the
philosophy of science should be familiar.
Thirty years have elapsed since the beginner of 1856 persuaded himself that
he enlightened the foremost geologist of his time, and one of the most
acute and far-seeing men of science of any time, as to the scope of the
doctrines which the veteran philosopher {277} had grown gray in
promulgating; and the Duke of Argyll's acquaintance with the literature of
geology has not, even now, become sufficiently profound to dissipate that
pleasant delusion.
If the Duke of Argyll's guidance in that branch of physical science, with
which alone he has given evidence of any practical acquaintance, is thus
unsafe, I may breathe more freely in setting my opinion against the
authoritative deliverances of his Grace about matters which lie outside the
province of geology.
And here the Duke's paper offers me such a wealth of opportunities that
choice becomes embarrassing. I must bear in mind the good old adage, "Non
multa sed multum." Tempting as it would be to follow the Duke through his
labyrinthine misunderstandings of the ordinary terminology of philosophy,
and to comment on the curious unintelligibility which hangs about his
frequent outpourings of fervid language, limits of space oblige me to
restrict myself to those points, the discussion of which may help to
enlighten the public in respect of matters of more importance than the
competence of my Mentor for the task which he has undertaken.
I am not sure when the employment of the word Law, in the sense in which we
speak of laws of nature, commenced, but examples of it may be found in the
works of Bacon, Descartes, and Spinoza. Bacon employs "Law" as the
equivalent of "Form," and I am inclined to think that he may be responsible
for a good deal of the confusion that has subsequently {278} arisen; but I
am not aware that the term is used by other authorities, in the seventeenth
and eighteenth centuries, in any other sense than that of "rule" or
"definite order" of the coexistence of things or succession of events in
nature. Descartes speaks of "regles, que je nomme les lois de la nature."
Leibnitz says "loi ou regle generale," as if he considered the terms
interchangeable.
The Duke of Argyll, however, affirms that the "law of gravitation" as put
forth by Newton was something more than the statement of an observed order.
He admits that Kepler's three laws "were an observed order of facts and
nothing more." As to the law of gravitation, "it contains an element which
Kepler's laws did not contain, even an element of causation, the
recognition of which belongs to a higher category of intellectual
conceptions than that which is concerned in the mere observation and record
of separate and apparently unconnected facts." There is hardly a line in
these paragraphs which appears to me to be indisputable. But, to confine
myself to the matter in hand, I cannot conceive that any one who had taken
ordinary pains to acquaint himself with the real nature of either Kepler's
or Newton's work could have written them. That the labours of Kepler, of
all men in the world, should be called "mere observation and record," is
truly wonderful. And any one who will look into the _Principia_, or the
_Optics_, or the _Letters to Bentley_, will see, even if he has no more
special knowledge of the topics discussed than I have, that Newton over and
over again insisted that he had {279} nothing to do with gravitation as a
physical cause, and that when he used the terms attraction, force, and the
like, he employed them, as he says, "_mathematice_" and not "_physice_".
How these attractions [of gravity, magnetism, and electricity] may be
performed, I do not here consider. What I call attraction may be
performed by impulse or by some other means unknown to me. I use that
word here to signify only in a general way any force by which bodies
tend towards one another, whatever be the cause.[74]
According to my reading of the best authorities upon the history of
science, Newton discovered neither gravitation, nor the law of gravitation;
nor did he pretend to offer more than a conjecture as to the causation of
gravitation. Moreover, his assertion that the notion of a body acting where
it is not, is one that no competent thinker could entertain, is
antagonistic to the whole current conception of attractive and repulsive
forces, and therefore of "the attractive force of gravitation." What, then,
was that labour of unsurpassed magnitude and excellence and immortal
influence which Newton did perform? In the first place, Newton defined the
laws, rules, or observed order of the phenomena of motion, which come under
our daily observation, with greater precision than had been before
attained; and, by following out with marvellous power and subtlety the
mathematical consequences of these rules, he almost created the modern
science of pure mechanics. In the second place, applying exactly the same
method {280} to the explication of the facts of astronomy as that which was
applied a century and a half later to the facts of geology by Lyell, he set
himself to solve the following problem. Assuming that all bodies, free to
move, tend to approach one another as the earth and the bodies on it do;
assuming that the strength of that tendency is directly as the mass and
inversely as the squares of the distances; assuming that the laws of
motion, determined for terrestrial bodies, hold good throughout the
universe; assuming that the planets and their satellites were created and
placed at their observed mean distances, and that each received a certain
impulse from the Creator; will the form of the orbits, the varying rates of
motion of the planets, and the ratio between those rates and their
distances from the sun which must follow by mathematical reasoning from
these premisses, agree with the order of facts determined by Kepler and
others, or not?
