CHAPTER I
FROM
THALES TO KANTVery
few even of the most savage tribes are content to take the world
just
as it is without speculating as to how it came to be. For time has
three dimensions—past, present, and future—and we can no more
restrict our thoughts within one of them than we can exist
corporeally in Flatland. We are, indeed, told that the Abipones and
Esquimaux refuse to trouble themselves with questions of origin, on
the ground that the hard facts of life leave no room for otiose
discussions; but even they feel obliged to justify their
incuriosity.
In easier circumstances they, too, would claim the entirely human
privilege of 'looking before and after,' as their forgotten
progenitors may have done. It is, indeed, difficult to think
atall
about the framework of nature without attempting to divine, were it
only by a crude surmise, the process of its construction. We are
instinctively convinced that there is no such thing as fixity of
condition. So far, Heracleitus was in the right.Experience
tells us of continual change in ourselves and whatever surrounds
us.
Reason teaches us that its minute momentary effects, if pursued
backward for an indefinite time, must sum up to a prodigious total.
No limit, that is to say, can be put to the difference between what
is and what was. Yet the machinery of modification must somehow
have
been set going. An initial state is prescribed by logical
necessity.
And the start was made on certain terms—it was 'conditioned.' But
the conditioned implies the absolute; ordinances, an enactive
power.
The inevitableness of the connection has been more or less
obscurely
perceived wherever men have tried to establish some kind of accord
between phenomena and intuition, with results legible in the
wavering
outlines of many primitive cosmogonies. Only, however, in the
Hebrew
Scriptures has the idea of Creation been realizedin
all its fulness and freedom; elsewhere the gods invoked to bring
the
world into existence themselves demanded a birth-history, a
theogony
being the usual and necessary prelude to a cosmogony.Nevertheless
'picture-thoughts' (it has been well said),[1]and
nothing more, were represented by these prefatory genealogies.
Night
and darkness loomed into personal shape, and from the obscurity of
their union the creatures of light radiantly sprang, and proceeded,
according to a predetermined law of order, to sort out the elements
of chaos and dispose them into cosmical harmony.This
mythical phase of thought terminated in Greece with the rise of the
Ionian School of Philosophy. Immemorial legends, discredited by the
advent of a new wisdom, took out a fresh lease of life under the
guise of folk-lore; Orphic fables were left to the poets and the
people; and the sage of Miletus set on foot a speculative
tradition,
maintained by a long succession of metaphysicians down to the very
threshold of the recent scientific epoch. Allwere
what we should call evolutionists—Thales of Miletus no less than
Descartes and Swedenborg; their main object, in other words, was to
find a practicable mode of evoking a systematic arrangement of
related parts from the monotony of undifferentiated confusion. Now,
in essaying this enterprise they encountered two distinct problems.
One was concerned with the nature of the primeval world-stuff; the
other with the operations to which it had been submitted. Modern
theorists have made it their primary object to expound the
mechanism
of cosmic growth—the play of forces involved in it, the
transformations and progressive redistribution of energy attending
it. But questions of this kind could only in the scantiest measure
be
formulated by early thinkers, who accordingly devoted their chief
attention to selecting an appropriate material for the exercise of
their constructive ingenuity.Thales
asserted all things to have been derived from water, and water is
still among unsophisticated tribes the favourite 'Urstoff.'
