Professor Knight, closely resembles the idea of motion entertained by
his opponents in Toland's day. Motion was then virtually asserted to
be a thing sui generis, distinct from matter, and incapable of being
generated out of matter. Hence the obvious inference when matter was
observed to move. It was the vehicle of an energy not its own--the
repository of forces impressed on it from without--the purely passive
recipient of the shock of the Divine. The logical form continues, but
the subject-matter is changed. 'The evolution of nature,' says
Professor Knight, 'may be a fact; a daily and hourly apocalypse. But
we have no evidence of the non-vital passing into the vital.
Spontaneous generation is, as yet, an imaginative guess, unverified by
scientific tests. And matter is not itself alive. Vitality, whether
seen in a single cell of protoplasm or in the human brain, is a thing
sui generis, distinct from matter, and incapable of being generated
out of matter.' It may be, however, that, in process of time, vitality
will follow the example of motion, and, after the necessary antecedent
wrangling, take its place among the attributes of that 'universal
mother' who has been so often misdefined.
That 'matter is not itself alive' Professor Knight seems to regard as
an axiomatic truth. Let us place in contrast with this the notion
entertained by the philosopher Ueberweg, one of the subtlest heads
that Germany has produced. 'What occurs in the brain' says Ueberweg
'would, in my opinion, not be possible, if the process which here
appears in its greatest concentration did not obtain generally, only
in a vastly diminished degree. Take a pair of mice and a cask of
flour. By copious nourishment the animals increase and multiply, and
in the same proportion sensations and feelings augment. The quantity
of these latter possessed by the first pair, is not simply diffused
among their descendants, for in that case the last must feel more
feebly than the first. The sensations and feelings must necessarily be
referred back to the flour, where they exist, weak and pale it is
true, and not concentrated as they are in the brain.' [Footnote:
Letter to Lange: 'Geschichte des Materialismus,' zweite Aufl,
vol. ii. p. 521.] We may not be able to taste or smell alcohol in a
tub of fermented cherries, but by distillation we obtain from them
concentrated Kirschwasser. Hence Ueberweg's comparison of the brain
to a still, which concentrates the sensation and feeling,
pre-existing, but diluted in the food.
'Definitions,' says Mr. Holyoake, [Footnote: 'Nineteenth Century,'
September 1878.] 'grow as the horizon of experience expands. They
are not inventions, but descriptions of the state of a question. No
man sees all through a discovery at once.' Thus Descartes's notion of
matter, and his explanation of motion, would be put aside as trivial
by a physiologist or a crystallographer of the present day. They are
not descriptions of the state of the question. And yet a desire
sometimes shows itself in distinguished quarters to bind us own to
conceptions which passed muster in the infancy of knowledge, but which
are wholly incompatible with our present enlightenment. Mr.
Martineau, I think, errs when he seeks to hold me to views enunciated
by 'Democritus and the mathematicians.' That definitions should change
as knowledge advances is in accordance both with sound sense and
scientific practice. When, for example, the undulatory theory was
started, it was not imagined that the vibrations of light could be
transverse to the direction of propagation. The example of sound was
at hand, which was a case of longitudinal vibration. Now the
substitution of transverse for longitudinal vibrations in the case of
light involved a radical change of conception as to the mechanical
properties of the luminiferous medium. But though this change went so
far as to fill space with a substance, possessing the properties of a
solid, rather than those of a gas, the change was accepted, because
the newly discovered facts imperatively demanded it. Following Mr.
Martineau's example, the opponent of the undulatory theory might
effectually twit the holder of it on his change of front. 'This
aether of yours,' he might say, 'alters its style with every change
of service. Starting as a beggar, with scarce a rag of 'property' to
cover its bones, it turns up as a prince when large undertakings are
wanted. You had some show of reason when, with the case of sound
before you, you assumed your aether to be a gas in the last extremity
of attenuation. But now that new service is rendered necessary by new
facts, you drop the beggar's rags, and accomplish an undertaking,
great and princely enough in all conscience; for it implies that not
only planets of enormous weight, but comets with hardly any weight at
all, fly through your hypothetical solid without perceptible loss of
motion.' This would sound very cogent, but it would be very vain.
Equally vain, in my opinion, is Mr. Martineau's contention that we are
not justified in modifying, in accordance with advancing knowledge,
our notions of matter.
Before parting from Professor Knight, let me commend his courage as
well as his insight. We have heard much of late of the peril to
morality involved in the decay of religious belief. What Mr. Knight
says under this head is worthy of all respect and attention. 'I
admit,' he writes, 'that were it proved that the moral faculty was
derived as well as developed, its present decisions would not be
invalidated. The child of experience has a father whose teachings are
grave, peremptory, and august; and an earthborn rule may be as
stringent as any derived from a celestial source. It does not even
follow that a belief in the material origin of spiritual existence,
accompanied by a corresponding decay of belief in immortality, must
necessarily lead to a relaxation of the moral fibre of the race.
