GROWTH OF THE MECHANICAL THEORY
DECLINE OF SCHOLASTICISM.--By the time of Lord Bacon, the Scholastic
philosophy might have been described as extinct; it no longer survived
as a living system. The loss was a serious one to mankind, which was
poorer by the discrediting of an authoritative body of thought, a
possession it seems ill able to dispense with. The Baconian philosophy
was an imperfect substitute; it was little more than a system of
enquiry, a manual of scientific procedure, for Bacon himself was not in
the philosophical sense a profound or constructive thinker, though he
was one of those men of talent who can give utterance to the tendencies
of an epoch.
THE NEW PHILOSOPHY.--The task, however, of constructing a new philosophy
of the universe was courageously taken in hand by a succession of
thinkers, and the energy of thought which the great problem generated is
characteristic of perhaps the most vigorous century of European
history--the seventeenth.
The tendency of the new discoveries in science had not been obscure, and
Modern Philosophy starts with an attempt to represent the universe as a
self-working machine--a co-ordinated whole, throughout which the
principles of mathematics are universally valid. The trend of ideas set
in motion by the new discoveries in astronomy seemed to point in this
direction. But to introduce mechanics into the celestial regions, though
an important step, was but a beginning. Mechanics must be _universally_
valid--even in the human body--or the new teaching was vain. Exceptions
may prove a rule, but they destroy a philosophy.
THE SUBJUGATION OF PHYSIOLOGY.--It was an Englishman who provided the
necessary facts to fill the gravest gap in the mechanical theory. It was
already known in the previous century that the blood of animals
circulated throughout the body; the existence and use of veins and
heart-valves was also known, but it was William Harvey (1578-1657) who
discovered the heart to be the organ responsible for _maintaining_ the
circulation of the blood, by purely mechanical means. This was a fact of
the utmost significance. In the sphere of physiology, where theories
about mysterious powers of blood or soul had been hitherto
authoritative, it effected a revolution. Indeed it is true to say that
Harvey "is to physiology what Galileo was to physics." He proved that
"the general laws of motion are valid within as well as without the
organism"--an important extension of the mechanical theory.
DESCARTES.--Among the leading men who accepted Harvey's theory, one of
the first was Rene Descartes (1596-1650). Well might this thinker
welcome it, for it was a most important contribution to the imposing
philosophic fabric for which he was industriously collecting materials.
Descartes, apart from his philosophical speculations, is an interesting
character, being a Frenchman of noble birth who was educated by the
Jesuits, saw something of contemporary life in Paris, served as a
military officer in Holland and Germany, and made some original
discoveries in mathematics.
The mathematical mind, accustomed as it is to deal with highly abstract
ideas, takes kindly to metaphysics. And it very often solves the mystery
of the universe by expressing all its contents in mathematical terms.
Such, at least, was Descartes' method. The simplest and clearest ideas
which we can have of anything are mathematical, i.e. extension and
mobility. And it is by concentrating our attention upon this simple and
mathematical aspect of things that we shall arrive at a proper
understanding of all that goes on in the material world.
UNIVERSALITY OF MATHEMATICS.--A phenomenon was, in Descartes' eyes,
"explained" only when a "cause" which is its exact _mathematical
equivalent_, has been indicated. The "cause" and the "effect" are two
sides of a mathematical equation (_Causa aequat effectum_). Anything
that happens in the material world (the fall of a stone, the beat of a
heart, the rising of the sun) is really nothing more than a
redistribution of portions of that sum of motion which, once generated
at the Creation, has remained unaltered, and unalterable, in the
universe ever since. The sum of motion is constant, there can be no
addition to or subtraction from it. In this sense it would be true that
"there is nothing new under the sun": only ever-new distributions of the
old.
THE UNIVERSE A MACHINE.--Once assume that all phenomena can be
interpreted in terms of motion, and add the proposition (already
enunciated by Galileo) that motion once set going will proceed for ever,
unless some impediment from outside intervenes, and the mechanical view
of the universe is complete. The universe is a machine, i.e. a thing
that works (1) according to mathematical principles, (2) automatically.
