internal heat, the animal organism can generate heat external to
itself. A blacksmith by hammering can warm a nail, and a savage by
friction can heat wood to its point of ignition. Unless, then, we
abandon the physiological axiom that the animal body cannot create
heat out of nothing, we are driven to the conclusion that it is the
total heat, within and without, that ought to be regarded as the real
calorific effect of the oxidation within the body.' Mayer, however,
not only states the principle, but illustrates numerically the
transfer of muscular heat to external space. A bowler who imparts a
velocity of 30 feet to an 8-lb. ball consumes in the act 0.1 of a
grain of carbon. The heat of the muscle is here distributed over the
track of the ball, being developed there by mechanical friction. A
man weighing 150 lbs. consumes in lifting his own body to a height of
8 feet the heat of a grain of carbon. Jumping from this height the
heat is restored. The consumption of 2 oz. 4 drs. 20 grs. of carbon
would place the same man on the summit of a mountain 10,000 feet high.
In descending the mountain an amount of heat equal to that produced by
the combustion of the foregoing amount of carbon is restored. The
muscles of a labourer whose weight is 150 lbs. weigh 64 lbs. When
dried they are reduced to 15 lbs. Were the oxidation corresponding to
a day-labourer's ordinary work exerted on the muscles alone, they
would be wholly consumed in 80 days. Were the oxidation necessary to
sustain the heart's action concentrated on the heart itself, it would
be consumed in 8 days. And if we confine our attention to the two
ventricles, their action would consume the associated muscular tissue
in 31 days. With a fulness and precision of which this is but a
sample did Mayer, between 1842 and, 1845, deal with the great question
of vital dynamics.
In direct opposition, moreover, to the foremost scientific authorities
of that day, with Liebig at their head, this solitary Heilbronn worker
was led by his calculations to maintain that the muscles, in the main,
played the part of machinery, converting the fat, which had been
previously considered a mere heat-producer, into the motive power of
the organism. Mayer's prevision has been justified by events, for the
scientific world is now upon his side.
We place, then, food in our stomachs as so much combustible matter. It
is first dissolved by purely chemical processes, and the nutritive
fluid is poured into the blood. Here it comes into contact with
atmospheric oxygen admitted by the lungs. It unites with the oxygen
as wood or coal might unite with it in a furnace. The matter-products
of the union, if I may use the term, are the same in both cases, viz.
carbonic acid and water. The force-products are also the same--heat
within the body, or heat and work outside the body. Thus far every
action of the organism belongs to the domain either of physics or of
chemistry. But you saw me contract the muscle of my arm. What
enabled me to do, so? Was it or was it not the direct action of my
will? The answer is, the action of the will is mediate, not direct.
Over and above the muscles the human organism is provided with long
whitish filaments of medullary matter, which issue from the spinal
column, being connected by it on the one side with the brain, and on
the other side losing themselves in the muscles. Those filaments or
cords are the nerves, which you know are divided into two kinds,
sensor and motor, or, if you like the terms better, afferent and
efferent nerves. The former carry impressions from the external world
to the brain; the latter convey the behests of the brain to the
muscles. Here, as elsewhere, we find ourselves aided by the sagacity
of Mayer, who was the first clearly to formulate the part played by
the nerves in the organism. Mayer saw that neither nerves nor brain,
nor both together, possessed the energy necessary to animal motion;
but he also saw that the nerve could lift a latch and open a door, by
which floods of energy are let loose. 'As an engineer,' he says with
admirable lucidity, 'by the motion of his finger in opening a valve or
loosening a detent can liberate an amount of mechanical energy almost
infinite compared with its exciting cause; so the nerves, acting on
the muscles, can unlock an amount of power out of all proportion to
the work done by the nerves themselves.' The nerves, according to
Mayer, pull the trigger, but the gunpowder which they ignite is stored
in the muscles. This is the view now universally entertained.
The quickness of thought has passed into a proverb, and the notion
that any measurable time elapsed between the infliction of a wound and
the feeling of the injury would have been rejected as preposterous
thirty years ago. Nervous impressions, notwithstanding the results of
Haller, were thought to be transmitted, if not instantaneously, at all
events with the rapidity of electricity. Hence, when Helmholtz, in
1851, affirmed, as the result of experiment, nervous transmission to
be a comparatively sluggish process, very few believed him. His
experiments may now be made in the lecture-room.