[Footnote: Is this really certain? Instead of standing in the
relation of cause and effect, may not the 'decay' and 'relaxation' be
merely coexistent, both, perhaps, flowing from common historic
antecedents?] It is certain that it has often done so. But it is
equally certain that there have been individuals, and great historical
communities, in which the absence of the latter belief has neither
weakened moral earnestness, nor prevented devotional fervour.' I have
elsewhere stated that some of the best men of my acquaintance--men
lofty in thought and beneficent in act--belong to a class who
assiduously let the belief referred to alone. They derive from it
neither stimulus nor inspiration, while--I say it with regret--were I
in quest of persons who, in regard to the finer endowments of human
character, are to be ranked with the unendowed, I should find some
characteristic samples among the noisier defenders of the orthodox
belief. These, however, are but 'hand-specimens' on both sides; the
wider data referred to by Professor Knight constitute, therefore, a
welcome corroboration of my experience. Again, my excellent critic,
Professor Blackie, describes Buddha as being 'a great deal more than a
prophet; a rare, exceptional, and altogether transcendental
incarnation of moral perfection.' [Footnote: 'Natural History of
Atheism,' p. 136.] And yet, 'what Buddha preached was a gospel of
pure human ethics, divorced not only from Brahma and the Brahminic
Trinity, but even from the existence of God.' [Footnote: Natural
History of Atheism,' p. 125.] These civilised and gallant voices
from the North contrast pleasantly with the barbarous whoops which
sometimes come to us along the same meridian.
*****
Looking backwards from my present standpoint over the earnest past, a
boyhood fond of play and physical action, but averse to schoolwork,
lies before me. The aversion did not arise from intellectual apathy
or want of appetite for knowledge, but simply from the fact that my
earliest teachers lacked the power of imparting vitality to what they
taught. Athwart all play and amusement, however, a thread of
seriousness ran through my character; and many a sleepless night of my
childhood has been passed, fretted by the question 'Who made God?' I
was well versed in Scripture; for I loved the Bible, and was prompted
by that love to commit large portions of it to memory. Later on I
became adroit in turning my Scriptural knowledge against the Church of
Rome, but the characteristic doctrines of that Church marked only for
a time the limits of enquiry. The eternal Sonship of Christ, for
example, as enunciated in the Athanasian Creed, perplexed me. The
resurrection of the body was also a thorn in my mind, and here I
remember that a passage in Blair's 'Grave' gave me momentary rest.
Sure the same power
That rear'd the piece at first and took it down
Can reassemble the loose, scatter'd parts
And put them as they were.
The conclusion seemed for the moment entirely fair, but with further
thought, my difficulties came back to me. I had seen cows and sheep
browsing upon churchyard grass, which sprang from the decaying mould
of dead men. The flesh of these animals was undoubtedly a
modification of human flesh, and the persons who fed upon them were as
undoubtedly, in part, a more remote modification of the same
substance. I figured the self-same molecules as belonging first to
one body and afterwards to a different one, and I asked myself how two
bodies so related could possibly arrange their claims at the day of
resurrection. The scattered parts of each were to be reassembled and
set as they were. But if handed over to the one, how could they
possibly enter into the composition of the other? Omnipotence itself,
I concluded, could not reconcile the contradiction. Thus the plank
which Blair's mechanical theory of the resurrection brought
momentarily into sight, disappeared, and I was again cast abroad on
the waste ocean of speculation.
At the same time I could by no means get rid of the idea that the
aspects of nature and the consciousness of man implied the operation
of a power altogether beyond my grasp--an energy the thought of which
raised the temperature of the mind, though it refused to accept shape,
personal or otherwise, from the intellect. Perhaps the able critics
of the 'Saturday Review' are justified in speaking as they sometimes
do of Mr. Carlyle. They owe him nothing, and have a right to announce
the fact in their own way. I, however, owe him a great deal, and am
also in honour bound to acknowledge the debt. Few, perhaps, who are
privileged to come into contact with that illustrious man have shown
him a sturdier front than I have, or in discussing modern science have
more frequently withstood him. But I could see that his contention at
bottom always was that the human soul has claims and yearnings which
physical science cannot satisfy. England to come will assuredly thank
him for his affirmation of the ethical and ideal side of human nature.