Newton, employing mathematical methods which are the admiration of adepts,
but which no one but himself appears to have been able to use with ease,
not only answered this question in the affirmative, but stayed not his
constructive genius before it had founded modern physical astronomy.
The historians of mechanical and of astronomical science appear to be
agreed that he was the first person who clearly and distinctly put forth
the hypothesis that the phenomena comprehended under the general name of
"gravity" follow the same order throughout the universe, and that all
material bodies exhibit these phenomena; so that, in this sense, the {281}
idea of universal gravitation may, doubtless, be properly ascribed to him.
Newton proved that the laws of Kepler were particular consequences of the
laws of motion and the law of gravitation--in other words, the reason of
the first lay in the two latter. But to talk of the law of gravitation
alone as the reason of Kepler's laws, and still more as standing in any
causal relation to Kepler's laws, is simply a misuse of language. It would
really be interesting if the Duke of Argyll would explain how he proposes
to set about showing that the elliptical form of the orbits of the planets,
the constant area described by the radius vector, and the proportionality
of the squares of the periodic times to the cubes of the distances from the
sun, are either caused by the "force of gravitation" or deducible from the
"law of gravitation." I conceive that it would be about as apposite to say
that the various compounds of nitrogen with oxygen are caused by chemical
attraction and deducible from the atomic theory.
Newton assuredly lent no shadow of support to the modern pseudo-scientific
philosophy which confounds laws with causes. I have not taken the trouble
to trace out this commonest of fallacies to its first beginning; but I was
familiar with it in full bloom, more than thirty years ago, in a work which
had a great vogue in its day--the _Vestiges of the Natural History of
Creation_--of which the first edition was published in 1844.
It is full of apt and forcible illustrations of {282} pseudoscientific
realism. Consider, for example, this gem serene. When a boy who has climbed
a tree loses his hold of the branch, "the law of gravitation unrelentingly
pulls him to the ground, and then he is hurt," whereby the Almighty is
quite relieved from any responsibility for the accident. Here is the "law
of gravitation" acting as a cause in a way quite in accordance with the
Duke of Argyll's conception of it. In fact, in the mind of the author of
the _Vestiges_, "laws" are existences intermediate between the Creator and
his works, like the "ideas" of the Platonisers or the Logos of the
Alexandrians.[75] I may cite a passage which is quite in the vein of
Philo:--
We have seen powerful evidences that the construction of this globe and
its associates; and, inferentially, that of all the other globes in
space, was the result, not of any immediate or personal exertion on the
part of the Deity, but of natural laws which are the expression of his
will. What is to hinder our supposing that the organic creation is also
a result of natural laws which are in like manner an expression of his
will? (p. 154, 1st edition).
And creation "operating by law" is constantly cited as relieving the
Creator from trouble about insignificant details.
I am perplexed to picture to myself the state of mind which accepts these
verbal juggleries. It is intelligible that the Creator should operate
according to such rules as he might think fit to lay down for himself (and
therefore according to law); but that would leave the operation of his will
just as much a direct personal act as it would be under any other {283}
circumstances. I can also understand that (as in Leibnitz's caricature of
Newton's views) the Creator might have made the cosmical machine, and,
after setting it going, have left it to itself till it needed repair. But
then, by the supposition, his personal responsibility would have been
involved in all that it did, just as much as a dynamiter is responsible for
what happens when he has set his machine going and left it to explode.
The only hypothesis which gives a sort of mad consistency to the
Vestigiarian's views is the supposition that laws are a kind of angels or
demiurgoi, who, being supplied with the Great Architect's plan, were
permitted to settle the details among themselves. Accepting this doctrine,
the conception of royal laws and plebeian laws, and of those more than
Homeric contests in which the big laws "wreck" the little ones, becomes
quite intelligible. And, in fact, the honour of the paternity of those
remarkable ideas which come into full flower in the preacher's discourse,
must, so far as my imperfect knowledge goes, be attributed to the author of
the _Vestiges_.