Sound in air moves at the rate of 1,100 feet a second; sound in water
moves at the rate of 5,000 feet a second; light in aether moves at the
rate of 186,000 miles a second, and electricity in free wires moves
probably at the same rate. But the nerves transmit their messages at
the rate of only 70 feet a second, a progress which in these quick
times might well be regarded as inordinately slow.
Your townsman, Mr. Gore, has produced by electrolysis a kind of
antimony which exhibits an action strikingly analogous to that of
nervous propagation. A rod of this antimony is in such a molecular
condition that when you scratch or heat one end of the rod, the
disturbance propagates itself before your eyes to the other end, the
onward march of the disturbance being announced by the development of
heat and fumes along the line of propagation. In some such way the
molecules of the nerves are successively overthrown; and if Mr. Gore
could only devise some means of winding up his exhausted antimony, as
the nutritive blood winds up exhausted nerves, the comparison would be
complete. The subject may be summed up, as Du Bois-Reymond has summed
it up, by reference to the case of a whale struck by a harpoon in the
tail. If the animal were 70 feet long, a second would elapse before
the disturbance could reach the brain. But the impression after its
arrival has to diffuse itself and throw the brain into the molecular
condition necessary to consciousness. Then, and not till then, the
command to the tail to defend itself is shot through the motor nerves.
Another second must elapse before the command can reach the tail, so
that more than two seconds transpire between the infliction of the
wound and the muscular response of the part wounded. The interval
required for the kindling of consciousness would probably more than
suffice for the destruction of the brain by lightning, or even by a
rifle-bullet. Before the organ can arrange itself it may, therefore,
be destroyed, and in such a case we may safely conclude that death is
painless.
*****
The experiences of common life supply us with copious instances of the
liberation of vast stores of muscular power by an infinitesimal
'priming' of the muscles by the nerves. We all know the effect
produced on a 'nervous' organisation by a slight sound which causes
affright. An aërial wave, the energy of which would not reach a
minute fraction of that necessary to raise the thousandth of a grain
through the thousandth of an inch, can throw the whole human frame
into a powerful mechanical spasm, followed by violent respiration and
palpitation. The eye of course, may be appealed to as well as the
ear. Of this the lamented Lange gives the following vivid
illustration:
A merchant sits complacently in his easy chair, not knowing whether
smoking, sleeping, newspaper reading, or the digestion of food
occupies the largest portion of his personality. A servant enters the
room with a telegram bearing the words, 'Antwerp, &c... Jonas
and Co. have failed.' 'Tell James to harness the horses!' The servant
flies. Upstairs the merchant, wide awake; makes a dozen paces through
the room, descends to the counting-house, dictates letters, and
forwards despatches. He jumps into his carriage, the horses snort,
and their driver is immediately at the Bank, on the Bourse, and among
his commercial friends. Before an hour has elapsed he is again at
home, where he throws himself once more into his easy chair with a
deep-drawn sigh, 'Thank God I am protected against the worst, and now
for further reflection.'
This complex mass of action, emotional, intellectual, and mechanical,
is evoked by the impact upon the retina of the infinitesimal waves of
light coming from a few pencil marks on a bit of paper. We have, as
Lange says, terror, hope, sensation, calculation, possible ruin, and
victory compressed into a moment. What caused the merchant to spring
out of his chair? The contraction of his muscles. What made his
muscles contract? An impulse of the nerves, which lifted the proper
latch, and liberated the muscular power. Whence this impulse? From
the centre of the nervous system. But how did it originate there?
This is the critical question, to which some will reply that it had
its origin in the human soul.
The aim and effort of science is to explain the unknown in terms of
the known. Explanation, therefore, is conditioned by knowledge. You
have probably heard the story of the German peasant, who, in early
railway days, was taken to see the performance of a locomotive. He
had never known carriages to be moved except by animal power. Every
explanation outside of this conception lay beyond his experience, and
could not be invoked. After long reflection therefore, and seeing no
possible escape from the conclusion, he exclaimed confidently to his
companion, 'Es muessen doch Pferde darin sein '--There must be horses
inside. Amusing as this locomotive theory may seem, it illustrates a
deep-lying truth.