Be this as it may, at the period now reached in my story the feeling
referred to was indefinitely strengthened, my whole life being at the
same time rendered more earnest, resolute, and laborious by the
writings of Carlyle. Others also ministered to this result. Emerson
kindled me, while Fichte powerfully stirred my moral pulse. [Footnote:
The reader will find in the Seventeenth Lecture of Fichte's course on
the 'Characteristics of the Present Age' a sample of the vital power
of this philosopher.] In this relation I cared little for political
theories or philosophic systems, but a great deal for the propagated
life and strength of pure and powerful minds. In my later
school-days, under a clever teacher, some knowledge of mathematics and
physics had been picked up: my stock of both was, however, scanty, and
I resolved to augment it. But it was really with the view of learning
whether mathematics and physics could help me in other spheres, rather
than with the desire of acquiring distinction in either science, that
I ventured, in 1848, to break the continuity of my life, and devote
the meagre funds then at my disposal to the study of science in
Germany.
But science soon fascinated me on its own account. To carry it duly
and honestly out, moral qualities were incessantly invoked. There was
no room allowed for insincerity--no room even for carelessness. The
edifice of science had been raised by men who had unswervingly
followed the truth as it is in nature; and in doing so had often
sacrificed interests which are usually potent in this world. Among
these rationalistic men of Germany I found conscientiousness in work
as much insisted on as it could be among theologians. And why, since
they had not the rewards or penalties of the theologian to offer to
their disciples? Because they assumed, and were justified in
assuming, that those whom they addressed had that within them which
would respond to their appeal. If Germany should ever change for
something less noble the simple earnestness and fidelity to duty,
which in those days characterised her teachers, and through them her
sons generally, it will not be because of rationalism. Such a
decadent Germany might coexist with the most rampant rationalism
without their standing to each other in the relation of cause and
effect.
My first really laborious investigation, conducted jointly with my
friend Professor Knoblauch, landed me in a region which harmonised
with my speculative tastes. It was essentially an enquiry in
molecular physics, having reference to the curious, and then
perplexing, phenomena exhibited by crystals when freely suspended in
the magnetic field. I here lived amid the most complex operations of
magnetism in its twofold aspect of an attractive and a repellent
force. Iron was attracted by a magnet, bismuth was repelled, and the
crystals operated on ranged themselves under these two heads. Faraday
and Pluecker had worked assiduously at the subject, and had invoked
the aid of new forces to account for the phenomena. It was soon,
however, found that the displacement in a crystal of an atom of the
iron class by an atom of the bismuth class, involving no change of
crystalline form, produced a complete reversal of the phenomena. The
lines through the crystal which were in the one case drawn towards the
poles of the magnet, were driven, in the other case, from these poles.
By such instances and the reasoning which they suggested,
magne-crystallic action was proved to be due, not to the operation of
new forces, but to the modification of the old ones by molecular
arrangement. Whether diamagnetism, like magnetism, was a polar force,
was in those days a subject of the most lively contention. It was
finally proved to be so; and the most complicated cases of
magne-crystallic action were immediately shown to be simple mechanical
consequences of the principle of diamagnetic polarity. These early
researches, which occupied in all five years of my life, and
throughout which the molecular architecture of crystals was an
incessant subject of mental contemplation, gave a tinge and bias to my
subsequent scientific thought, and their influence is easily traced in
my subsequent enquiries. For example, during nine years of labour on
the subject of radiation, heat and light were handled throughout by
me, not as ends, but as instruments by the aid of which the mind might
perchance lay hold upon the ultimate particles of matter.
Scientific progress depends mainly upon two factors which incessantly
interact--the strengthening of the mind by exercise, and the
illumination of phenomena by knowledge. There seems no limit to the
insight regarding physical processes which this interaction carries in
its train. Through such insight we are enabled to enter and explore
that subsensible world into which all natural phenomena strike their
roots, and from which they derive nutrition. By it we are enabled to
place before the mind's eye atoms and atomic motions which lie far
beyond the range of the senses, and to apply to them reasoning as
stringent as that applied by the mechanician to the motions and
collisions of sensible masses. But once committed to such
conceptions, there is a risk of being irresistibly led beyond the
bounds of inorganic nature. Even in those early stages of scientific
growth, I found myself more and more compelled to regard not only
crystals, but organic structures, the body of man inclusive, as cases
of molecular architecture, infinitely more complex, it is true, than
those of inorganic nature, but reducible, in the long run, to the same
mechanical laws. In ancient journals I find recorded ponderings and
speculations relating to these subjects, and attempts made, by
reference to magnetic and crystalline phenomena, to present some
satisfactory image to the mind of the way in which plants and animals
are built up. Perhaps I may be excused for noting a sample of these
early speculations, already possibly known to a few of my readers, but
which here finds a more suitable place than that which it formerly
occupied.