ELABORATIONS OF THE MECHANICAL THEORY.--The importance of Descartes lies
not in his having invented this conception (we have already seen it in
the hands of Leonardo da Vinci, Galileo, and others), but in his having
elaborated it. This he did in two directions: (1) he attempted to supply
a mechanical theory of the evolution of the world-system; _i.e._ to show
how the heavenly bodies came into being by natural and mechanical
processes; (2) he applied the mechanical theory to organisms; animals
and men were complex machines. (Here, as we have seen, the discovery of
Harvey was of prime importance.)
It is hardly necessary to describe at length Descartes' mechanical
theory of the evolution of the world-system, though an interest attaches
to it as being the ancestor of the modern "nebular hypothesis." Matter
in whirling motion around fixed centres is the original _datum_ from
which Descartes evokes the universe. With regard to the mechanical
theory of organisms, Descartes developed it at some length in various
treatises. All the functions and actions of animals were regarded by him
as entirely involuntary and mechanical. "That the lamb flees at the
sight of a wolf happens because the rays of light from the body of the
wolf strike the eye of the lamb, and set the muscles in motion by means
of the 'reflex' currents of the animal spirits."
In the case of human beings, owing to the phenomenon of "consciousness,"
Descartes felt compelled to assume a "soul"--a _thinking_ substance in
reciprocal action with the _material_ substance (of the brain). This,
too, is an anticipation of the modern theory of "psycho-physical
parallelism."
CARTESIANISM.--The ideas of Descartes had considerable influence among
his contemporaries, and Cartesianism, as it was called, became
fashionable in intellectual circles. It developed a tendency towards
free enquiry and independent thought; and it was even more significant
as an atmosphere than as a system of ideas. Though in this respect too,
it was both important and vital; as we have observed, modern mechanical
theories find their parent in Descartes.
Nor was it only, we may remark, among philosophers and men of science
that Cartesian ideas were popular; they were accepted and elaborated by
the religious thinkers who hoped to harmonise and humanise theology and
science. Pascal, Bossuet and Fenelon, the finest minds in the French
Church, were eager Cartesians.[5]
This aspect of the matter, i.e. the significance of Cartesianism for
religion, we can for the present postpone.
RESULTS SO FAR.--Successive breaches in the Scholastic system have now
been noted. Copernicus had introduced a new astronomy, Galileo a new
physics, Descartes (with the help of Harvey) a new physiology, and the
beginnings of a new psychology.
CONTRIBUTIONS OF HOBBES.--The step that remained was taken by an
Englishman, Thomas Hobbes (1588-1679), who attempted to provide a system
of ethics and a theory of politics upon a purely naturalistic basis.
Hobbes was a particularly energetic thinker. He worked out a psychology
of the feelings, which reduced everything to the impulse of
self-preservation and the instinct for power. Men were induced by these
instincts to agree to certain rules of conduct, for the sake of
expediency. Social life seems essential if men are to live together--the
instinct of self-preservation demands it--and social life in turn
demands certain renunciations: thus fidelity, gratitude, forbearance,
justice, etc., must be practised.
Thus Hobbes attempted to banish all mysterious or obscure forces from
morality, which was the characteristic and inevitable product of human
nature and human circumstances. This way of looking at things seemed
strange to all, and even revolting to some, of Hobbes' contemporaries.
As the mystical powers of motion which the Scholastics had believed in
were banished by the new physics and the new physiology, so the new
psychology could allow of no mystical faculty which can decide in all
problems of good and evil.
With Hobbes, then, a naturalistic view of the universe may be said to
have been tolerably complete: it embraces physics, psychology, and
ethics. There still remained, of course, a number of gaps in scientific
knowledge, and consequently any philosophy based thereupon could not yet
be regarded as secure. These gaps, however, as research proceeded and
successive discoveries were made, tended to diminish both in size and
quantity.
NEWTON.--The seventeenth and the early eighteenth centuries were
fruitful in revelations of this kind, and natural knowledge steadily and
even rapidly progressed. And one thinker, who may be regarded as a link
between the seventeenth century and that which succeeded it, may now
claim our attention.
The name of Newton (1642-1727) is as familiar to Englishmen as that of
Shakespeare, and the discovery by him of the "law of gravitation" is one
of those scraps of information which we acquire, and perhaps fail to
understand, in early childhood.