Anaximenes substituted air. Heracleitus gave the preference to the
mobile and vital element (as he thought it) of fire. Anaximander,
onthe
other hand, might put forward a colourable claim to priority over
Sir
William Crookes in the invention of 'protyle.' He imagined as the
matrix of the world a boundless expanse of generalized matter,
containing potentially all the chemical species, which, separating
out by degrees through the affinity of like for like, formed, by
their contrasts and conjunctions, the infinitely varied sum of
things. The successors of Anaximander had recourse to spontaneously
arising condensations and rarefactions as the mainspring of
development; but all these vague principles were quickly crowded
into
oblivion by the definite and intelligible doctrine of the 'four
elements' enunciated by Empedocles, which, guaranteed by the
imprimatur of Plato, took a place unchallenged for nearly two
millenniums among the fundamentals of science. Erroneous and
misleading though it was, it yet served as a means of regulating
appearances and guiding vagrant ideas—it was a track to follow in
the absence of any better method of orientation.Leucippus
and his more famous disciples, Democritus and Epicurus, were the
first who ventured to trace the mechanical history ofthe
cosmos. Their primordial atoms were endowed with weight, and it was
weight or gravity which ultimately determined their spacial
arrangement and mutual relations. Rectilinear in the first draft of
the scheme, their movements were somewhat arbitrarily deflected by
Epicurus; and the gyrations thence ensuing eventually became, so to
speak, authentic and precise in the Cartesian vortices and in
Swedenborg's solar maelstrom. Kant's
Natural History of
the universe was another, though an entirely separate branch of the
atomistic stock. The Democritean atoms, however, and in a lesser
degree the Kantian atoms, differed essentially from the ultimates
of
chemical analysis postulated by Dalton. They were a scratch lot—an
incongruous assortment of fragments, rather than of elementary
portions of matter, indefinitely various in size, shape, and
mass.Nor
was this diversity created as a mere play of fancy. It was strictly
necessary to the plan of action adopted. For, apart from
heterogeneity, there could obviously be no development. Absolute
uniformity involves absolute permanence. Change can
originateonly
through inequality. There must be a tilt of level before the
current
will begin to flow; some cause of predominance is needed to set it
going in a given direction. Here, of a surety, is the initial crux
of
all cosmogonists. They usually surmount it by assuming the
occurrence
of casual condensations, secure against disproof, while incapable
of
verification. The expedient thus begs the question.Theories
of world-history made an integral part of antique philosophy. Each
founder of a school aimed at establishing a complete system of
knowledge, co-extensive with phenomena, embracing all things, from
the primum mobile
overhead to the blade of grass underfoot, and rationalizing the
past,
present, and future of the comprehensive whole. Modern science is
less ambitious. Aspiring to no such vast synthesis, it is content
to
make laborious acquaintance with the facts of nature, to ponder
their
implications, and, if possible, to reconstruct on the basis
supplied
by them the condition of things in the 'dim backward' of unmeasured
time. By no such means, it is true, can their beginning in any real
sense be arrived at; the weapons of induction becomeblunted
long before they strike home to the heart of that mystery; yet the
recognition of their inadequacy brings compensation in a fuller
mastery over their properly adapted use. Science, so called, was,
indeed, down to the Baconian era, a turbid mixture of physics with
metaphysics. The solution, it might be said, was attempted of an
insoluble material which refused to dissolve and was hindered from
precipitating.The
Greek view of nature was essentially pantheistic. The Ionian
speculators appear to have presumed without expressly insisting
upon
its self-regulating power. Aristotle alone emphatically rejected
the
doctrine of cosmic vitality or sub-conscious tendencies. But Plato
accepted and magnified the Oriental tradition; the conception of a
'World-Soul' owed to him its vague splendour and perennial
fascination. The function of the Platonic vice-creator (for such
the
World-Soul must be accounted) was that of moulding brute matter
into
conformity with the archetypal ideas of the Divine mind; this was
not, however, accomplished once for all, but by a progressive
spiritualizing of what in its nature was deadand
inanimate. The spiritual agent, becoming incorporated with the
universal frame, lent to it a semblance of life, an obscure
sensitiveness, and even some kind of latent intelligence; and so
the
anima mundi was
shaped into existence, and continued century by century to be the
subject and source of imaginings beyond measure wild and
fantastic.One
great thought—that of the unity of nature—lay behind them, but
its significance was lost amid the phantasmagoria of Neo-Platonist
exaltations. Hence the Bacchic fervours of Giordano Bruno took
their
inspiration; here was the groundwork of Spinoza's pantheism.
Shelley's Demiorgon, felt as 'a living spirit,' seen as 'a mighty
darkness,' descended lineally from that strange essence—formless,
inarticulate, devoid of individual self-consciousness—which
animated the submerged philosophy of Neo-Pagan times with the
barren
ardours of mysticism. The doctrine, in its original and more sober
version, obtained memorable expression in Virgil's melodious
hexameters:'Principio
cœlum, ac terras, camposque liquentes,Lucentemque
globum lunæ, Titaniaque astra,Spiritus
intus alit, totamque infusa per artusMens
agitat molem, et magno se corpore miscet.'In
Conington's rhymed version they run as follows:'Know
first, the heaven, the earth, the main,The
moon's pale orb, the starry train,Are
nourished by a soul,A
bright intelligence, whose flameGlows
in each member of the frame,And
stirs the mighty whole.'Kepler
was no cosmogonist, but he aspired to found a 'physical astronomy,'
and in his gropings for a mechanical power that might suffice to
regulate the movements of the heavenly bodies, he stumbled upon a
mode of action highly appropriate for the explanation of their
growth. His ignorance of the laws of motion precluded him from the
conception of velocities persistent in themselves, and merely
deflected from straight into curved paths by a constant central
pull.