*****
Sitting, in the summer of 1855, with my friend Dr. Rebus under the
shadow of a massive elm on the bank of a river in Normandy, the
current of our thoughts and conversation was substantially this: We
regarded the tree above us. In opposition to gravity its molecules
had ascended, diverged into branches, and budded into innumerable
leaves. What caused them to do so--a power external to themselves, or
an inherent force? Science rejects the outside builder; let us,
therefore, consider from the other point of view the experience of the
present year. A low temperature had kept back for weeks the life of
the vegetable world. But at length the sun gained power--or, rather,
the cloud-screen which our atmosphere had drawn between him and us was
removed--and life immediately kindled under his warmth. But what is
life, and how can solar light and heat thus affect it? Near our elm
was a silver birch, with its leaves rapidly quivering in the morning
air. We had here motion, but not the motion of life. Each leaf moved
as a mass under the influence of an outside force, while the motion of
life was inherent and molecular. How are we to figure this molecular
motion--the forces which it implies, and the results which flow from
them? Suppose the leaves to be shaken from the tree and enabled to
attract and repel each other. To fix the ideas, suppose the point of
each leaf to repel all the other points and to attract the roots, and
the root of each leaf to repel all other roots, but to attract the
points. The leaves would then resemble an assemblage of little
magnets abandoned freely to the interaction of their own forces. In
obedience to these they would arrange themselves, and finally assume
positions of rest, forming a coherent mass. Let us suppose the
breeze, which now causes them to quiver, to disturb the assumed
equilibrium. As often as disturbed there would be a constant effort
on the part of the leaves to re-establish it; and in making this
effort the mass of leaves would pass through different shapes and
forms. If other leaves, moreover, were at hand endowed with similar
forces, the attraction would extend to them--a growth of the mass of
leaves being the consequence.
We have strong reason for assuming that the ultimate particles of
matter--the atoms and molecules of which it is made up--are endowed
with forces coarsely typified by those here ascribed to the leaves.
The phenomena of crystallisation load, of necessity, to this
conception of molecular polarity. Under the operation of such forces
the molecules of a seed, like our fallen leaves in the first instance,
take up positions from which they would never move if undisturbed by
an external impulse. But solar light and heat, which come to us as
waves through space, are the great agents of molecular disturbance. On
the inert molecules of seed and soil these waves impinge, disturbing
the atomic equilibrium, which there is an immediate effort to restore.
The effort, incessantly defeated--for the waves continue to pour
in--is incessantly renewed; in the molecular struggle matter is
gathered from the soil and from the atmosphere, and built, in
obedience to the forces which guide the molecules, into the special
form of the tree. In a general way, therefore, the life of the tree
might be defined as an unceasing effort to restore a disturbed
equilibrium. In the building of crystals Nature makes her first
structural effort; we have here the earliest groping of the so-called
'vital force,' and the manifestations of this force in plants and
animals, though, as already stated, indefinitely more complex, are to
be regarded of the same mechanical quality as those concerned in the
building of the crystal.
Consider the cycle of operations by which the seed produces the plant,
the plant the flower, the flower again the seed, the causal line,
returning with the fidelity of a planetary orbit to its original point
of departure. Who or what planned this molecular rhythm? We do not
know--science fails even to inform us whether it was ever 'planned' at
all. Yonder butterfly has a spot of orange on its wing; and if we
look at a drawing made a century ago, of one of the ancestors of that
butterfly, we probably find the selfsame spot upon the wing. For a
century the molecules have described their cycles. Butterflies have
been begotten, have been born, and have died; still we find the
molecular architecture unchanged. Who or what determined this
persistency of recurrence? We do not know; but we stand within our
intellectual range when we say that there is probably nothing in that
wing which may not yet find its Newton to prove that the principles
involved in its construction are qualitatively the same as those
brought into play in the formation of the solar system. We may even
take a step further, and affirm that the brain of man--the organ of
his reason--without which he can neither think nor feel, is also an
assemblage of molecules, acting and reacting according to law. Here,
however, the methods pursued in mechanical science come to an end; and
if asked to deduce from the physical interaction of the brain
molecules the least of the phenomena of sensation or thought, I
acknowledge my helplessness. The association of both with the matter
of the brain may be as certain as the association of light with the
rising of the sun. But whereas in the latter case we have unbroken
mechanical connection between the sun and our organs, in the former
case logical continuity disappears. Between molecular mechanics and
consciousness is interposed a fissure over which the ladder of
physical reasoning is incompetent to carry us. We must, therefore,
accept the observed association as an empirical fact, without being
able to bring it under the yoke of _à priori_ deduction.
*****
Such were the ponderings which ran habitually through my mind in the
days of my scientific youth. They illustrate two things--a
determination to push physical considerations to their utmost
legitimate limit; and an acknowledgment that physical considerations
do not lead to the final explanation of all that we feel and know.
This acknowledgment, be it said in passing, was by no means made with
the view of providing room for the play of considerations other than
physical. The same intellectual duality, if I may use the phrase,
manifests itself in the following extract from an article entitled
'Physics and Metaphysics,' published in the 'Saturday Review' for
August 4, 1860: