Part 6

You see I am not mincing matters, but avowing nakedly what many scientific thinkers more or less distinctly believe. The formation of a crystal, a plant, or an animal, is in their eyes a purely mechanical problem, which differs from the problems of ordinary mechanics in the smallness of the masses and the complexity of the processes involved. Here you have one half of our dual truth; let us now glance at the other half. Associated with this wonderful mechanism of the animal body we have phenomena no less certain than those of physics, but between which and the mechanism we discern no necessary connexion. A man, for example, can say _I feel, I think, I love_; but how does _consciousness_ infuse itself into the problem? The human brain is said to be the organ of thought and feeling; when we are hurt the brain feels it, when we ponder it is the brain that thinks, when our passions or affections are excited it is through the instrumentality of the brain. Let us endeavour to be a little more precise here. I hardly imagine there exists a profound scientific thinker, who has reflected upon the subject, unwilling to admit the extreme probability of the hypothesis, that for every fact of consciousness, whether in the domain of sense, of thought, or of emotion, a certain definite molecular condition is set up in the brain; who does not hold this relation of physics to consciousness to be invariable, so that, given the state of the brain, the corresponding thought or feeling might be inferred; or given the thought or feeling, the corresponding state of the brain might be inferred.

But how inferred? It is at bottom not a case of logical inference at all, but of empirical association. You may reply that many of the inferences of science are of this character; the inference, for example, that an electric current of a given direction will deflect a magnetic needle in a definite way; but the cases differ in this, that the passage from the current to the needle, if not demonstrable, is thinkable, and that we entertain no doubt as to the final mechanical solution of the problem. But the passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a definite thought, and a definite molecular action in the brain occur simultaneously; we do not possess the intellectual organ, nor apparently any rudiment of the organ, which would enable us to pass, by a process of reasoning, from the one to the other. They appear together, but we do not know why. Were our minds and senses so expanded, strengthened, and illuminated as to enable us to see and feel the very molecules of the brain; were we capable of following all their motions, all their groupings, all their electric discharges, if such there be; and were we intimately acquainted with the corresponding states of thought and feeling, we should be as far as ever from the solution of the problem. ‘How are these physical processes connected with the facts of consciousness?’ The chasm between the two classes of phenomena would still remain intellectually impassable. Let the consciousness of _love_, for example, be associated with a right-handed spiral motion of the molecules of the brain, and the consciousness of _hate_ with a left-handed spiral motion. We should then know when we love that the motion is in one direction, and when we hate that the motion is in the other; but the ‘WHY?’ would remain as unanswerable as before.

In affirming that the growth of the body is mechanical, and that thought, as exercised by us, has its correlative in the physics of the brain, I think the position of the ‘Materialist’ is stated, as far as that position is a tenable one. I think the materialist will be able finally to maintain this position against all attacks; but I do not think, in the present condition of the human mind, that he can pass beyond this position. I do not think he is entitled to say that his molecular groupings and his molecular motions _explain_ everything. In reality they explain nothing. The utmost he can affirm is the association of two classes of phenomena, of whose real bond of union he is in absolute ignorance. The problem of the connexion of body and soul is as insoluble in its modern form as it was in the prescientific ages. Phosphorus is known to enter into the composition of the human brain, and a trenchant German writer has exclaimed, ‘Ohne Phosphor, kein Gedanke.’ That may or may not be the case; but even if we knew it to be the case, the knowledge would not lighten our darkness. On both sides of the zone here assigned to the materialist he is equally helpless. If you ask him whence is this ‘Matter’ of which we have been discoursing, who or what divided it into molecules, who or what impressed upon them this necessity of running into organic forms, he has no answer. Science is mute in reply to these questions. But if the materialist is confounded and science rendered dumb, who else is prepared with a solution? To whom has this arm of the Lord been revealed? Let us lower our heads and acknowledge our ignorance, priest and philosopher, one and all. Perhaps the mystery may resolve itself into knowledge at some future day. The process of things upon this earth has been one of amelioration. It is a long way from the Iguanodon and his contemporaries to the President and Members of the British Association. And whether we regard the improvement from the scientific or from the theological point of view, as the result of progressive development, or as the result of successive exhibitions of creative energy, neither view entitles us to assume that man’s present faculties end the series,--that the process of amelioration stops at him. A time may therefore come when this ultra-scientific region by which we are now enfolded may offer itself to terrestrial, if not to human investigation. Two-thirds of the rays emitted by the sun fail to arouse in the eye the sense of vision. The rays exist, but the visual organ requisite for their translation into light does not exist. And so from this region of darkness and mystery which surrounds us, rays may now be darting which require but the development of the proper intellectual organs to translate them into knowledge as far surpassing ours as ours surpasses that of the wallowing reptiles which once held possession of this planet. Meanwhile the mystery is not without its uses. It certainly may be made a power in the human soul; but it is a power which has feeling, not knowledge, for its base. It may be, and will be, and we hope is turned to account, both in steadying and strengthening the intellect, and in rescuing man from that littleness to which, in the struggle for existence, or for precedence in the world, he is continually prone.