Hence he was driven to the twofold expedient of creating a whirling
medium for maintaining the revolutions of the planets, and of
supposing the sun to exercise a 'magnetic influence,' by which they
were drawn into closed orbits. Here, then, central forces made a
definitive entry on the astronomical
stage, although with scarcely a discernible promise of their
brilliant future. But it was otherwise with the clumsy machinery
they
helped to animate. Kepler's simple
modus operandi,
adopted, or more probably re-invented by Descartes, was published
as
an epoch-making discovery in his
Principia Philosophica
(1644), and sprang under its new aspect into swift notoriety. The
wide acceptance of the theory of vortices was at least in part due
to
the impressive largeness of its framework. Descartes left nothing
out. The spacious scope of his speculations embraced all that was
knowable—nature, animate and inanimate, life and time:'Planets
and the pale populace of heaven,The
mind of man, and all that's made to soar.'A
philosophy, a metaphysic, and a cosmogony were linked together in a
single plan. Its author distinguished in matter three gradations of
fineness. The coarsest kind was that composing the earth and other
opaque bodies; the more sublimated materials of the sun and stars
came next; finally, there was the ethereal substance of the skies,
so
delicately constituted as to be luminous or luminiferous.This
last variety was regarded as of subordinate origin. It represented,
in fact, a kind of celestial detritus. Interstellar space had
gradually become filled with intangible dust, the product of
molecular attrition among originally angular solar and stellar
particles. Ether was thus supposed to bear to the subtlest
description of ordinary matter very much the same sort of
relationship that ions presumably do to atoms.Enough
has been said to show that the Cartesian universe was based on
crude
atomism. Its mode of construction, moreover, evinced a total
disregard of mechanical principles. Yet some acquaintance with the
laws of motion was by that time easily within reach. The first of
the
three, at any rate, had been unmistakably enounced by Galileo in
1632, and Descartes himself strongly championed its validity. Yet
he
thought it necessary, in order to keep the planets moving, to
immerse
them in one great self-gyrating vortex centred on the sun, each
being
further provided with a similar subordinate whirlpool for the
maintenance of its domestic system. Comets were left in a
singularly
anomalous position. Theycirculated
freely on the whole, their exemption from planetary restrictions
being tacitly recognized; nevertheless, they took advantage of
every
encountered swirl to help themselves on towards their
destination.Among
the fables of pseudo-science Delambre declared that, had the choice
been offered to him, he would have preferred the solid spheres of
Aristotle to the
tourbillons of
Descartes. 'The spheres,' he added,[2]'have
proved helpful both for the construction of planetariums
representing
in a general way the celestial movements, and for their calculation
by approximate rules deduced from them; but the system of vortices
has never served any purpose whatsoever, whether mechanical or
computative.'Its
vogue had, nevertheless, been brilliant and sustained. Advanced
thinkers in the time of Louis Quatorze piqued themselves upon being
Cartesians. The vortical hypothesis was novel—it seemed daring; and
though it might not be true, it had plausibility enough for
fashionable currency. Nor did it deserve the unmitigated contempt
with which it wastreated
by Delambre. A glance at the skies makes us pause before condemning
it to scornful oblivion. Just two centuries after its promulgation
the first spiral nebula was identified in Canes Venatici. That the
heavens swarm with analogous objects is certain, and their status
as
partially developed systems is visible in every line of their
conformation. Our own planetary world may, or may not, have
traversed
the stage they so copiously illustrate; but in any case they prove
beyond question that vortices variously conditioned are prevalent
among the forms assumed by cosmic masses advancing towards an
orderly
arrangement.Mystical
cosmogonies belong to the period of ethnic infancy. They have not
ceased to be current. World-fables must be invented wherever the
obscure wonder of savage communities is excited by the mysterious
spectacle of Nature's apparently designed operations and
irresistible
power. But they were superseded among peoples in the van of
progress
by philosophic cosmogonies at the epoch when Thales began to
diffuse
throughout Ionia the wisdom of the Egyptians and Chaldeans.Schemes,
however, such as he and his successors elaborated result from the
discourse of reason unfettered by any close attention to facts.