Newton's scientific method is a no less important aspect of his work
than its results. The _Principia_, in which he gave his discovery to the
world, is "a model for all scientific investigations which has never
been surpassed." It was, indeed, a brilliant application of the
principle of inferring the unknown from the already known, without any
dogmatic leaps in the dark. The principle with which he began was that
what is true in the narrower spheres of experience (e.g. in the case of
an apple falling) is true also in the wider spheres (e.g. in the
movements of the celestial bodies). He then made a careful mathematical
deduction of what would happen in the case of the planets, assuming that
the laws of falling bodies on the earth were applicable to them also.
And he concluded by showing that what would happen according to
mathematics under this assumption _actually does happen_. The conclusion
follows that the same force, i.e. "attraction," operates in both cases.
It is no wonder that this final and successful operation was performed
by Newton "in a state of excitement so great that he could hardly see
his figures."
SIGNIFICANCE OF HIS DISCOVERY.--The philosophic importance of the
discovery that the motions of the planets may be explained by the "law
of gravitation" was twofold. In the first place, it now became possible
to understand how the universe held together (a problem which the new
astronomy had not solved); and in the second place, the theory
constituted a large extension of the mechanical view. It demonstrated
that "the physical laws which hold good on the surface of the earth are
valid throughout the universe, so far as we can know anything of it."
Thus the area of existence in which physical law held good was at once
infinitely widened. The mechanical theories of Galileo, Descartes, and
others, not only received confirmation, but became more comprehensive
than before.
So that Newton may be said to have put the finishing touch upon the
achievements of his predecessors, and to have crowned their labours with
success. And his work has the characteristic of permanency: his
"gravitation formula" has stood the test of time. "It still stands
there," says a careful and authoritative writer, "as almost the only
firmly established mathematical relation, expressive of a property of
all matter, to which the progress of more than two centuries has added
nothing, and from which it has taken nothing away."[6]
RELIGIOUS COROLLARIES.--It would be a profound mistake to assume that
the creators of the mechanical view, as it has hitherto met us, were
animated by any hostility to religion. Nor did they believe their
theories to involve any disastrous consequences in that sphere.
The new astronomy of Copernicus had actually been made the basis of a
spiritual view of the universe by the profound genius (both
philosophical and religious) of Giordano Bruno. And the fact that the
ecclesiastical authorities rejected his view need not divest it of
importance or of value in our eyes. Bruno's own faith was not disturbed
by the infidelity of his persecutors. "Ye who pass judgment upon me
feel, maybe, greater fear than I upon whom it is passed," were his last
words to them. Had they _believed_, they need not have been afraid, and
might have been content with the policy of Gamaliel.
As for Descartes and Hobbes, their notions were no doubt distasteful to
conservative minds (the Jesuits were no friends to either), but
Descartes regarded himself, and would fain have been regarded by others,
as a good Catholic; and Hobbes, theologically, was what in these days we
might call a Liberal Protestant. Cartesianism, as we have seen, came to
be a name for a type of thought which studied to harmonise science and
theology, and one of the most profound religious geniuses of any
age--Pascal, was (as we have seen) a Cartesian.
As for Newton, his view of the universe was essentially a religious one,
though he did not allow theological speculations to intrude upon his
strictly scientific work. His attitude is indicated by a reply to the
inquiry of a contemporary theologian as to how the movements and
structure of the solar system were to be accounted for.
"To your query I answer that the motions which the planets now have
could not spring from any natural cause alone.... To compare and adjust
all these things together (i.e. quantities of matter and gravitating
powers, etc.) in so great a variety of bodies, argues the cause to be
not blind and fortuitous, but very well skilled in mechanism and
geometry."[7]
Still, the mechanical view contained within it sinister possibilities;
and the instincts of conservative thinkers were not altogether at fault.
The mechanical view in itself need not be hostile to a spiritual and
rational religion (though it is fatal to most forms of superstition);
and yet that view can be used in the interests of anti-religious
prejudice--and, as we shall see, it was so used, and with considerable
effect.
Meanwhile, however, we shall pass on to consider the work of three
thinkers who are typical of a revolt from what was in danger of becoming
the all-absorbing tyranny of mechanics. This reaction (for so it may be
termed) we shall proceed, in the following chapter, to examine.