EARLIER THOUGHTS.[8]

A WORK recently published by Mr. Murray contains a sketch of the grounds on which the most advanced scientific thinkers of the present day base their convictions as to the physical character of Light and Heat. The fundamental idea there developed is, that the phenomena of light and heat, like those of sound, are essentially _mechanical_. Precisely the same reasoning applies to the vibrating ether which produces the one as to the vibrating air which produces the other, and both are dealt with substantially as we should deal with the waves of a liquid or the swing of a pendulum. Reflection on this subject has suggested the thought that the considerations brought forward in the sketch referred to may apply themselves to certain phenomena which are usually considered to lie outside the pale of physics, and thus may indicate new relationships between man regarded as a being of intellect and emotion, and the wondrous material system in the midst of which he dwells.

All our intercourse with the external world consists exclusively in an interchange of motion. From a vibrating, sonorous body, for example, pulses are sent to the ear and stir the auditory nerve to motion. From a luminous body pulses are sent to the eye, and stir the optic nerve to motion. Other pulses of different periods strike upon other nerves, and produce the sensation of heat; but, in all cases, whether it be light, or sound, or ordinary feeling, the excitement of the nerves, regarded more strictly, is the excitement of motion. And if the motion be induced by internal causes instead of external, is it not fair to infer that the effect on consciousness will be the same? Let any nerve, for example, be thrown by morbid action into the precise state of motion which would be communicated to it by the pulses of a heated body, surely that nerve will declare itself hot--the mind will accept the subjective intimation exactly as if it were objective. The retina, as is well known, may be excited by purely mechanical means. A blow on the eye will cause a luminous flash, and the mere pressure of the finger on the external ball will produce a star of light, which Newton compared to the circles on a peacock’s tail. Disease makes people see visions and dream dreams; but, in all such cases, could we examine the organs implicated, we should, on philosophical grounds, expect to find them in that precise molecular condition which the real objects, if present, would superinduce.

The colour of light is determined by the frequency of the ethereal vibrations, as the pitch of sound is determined by the frequency of the aërial ones. The red or purple, for example, of a British maiden’s cheek and lips, the blue, violet, or brown of her eyes, have their strict physical equivalents in the lengths of the waves which issue from them; and these waves are not only as truly mechanical as the waves of the sea, but they are capable of having their mechanical value expressed in numbers. In the work already referred to, a chapter is devoted to the relation which subsists between light and heat and mere mechanical work. In virtue of this relation we can tell the precise amount of work which a given amount of sunshine can perform. Now, the hue of the cheek is caused by the extinction of certain of the solar rays by the colouring matter of the cheek, the residual colour being that seen. Could we interpose the substance to which some English cheeks owe their bloom in the path of a beam passing through a prism, we should probably find the orange and yellow and green of the prismatic spectrum more or less absorbed, the red and a portion of the blue being transmitted. This would give us a purplish blush resembling that of the permanganate of potash, commonly called the mineral chameleon, a solution of which acts upon the spectrum in the manner just described. Inasmuch, then, as we can calculate with perfect exactness the mechanical value of the total light which falls upon the epidermis, a certain fraction of this will express the mechanical value of the cheek’s colour. We do not therefore jest, but speak the words of truth and soberness when we affirm that the rays to which the tinting of any given cheek is due would, if mechanically applied, be competent to move a wheelbarrow through a certain space, or to lift a scuttle of coals to a certain calculable elevation.