With reference to our present question, some may be disposed to press
upon me such considerations as these: Your motor nerves are so many
speaking-tubes, through which messages are sent from the man to the
world; and your sensor nerves are so many conduits through which the
whispers of the world are sent back to the man. But you have not told
us where is the man. Who or what is it that sends and receives those
messages through the bodily organism? Do not the phenomena point to
the existence of a self within the self, which acts through the body
as through a skilfully constructed instrument? You picture the
muscles as hearkening to the commands sent through the motor nerves,
and you picture the sensor nerves as the vehicles of incoming
intelligence; are you not bound to supplement this mechanism by the
assumption of an entity which uses it? In other words, are you not
forced by Tour own exposition into the hypothesis of a free human
soul?
This is fair reasoning now, and at a certain stage of the world's
knowledge, it might well have been deemed conclusive. Adequate
reflection, however, shows that instead of introducing light into our
minds, this hypothesis considered scientifically increases our
darkness. You do not in this case explain the unknown in terms of the
known, which, as stated above, is the method of science, but you
explain the unknown in terms of the more unknown. Try to mentally
visualise this soul as an entity distinct from the body, and the
difficulty immediately appears. From the side of science all that we
are warranted in stating is that the terror, hope, sensation, and
calculation of Lange's merchant, are psychical phenomena produced by,
or associated with, the molecular processes set up by waves of light
in a previously prepared brain.
When facts present themselves let us dare to face them, but let the
man of science equally dare to confess ignorance where it prevails.
What then is the causal connection, if any, between the objective and
subjective--between molecular motions and states of consciousness? My
answer is: I do not see the connection, nor have I as yet met anybody
who does.
It is no explanation to say that the objective and subjective effects
are two sides of one and the same phenomenon. Why should the
phenomenon have two sides? This is the very core of the difficulty.
There are plenty of molecular motions which do not exhibit this
two-sidedness. Does water think or feel when it runs into frost-ferns
upon a window-pane? If not, why should the molecular motion of the
brain be yoked to this mysterious companion--consciousness? We can
form a coherent picture of the physical processes--the stirring of the
brain, the thrilling of the nerves, the discharging of the muscles,
and all the subsequent mechanical motions of the organism. But we can
present to our minds no picture of the process whereby consciousness
emerges, either as a necessary link or as an accidental by-product of
this series of actions. Yet it certainly does emerge--the prick of a
pin suffices to prove that molecular motion can produce consciousness.
The reverse process of the production of motion by consciousness is
equally unpresentable to the mind. We are here, in fact, upon the
boundary line of the intellect, where the ordinary canons of science
fail to extricate us from our difficulties. If we are true to these
canons, we must deny to subjective phenomena all influence on physical
processes. Observation proves that they interact, but in passing from
one to the other, we meet a blank which mechanical deduction is unable
to fill. Frankly stated, we have here to deal with facts almost as
difficult to seize mentally as the idea of a soul. And if you are
content to make your 'soul' a poetic rendering of a phenomenon which
refuses the yoke of ordinary physical laws, I, for one, would not
object to this exercise of ideality. Amid all our speculative
uncertainty, however, there is one practical point as clear as the
day; namely, that the brightness and the usefulness of life, as well
as its darkness and disaster, depend to a great extent upon our own
use or abuse of this miraculous organ.
Accustomed as I am to harsh language, I am quite prepared to hear my
'poetic rendering' branded as a 'falsehood' and a 'fib.' The
vituperation is unmerited, for poetry or ideality, and untruth are
assuredly very different things. The one may vivify, while the other,
kills. When St. John extends the notion of a soul to 'souls washed
in the blood of Christ' does he 'fib'? Indeed, if the appeal to
ideality is censurable, Christ himself ought not to have escaped
censure. Nor did he escape it. 'How can this man give us his flesh to
eat?' expressed the sceptical flouting of unpoetic natures. Such are
still amongst us. Cardinal Manning would doubtless tell any
Protestant who rejects the doctrine of transubstantiation that he
'fibs' away the plain words of his Saviour when he reduces 'the Body
of the Lord' in the sacrament to a mere figure of speech.