But the author of the _Vestiges_ is not the only writer who is responsible
for the current pseudo-scientific mystifications which hang about the term
"law." When I wrote my paper about "Scientific and Pseudo-Scientific
Realism," I had not read a work by the Duke of Argyll, _The Reign of Law_,
which, I believe, has enjoyed, possibly still enjoys, a widespread
popularity. But the vivacity of the Duke's attack led me to think it
possible that criticisms directed elsewhere might have come home to {284}
him. And, in fact, I find that the second chapter of the work in question,
which is entitled "Law; its definitions," is, from my point of view, a sort
of "summa" of pseudo-scientific philosophy. It will be worth while to
examine it in some detail.
In the first place, it is to be noted that the author of the _Reign of Law_
admits that "law," in many cases, means nothing more than the statement of
the order in which facts occur, or, as he says, "an observed order of
facts" (p. 66). But his appreciation of the value of accuracy of expression
does not hinder him from adding, almost in the same breath, "In this sense
the laws of nature are simply those facts of nature which recur according
to rule" (p. 66). Thus "laws," which were rightly said to be the statement
of an order of facts in one paragraph, are declared to be the facts
themselves in the next.
We are next told that, though it may be customary and permissible to use
"law" in the sense of a statement of the order of facts, this is a low use
of the word; and indeed, two pages farther on, the writer, flatly
contradicting himself, altogether denies its admissibility.
An observed order of facts, to be entitled to the rank of a law, must
be an order so constant and uniform as to indicate necessity, and
necessity can only arise out of the action of some compelling force (p.
68).
This is undoubtedly one of the most singular propositions that I have ever
met with in a professedly scientific work, and its rarity is embellished by
another direct self-contradiction which it implies. For {285} on the
preceding page (67), when the Duke of Argyll is speaking of the laws of
Kepler, which he admits to be laws, and which are types of that which men
of science understand by "laws," he says that they are "simply and purely
an order of facts." Moreover, he adds: "A very large proportion of the laws
of every science are laws of this kind and in this sense."
If, according to the Duke of Argyll's admission, law is understood, in this
sense, thus widely and constantly by scientific authorities, where is the
justification for his unqualified assertion that such statements of the
observed order of facts are not "entitled to the rank" of laws?
But let us examine the consequences of the really interesting proposition I
have just quoted. I presume that it is a law of nature that "a straight
line is the shortest distance between two points." This law affirms the
constant association of a certain fact of form with a certain fact of
dimension. Whether the notion of necessity which attaches to it has an _a
priori_ or an _a posteriori_ origin is a question not relevant to the
present discussion. But I would beg to be informed, if it is necessary,
where is the "compelling force" out of which the necessity arises; and
further, if it is not necessary, whether it loses the character of a law of
nature?
I take it to be a law of nature, based on unexceptionable evidence, that
the mass of matter remains unchanged, whatever chemical or other
modifications it may undergo. This law is one of the foundations of
chemistry. But it is by no means necessary. It {286} is quite possible to
imagine that the mass of matter should vary according to circumstances, as
we know its weight does. Moreover, the determination of the "force" which
makes mass constant (if there is any intelligibility in that form of words)
would not, so far as I can see, confer any more validity on the law than it
has now.
There is a law of nature, so well vouched by experience, that all mankind,
from pure logicians in search of examples to parish sextons in search of
fees, confide in it. This is the law that "all men are mortal." It is
simply a statement of the observed order of facts that all men sooner or
later die. I am not acquainted with any law of nature which is more
"constant and uniform" than this. But will any one tell me that death is
"necessary"? Certainly there is no _a priori_ necessity in the case, for
various men have been imagined to be immortal. And I should be glad to be
informed of any "necessity" that can be deduced from biological
considerations. It is quite conceivable, as has recently been pointed out,
that some of the lowest forms of life may be immortal, after a fashion.
However this may be, I would further ask, supposing "all men are mortal" to
be a real law of nature, where and what is that to which, with any
propriety, the title of "compelling force" of the law can be given?