But the human face and eyes flush at times with a radiance which might well be taken for a direct spiritual emanation entirely independent of ‘brute matter.’ Let us examine this point a little. Musical instruments, and also the human voice, have a peculiarity as regards their sounds which differs from mere pitch. A clarionet and a violin, for example, may be both pitched to the same note, but a listener who sees neither can at once tell that the _qualities_ of the notes are different. This difference is what the French call _timbre_, and the Germans, we believe, _Klang_. So, also, we can distinguish one vowel from another, though all may have the same pitch. The difference here, according to the recent investigations of Helmholtz, is due to the fact that certain incidental notes commingle in each case with the principal one, and produce a composite result. The ‘harmonics’ of a string are known to be due to minor vibrations which superpose themselves upon the principal ones, as small ripples cover parasitically the surfaces of large sea-waves. The notes of the true simple wave and of its parasites are heard at once, and it is the variation of the latter which produces differences in the _timbre_ of a musical instrument or of the human voice.

In speculating on those more subtle phases of expression to which we have above referred, might we not offer the conjecture that they are not due to those waves alone which make the eyes violet or give the cheek its rose, but are a result produced by the compounding of these with incidental waves, which influence the colour as the harmonic waves of sound influence the pure quality of a note? We have often watched with deep interest and sympathy the countenances of some of the praying women in the churches of the Continent. We have seen a penitent kneeling at a distance from the shrine of the Virgin, as if afraid to come nearer. Suddenly a glow has overspread her countenance, strengthening in radiance, till at length her very soul seemed shining through her features. Sure of her acceptance, she has confidently advanced, fallen prostrate immediately in front of the image, and remained therefor a time in silent ecstasy. We have watched the ebbing of the spiritual tide, and remarked the felicitous repose which it left behind. At each new phase of emotion the _timbre_ of this woman’s countenance changed, and

The music breathing from her face

became altered in quality.

The tendency of the above remarks is to show that the most subtle phases of ‘expression’ have at least a proximate mechanical origin. The splendours of the ‘imperial Eleänore’--the ‘languors of her love deep eyes’--are all reducible to the same cause; and not only so, but they actually exist for a time in space, isolated alike from her and her worshipper. Every gleam of those eyes, every flush of her brows, every motion of her lips requires the ether for its transmission, and a certain calculable time to pass from her to him. During this time, the expression which is to stir the soul, to kindle love or quench it, exists in space as a purely mechanical affection of matter; and, for aught we know, a slight steepness in the front of an ethereal billow, a slight curl of its crest, or some other accident of form, may determine whether the recipient of its shock is to be elated with joy or steeped in misery.

The philosophy of the future will assuredly take more account than that of the past of the relation of thought and feeling to physical processes; and it may be that the qualities of the mind will be studied through the organism as we now study the character of a force through the affections of ordinary matter. We believe that every thought and every feeling has its definite mechanical correlative--that it is accompanied by a certain separation and remarshalling of the atoms of the brain. This latter process is purely physical; and were the faculties we now possess sufficiently strengthened, without the creation of any new faculty, it would doubtless be within the range of our augmented powers to infer from the molecular state of the brain the character of the thought acting on it, and conversely to infer from the thought the exact molecular condition of the brain. We do not say--and this, as will be seen, is all-important--that the inference here referred to would be an _à priori_ one. But by observing, with the faculties we assume, the state of the brain and the associated mental affections, both might be so tabulated side by side that, if one were given, a mere reference to the table would declare the other. Our present powers, it is true, shrivel into nothingness when brought to bear on such a problem, but it is because of its complexity and our limits that this is the case. The _quality_ of the problem and the _quality_ of our powers are, we believe, so related, that a mere expansion of the latter would enable them to cope with the former. Why, then, in scientific speculation should we turn our eyes exclusively to the humble past? May it not be that a time is coming--ages no doubt distant, but still advancing--when the dwellers upon earth, starting from the gross human brain of to-day as a rudiment, may be able to apply to these mighty questions faculties of commensurate extent? Given the requisite expansibility to the present senses and intelligence of man--given also the time necessary for their expansion--and this high goal may be attained. Development is all that is required, and not a change of quality. There need be no absolute breach of continuity between us and our loftier brothers yet to come.