Though misuse may render it grotesque or insincere, the idealisation
of ancient conceptions, when done consciously and above board, has, in
my opinion, an important future. We are not radically different from
our historic ancestors, and any feeling which affected them
profoundly, requires only appropriate clothing to affect us. The
world will not lightly relinquish its heritage of poetic feeling, and
metaphysic will be welcomed when it abandons its pretensions to
scientific discovery and consents to be ranked as a kind of poetry. 'A
good symbol,' says Emerson, 'is a missionary to persuade thousands.
The Vedas, the Edda, the Koran, are each remembered by its happiest
figure. There is no more welcome gift to men than a new symbol. They
assimilate themselves to it, deal with it in all ways, and it will
last a hundred years. Then comes a new genius and brings another.'
Our ideas of God and the soul are obviously subject to this symbolic
mutation. They are not now what they were a century ago. They will
not be a century hence what they are now. Such ideas constitute a
kind of central energy in the human mind, capable, like the energy of
the physical universe, of assuming various shapes and undergoing
various transformations. They baffle and elude the theological
mechanic who would carve them to dogmatic forms. They offer
themselves freely to the poet who understands his vocation, and whose
function is, or ought to be, to find 'local habitation' for thoughts
woven into our subjective life, but which refuse to be mechanically
defined.
*****
We now stand face to face with the final problem. It is this: Are the
brain, and the moral and intellectual processes known to be associated
with the brain--and, as far as our experience goes, indissolubly
associated--subject to the laws which we find paramount in physical
nature? Is the will of man, in other words, free, or are it and
nature equally 'bound fast in fate'? From this latter conclusion,
after he had established it to the entire satisfaction of his
understanding, the great German thinker Fichte recoiled. You will
find the record of this struggle between head and heart in his book,
entitled 'Die Bestimmung des Menschen'--The Vocation of Man.
[Footnote: Translated by Dr. William Smith of Edinburgh; Truebner,
1873.] Fichte was determined at all hazards to maintain his freedom,
but the price he paid for it indicates the difficulty of the task. To
escape from the iron necessity seen everywhere reigning in physical
nature, he turned defiantly round upon nature and law, and affirmed
both of them to be the products of his own mind. He was not going to
be the slave of a thing which he had himself created. There is a good
deal to be said in favour of this view, but few of us probably would
be able to bring into play the solvent transcendentalism whereby
Fichte melted his chains.
Why do some regard this notion of necessity with terror, while others
do not fear it at all? Has not Carlyle somewhere said that a belief
in destiny is the bias of all earnest minds? 'It is not Nature,' says
Fichte, 'it is Freedom itself, by which the greatest and most
terrible disorders incident to our race are produced. Man is the
cruellest enemy of man.' But the question of moral responsibility here
emerges, and it is the possible loosening of this responsibility that
so many of us dread. The notion of necessity certainly failed to
frighten Bishop Butler. He thought it untrue even absurd--but he did
not fear its practical consequences. He showed, on the contrary, in
the 'Analogy,' that as far as human conduct is concerned, the two
theories of free-will and necessity would come to the same in the end.
What is meant by free-will? Does it imply the power of producing
events without antecedents?--of starting, as it were, upon a creative
tour of occurrences without any impulse from within or from without?
Let us consider the point. If there be absolutely or relatively no
reason why a tree should fall, it will not fall; and if there be
absolutely or relatively no reason why a man should act, he will not
act. It is true that the united voice of this assembly could not
persuade me that I have not, at this moment, the power to lift my arm
if I wished to do so. Within this range the conscious freedom of my
will cannot be questioned. But what about the origin of the 'wish'?
Are we, or are we not, complete masters of the circumstances which
create our wishes, motives, and tendencies to action? Adequate
reflection will, I think, prove that we are not. What, for example,
have I had to do with the generation and development of that which
some will consider my total being, and others a most potent factor of
my total being--the living, speaking organism which now addresses you?