They
have been mostly wrought out by men who, in Delambre's words,
'Dissertaient à perte de vue, sans jamais rien observer, et sans
jamais rien calculer.'The
insubstantial fabrics reared by them were then fatally discredited
by
Baconian methods and the Newtonian reign of law; they
survived—forms
of thought die slowly—but insecurely, with noticeably undermined
foundations. Swedenborg was the last eminent reactionary, and his
restoration in 1734 of the Cartesian gyrating medium as the motive
power of the solar machine was a palpable failure. It could not be
otherwise, since its inceptive idea had grown superannuated. The
modern era of scientific cosmogony was at hand.It
was preceded by some remarkable attempts at sidereal
generalization.
Cosmology is the elder sister of cosmogony. What
is must be studied
before what was
can be inferred. Precedent states remain visionary unless they can
be
closely linked to actual andobservable
conditions. Now about the middle of the eighteenth century an
intelligible plan of the stellar universe, so far as the telescope
had then disclosed it, began to be a desideratum. And the
enterprise
of supplying the need was undertaken independently by two men of
obscure origin and imperfect education—one English, the other
German.Thomas
Wright, of Durham, was the son of a carpenter at Byer's Green,
where
he was born September 22, 1711. His life was one of many
vicissitudes, but ended happily. Having struggled hard for a
livelihood—now at sea, then again on shore as a clock and almanac
maker, a teacher and lecturer—he finally attained, somewhat
unaccountably, to distinction and affluence, built himself a
handsome
house hard by his native shanty, and prosperously and reputably
inhabited it during a quarter of a century. He died February 25,
1786, just one year after Herschel had described to the Royal
Society
the outcome of his first experiments in 'star gauging.' As the
originator of the 'cloven disc' theory of the Milky Way, Wright is
still deservedly remembered, for although that majestic structure
is
assuredlyotherwise
designed, it was no mean achievement to have initiated the science
of
its architecture.Heinrich
Lambert was a still more adventurous speculator than his unknown
English rival. His father was a poor tailor at Mühlhausen, then in
Swiss territory, and he worked as his apprentice. But his
irrepressible talents brought him into notice, and he died, in
1777,
through the favour of the second Frederick, a Berlin Academician.
His
Cosmological Letters,
published in 1761, were entirely original; they were composed in
ignorance of what Wright and Kant had already written. In some
respects he overtopped them both. He had splendid intuitions, and
just touched the confines of greatness. And if his performances
fell
short of the very highest, it may have been rather through
abridgment
of opportunity than through lack of capacity. The Milky Way marked,
to his apprehension, a sidereal ecliptic, and he coincided with
Wright in regarding it as a disc of aggregated stars, but with
breaches and gaps indicating a multiplicity of systems circulating,
he thought, round a common centre. Nor didhe
doubt the existence of other Milky Ways—numberless, remote,
unseen—grouped into a combination of a higher order; while beyond,
and still beyond, stretched further hierarchies of systems on an
ascending scale of magnitude and grandeur.Our
knowledge of the structural facts of the universe can never be made
exhaustive; in the middle of the eighteenth century, before
Herschel
had opened his sidereal campaign, it was barely elementary. Wright
and Lambert were accordingly on a stint of material—they had to
make bricks with very little straw. Yet they did their best with
what
was at hand. Both paid profound attention to the stellar heavens;
they earnestly sought the true interpretation of the appearances
presented by them, holding it possible, as we, despite accumulating
difficulties, still do, to harmonize countless detached phenomena
in
one vast synthetic plan.It
was this purpose of fidelity to Nature which gave value to their
work, and made it a new thing in cosmological history. This alone
lent it impulsive force, and caused the meditations of two lonely
thinkers to become effectivein
stimulating fresh attempts, favoured by improved conditions, to
comprehend what actually exists, and to infer thence, with rational
confidence, its sources in the vague but undeniable
past.FOOTNOTES:
[1]
Zeller,
History of Greek Philosophy,
translated by S.F. Alleyne, vol. i., p. 86.
[2]
Quoted
by R. Wolf, Handbuch
der Astronomie, Bd.
II., p. 593.
CHAPTER II
THE
NEBULAR HYPOTHESIS
Immanuel
Kant was, in 1751, still in the plastic stage. His period of 'pure
reason' was remote, and might have appeared improbable. Such as
they
were, his distinctions had been won in the field of concrete
science,
and the world of phenomena invited his speculations more
seductively
than the subtleties of logic. A seed was accordingly thrown into
fertile soil by his reading of Thomas Wright's
New Theory of the Universe,
as summarized in a Hamburg journal. It set him thinking, and his
thoughts proved to be of the dynamic order. Wright regarded the
heavens under a merely statical aspect. He laid down the first
definite plan of their construction, showing that the stars were
not
scattered at random, but aggregated by method; and this was
much
for
one necessitous human being to have accomplished
unaided.