We have guarded ourselves against saying that the inferring of thought from material combinations and arrangements would be an inference _à priori_. The inference meant would be the same in kind as that which the observation of the effects of food and drink upon the mind would enable us to make, differing only from the latter in the degree of analytical insight which we suppose attained. Given the masses and distances of the planets, we can infer the perturbations consequent on their mutual attractions. Given the nature of a disturbance in water, air, or ether--from the physical qualities of the medium we can infer how its particles will be affected. Here the mind runs with certainty along the line of thought which connects the phenomena, and from beginning to end finds no break in the chain. But when we endeavour to pass by a similar process from the phenomena of physics to those of thought, we meet a problem which transcends any conceivable expansion of the powers which we now possess. We may think over the subject again and again, but it eludes all intellectual presentation. We stand at length face to face with the Incomprehensible. The territory of physics is wide, but it has its limits from which we look with vacant gaze into the region beyond. Whence come we; whither go we? The question dies without an answer--without even an echo--upon the infinite shores of the Unknown. Let us follow matter to its utmost bounds; let us claim it in all its forms to experiment with and to speculate upon. Casting the term ‘vital force’ from our vocabulary, let us reduce, if we can, the visible phenomena of life to mechanical attractions and repulsions. Having thus exhausted physics, and reached its very rim, the real mystery still looms beyond us. We have, in fact, made no step towards its solution. And thus it will ever loom--ever beyond the bourne of knowledge--compelling the philosophies of successive ages to confess that

We are such stuff As dreams are made of, and our little life Is rounded with a sleep.

FOOTNOTES:

[Footnote 1: One of my critics remarks, that he does not see the wit of calling Goethe’s ‘Farbenlehre’ and Bain’s ‘Logic,’ ‘two volumes of poetry.’ Nor do I.]

[Footnote 2: Induction, page 422.]

[Footnote 3: This glass, by reflected light, had a colour ‘strongly resembling that of a decoction of horse-chestnut bark.’ Curiously enough Goethe refers to this very decoction:--‘Man nehme einen Streifen frischer Rinde von der Rosskastanie, man stecke denselben in ein Glas Wasser, und in der kürzesten Zeit werden wir das vollkommenste Himmelblau entstehen sehen.’--Goethe’s _Werke_, b. xxix. p. 24.]

[Footnote 4: A resolute scrutiny of the experiments, recently executed with reference to this question, is sure to yield instructive results.]

[Footnote 5: Sir William Thomson.]

[Footnote 6: In the ‘Prefatory Letter’ to his ‘Lay Sermons,’ Mr. Huxley speaks of ‘microscopists, ignorant alike of Philosophy and Biology.’ With reference to one conspicuous member of this class, a doctor of medicine, lately professor in a London college famous for its orthodoxy, both Mr. Huxley and myself have long practised, and shall, I trust, continue to practise, the tolerance recommended above.]

[Footnote 7: An Address to the Mathematical and Physical Section of the British Association assembled at Norwich on August 19, 1868.]

[Footnote 8: From an article headed ‘Physics and Metaphysics,’ in the _Saturday Review_ for August 4, 1860.]

LONDON: PRINTED BY SPOTTISWOODE AND CO., NEW-STREET SQUARE AND PARLIAMENT STREET

=TRANSCRIBER’S NOTES=

Obvious typographical errors have been silently corrected.

Punctuation, hyphenation, and spelling were made consistent when a predominant preference was found in the original book; otherwise they were not changed.