As stated at the beginning of this discourse, my physical and
intellectual textures were woven for me, not by me. Processes in the
conduct or regulation of which I had no share have made me what I am.
Here, surely, if anywhere, we are as clay in the hands of the potter.
It is the greatest of delusions to suppose that we come into this
world as sheets of white paper on which the age can write anything it
likes, making us good or bad, noble or mean, as the age pleases. The
age can stunt, promote, or pervert pre-existent capacities, but it
cannot create them. The worthy Robert Owen, who saw in external
circumstances the great moulders of human character, was obliged to
supplement his doctrine by making the man himself one of the
circumstances. It is as fatal as it is cowardly to blink facts
because they are not to our taste. How many disorders, ghostly and
bodily, are transmitted to us by inheritance? In our courts of law,
whenever it is a question whether a crime has been committed under the
influence of insanity, the best guidance the judge and jury can have
is derived from the parental antecedents of the accused. If among
these insanity be exhibited in any marked degree, the presumption in
the prisoner's favour is enormously enhanced, because the experience
of life has taught both judge and jury that insanity is frequently
transmitted from parent to child.
I met, some years ago, in a railway carriage the governor of one of
our largest prisons. He was evidently an observant and reflective
man, possessed of wide experience gathered in various parts of the
world, and a thorough student of the duties of his vocation. He told
me that the prisoners in his charge might be divided into three
distinct classes. The first class consisted of persons who ought
never to have been in prison. External accident, and not internal
taint, had brought them within the grasp of the law, and what had
happened to them might happen to most of us. They were essentially
men of sound moral stamina, though wearing the prison garb. Then came
the largest class, formed of individuals possessing no strong bias,
moral or immoral, plastic to the touch of circumstances, which could
mould them into either good or evil members of society. Thirdly came
a class--happily not a large one--whom no kindness could conciliate
and no discipline tame. They were sent into this world labelled
'incorrigible', wickedness being stamped, as it were, upon their
organisations. It was an unpleasant truth, but as a truth it ought to
be faced. For such criminals the prison over which he ruled was
certainly not the proper place. If confined at all, their prison
should be on a desert island where the deadly _contagium_ of their
example could not taint the moral air. But the sea itself he was
disposed to regard as a cheap and appropriate substitute for the
island. It seemed to him evident that the State would benefit if
prisoners of the first class were liberated; prisoners of the second
class educated; and prisoners of the third class put compendiously
under water.
It is not, however, from the observation of individuals that the
argument against 'free-will,' as commonly understood, derives its
principal force. It is, as already hinted, indefinitely strengthened
when extended to the race. Most of you have been forced to listen to
the outcries and denunciations which rang discordant through the land
for some years after the publication of Mr. Darwin's 'Origin of
Species.' Well, the world--even the clerical world--for the most part
settled down in the belief that Mr. Darwin's book simply reflects the
truth of nature: that we who are now 'foremost in the files of time'
have come to the front through almost endless stages of promotion from
lower to higher forms of life.
If to any one of us were given the privilege of looking back through
the aeons across which life has crept towards its present outcome, his
vision, according to Darwin, would ultimately reach a point when the
progenitors of this assembly could not be called human. From that
humble society, through the interaction of its members and the storing
up of their best qualities, a better one emerged; from this again a
better still; until at length, by the integration of infinitesimals
through ages of amelioration, we came to be what we are to-day. We of
this generation had no conscious share in the production of this grand
and beneficent result. Any and every generation which preceded us had
just as little share. The favoured organisms whose garnered
excellence constitutes our present store owed their advantages, first,
to what we in our ignorance are obliged to call accidental variation;'
and, secondly, to a law of heredity in the passing of which our
suffrages were not collected. With characteristic felicity and
precision Mr. Matthew Arnold lifts this question into the free air of
poetry, but not out of the atmosphere of truth, when he ascribes the
process of amelioration to 'a power not ourselves which makes for
righteousness.' If, then, our organisms, with all their tendencies
and capacities, are given to us without our being consulted; and if,
while capable of acting within certain limits in accordance with our
wishes, we are not masters of the circumstances in which motives and
wishes originate; if, finally, our motives and wishes determine our
actions--in what sense can these actions be said to be the result of
free-will?
*****