But
the young professor of Königsberg could not rest satisfied with the
idle contemplation of any subsisting arrangement. His mind was
incapable of acquiescing in things simply as they presented
themselves; it craved to know further how they came to stand to
each
other in just such mutual relations. He was, moreover, permeated
with
Epicurean doctrines. Not in any reprehensible sense. He could not
be
reproached either as a hedonist or as an atheist. His pleasures
were
intellectual, his morals austere, his convictions orthodox. Behind
the veil of material existence he divined its supreme immaterial
Originator, and his perception of the activity in Nature of an
ordering First Cause remained equally vivid, whether its
disclosures
were taken to be by immediate creation or through tedious processes
of modification and growth. His large and luminous view embraced
besides the ethical significance which such processes adumbrate.
The
following sentence shows an appreciation of the place of man in
Nature truer and more profound than was attained
perhaps
by any other of his philosophical contemporaries: 'The cosmic
evolution of Nature,' he wrote in memorable words, 'is continued in
the historic development of humanity, and completed in the moral
perfection of the individual.'
[3]
Nevertheless,
he owned to a community of ideas with Democritus as to the origin
of
the universe. Lucretius had cast over him the spell of his lofty
diction, and captured his scientific adhesion by the stately
imagery
of his verse. With reservations, however. Docile discipleship was
not
in his line. He availed, then, of the Democritean atoms, but by no
means admitted their concourse to be fortuitous. Chaos itself, as
he
conceived it, half concealed, half revealed the rough draft of a
'perfect plan.' His postulates were few. He demanded only a
limitless
waste of primordial matter, animated by no forces save those of
gravitation and molecular repulsion, and undertook to produce from
it
a workable solar system. The attempt was no more than partially
successful. Retrogressive investiga
tions
lead at the best to precarious results, and this one, in
particular,
was vitiated by a fundamental error of principle. Its author
clearly
perceived that planetary circulation must be the outcome of a
vortical swirl in the nebulous matrix; but he failed to see that no
interaction of its constituent particles could have set this swirl
going.
Systems
cannot of themselves add to their 'moment of momentum.' No changes
of
internal configuration avail to increase or diminish the sum of the
products obtained by multiplying the mass of each of the connected
bodies into its areal velocity projected on a common plane. The sum
is of the algebraic kind. Equal and opposite motions cancel each
other, the total representing only the aggregate excess of speed in
either direction. A system with all its parts in rapid motion might
then conceivably be devoid of moment of momentum. And if this were
its state to begin with, it should be its state to the end of time,
unless external force were applied to alter it. But the possibility
may be dismissed as ideal. The establishment of so nice a balance
as
it would require is not practically
feasible.
In the actual world one side of the velocity account would be sure
to
exceed the other, albeit very slightly, and the smallest
predominance
would suffice to set on foot an eventual rotation of the
system.
Had
Kant been better acquainted with mechanical principles, he might
then
have safely trusted to the minute beginnings supplied by aboriginal
inequalities of movement and dissymmetry of arrangement for the
development in his colossal dust-cloud of the wheeling movement
necessary for his purpose; and he would thus have escaped stumbling
at the threshold of his daring inquiry. Rightly averse to employing
arbitrary expedients, he piqued himself on the simplicity of his
postulates, and was thus misled into substituting an imaginary for
a
real cause. The hypothesis adopted by him was that the particles
forming the initial inchoate mass fell together by gravity, but
were
deviated from rectilinear courses through the effects of unequal
resistance. And he derived from the combination of these
multitudinous encounters a common axial rotation for the entire
agglomeration. The futility of this mode of procedure was
adverted
to by M. Faye in 1885.
[4]
The
deviations in question would, in fact, exactly balance one another,
there being no reason why movement in one sense should prevail over
movement in the opposite; consequently a general rotatory movement
could not even begin to affect the seething mass, which would
condense in sterile rigidity. Kant should then, as Laplace did when
his turn came, have assumed the gyration indispensable to his
purpose. He asked too little from Nature on one side, and too much
on
the other, with the result of arresting the machinery he designed
to
set going.
Kant
made the germ of the future sun to consist in an aggregation of
atoms
at the core of the nebula, which, growing by successive innumerable
accessions, provided the motive power for the machinery of
planetary
construction. For it was, as we have seen, the jostling of the
particles drawn towards the gradually preponderating centre of
attraction which set on foot, it was supposed, the whirl eventually
transformed into the tangential velocities of the sun's attendant
bodies. They
