In a kindred spirit, though separated from Socrates by the whole result of that physical science which Socrates had deprecated, we find a great modern systematiser of human thought again endeavouring to direct the scientific impulse towards things serviceable to man; to divert it from things remote, unknowable, and useless if known. What then, in Comte’s view, are in fact the limits of man’s actual home and business? the bounds within which he may set himself to learn all he can, assured that all will serve to inform his conscience and guide his life? It is the solar system which has become for the French philosopher what the street and market-place of Athens were for the Greek. And this enlargement (it need hardly be said) is not due to any wider grasp of mind in Comte than in Socrates, but simply to the march of science; which has shown us that the whole solar system does, in fact, minister to our practical needs, and that the Nautical Almanack demands for its construction a mapping of the paths of those ordered luminaries which in the time of Socrates seemed the very wanderers of Heaven.
I need not say that Comte’s prohibition has been altogether neglected. No frontier of scientific demarcation has been established between Neptune and Sirius, between Uranus and Aldebaran. Our knowledge of the fixed stars increases yearly; and it would be rash to maintain that human conduct is not already influenced by the conception thus gained of the unity and immensity of the heavens.
To many of the comments that have been made on our work, even by men who are not formal Comtists, the above reflections furnish a fitting reply. But it is not only, nor perhaps mainly, on account of the remoteness of our subject, or its unimportance to human progress, that objection is taken to our inquiry. The criticisms which have met us, from the side sometimes of scientific, sometimes of religious orthodoxy, have embodied, in modernised phraseology, nearly every well-worn form of timid protest, or obscurantist demurrer, with which the historians of science have been accustomed to give piquancy to their long tale of discovery and achievement. It would have been convenient had these objections been presented to us in a connected and formal manner. But this has not been the case; and, in fact, they are in their very nature too incoherent, too self-contradictory, for continuous statement. Sometimes we are told that we are inviting the old theological spirit to encroach once more on the domain of science; sometimes that we are endeavouring to lay the impious hands of Science upon the mysteries of Religion. Sometimes we are informed that competent savants have already fully explored the field which we propose for our investigation; sometimes that no respectable man of science would condescend to meddle with such a reeking mass of fraud and hysteria. Sometimes we are pitied as laborious triflers who prove some infinitely small matter with mighty trouble and pains; sometimes we are derided as attempting the solution of gigantic problems by slight and superficial means.
§ 4. The best way of meeting objections thus confused and contradictory will be to show as clearly as we can at what points our inquiries touch the recent results of science; what signs there are which indicate the need of vigorous advance along the lines which we have chosen. We shall show, perhaps, that there is a kind of convergence towards this especial need—that in several directions of research there is felt that kind of pause and hesitancy which is wont to precede the dawn of illuminating conceptions. We shall not, of course, thus prove that our own attempt has been successful, but we shall prove that it was justified; that if the problems which we set ourselves to solve are found to be insoluble, the gaps thus left in the system of thought on which man’s normal life is based will be such as can neither be ignored nor supplied, but will become increasingly palpable and increasingly dangerous.
Let us consider how far this remark can be justified with regard to some of the leading branches of human knowledge in turn. And let us take first Biology, the science which on the whole approaches the closest to our own inquiries. Biology has, during the last half-century, made an advance which, measured by the hold exercised on the mass of cultivated minds, has perhaps had no parallel since the forward stride of astronomy and physics in the days of Newton. A glance at the text-books of the last generation, in physical or mental science—Whewell’s History of the Inductive Sciences, or Mill’s Logic,—as compared, for instance, with the works of their immediate successor, Mr. Herbert Spencer, shows something which is not so much progress as revolution—the transformation of Biology from a mere special department of knowledge into the key to man’s remotest history, the only valid answer to the profoundest questions as to his present being.
For, in truth, it is Biology above all other sciences which has profited by the doctrine of evolution. In evolution,—in the doctrine that the whole cosmical order is the outcome of a gradual development,—mankind have gained for the first time a working hypothesis which covers enough of the known facts of the universe to make its possible extension to all facts a matter of hopeful interest. And Biology, which even at the date of Whewell’s book could barely make good its claim to be regarded as a coherent science at all, has now acquired a co-ordinating and continuous principle of unity which renders it in some respects the best type of a true science which we possess. It traces life from the protozoon to the animal, from the brute to the man; it offers to explain the complex fabric of human thought and emotion, viewed from the physical side, as the development of the molecular movements of scarcely-differentiated fragments of protaplasm.
And along with this increased knowledge of the processes by which man has been upbuilt has come also an increased knowledge of the processes which are now going on within him. The same inquiries which have brought our organic life into intelligible relation with the whole range of animal and vegetable existence have enabled us also to conceive more definitely the neural side of our mental processes, and the relation of cerebral phenomena to their accompanying emotion or thought. And hence, in the view of some ardent physiologists, it is becoming more and more probable that we are in fact physiological automata; that our consciousness is a mere superadded phenomenon—a mere concomitant of some special intensity of cerebral action, with no basis beyond or apart from the molecular commotion of the brain.
But this view, as it would seem, depends in a great part upon something which corresponds in the mental field to a familiar optical illusion. When we see half of some body strongly illuminated, and half of it feebly illuminated, it is hard to believe that the brilliant moiety is not the larger of the two. And, similarly, it is the increased definiteness of our conception of the physical side of our mental operations which seems to increase its relative importance,—to give it a kind of priority over the psychical aspect of the same processes. Yet, of course, to the philosophic eye the central problem of the relation of the objective and subjective sides of these psycho-neural phenomena can be in no way altered by any increase of definiteness in our knowledge of the objective processes which correspond to the subjective states.
And, on the other hand, there is one singular logical corollary which seems thus far to have escaped the notice of physiologist and psychologist alike. It is this: that our increased vividness of conception of the physical side of mental life, while it cannot possibly disprove the independence of the psychical side, may quite conceivably prove it. I will again resort to the (very imperfect) analogy of a partially-illuminated body. Suppose that one hemisphere of a globe is strongly lit up, and that the other is lit up by faint and scattered rays.1 I am trying to discern whether the two hemispheres are symmetrically marked throughout. Now no clearness of marks on the bright hemisphere can disprove the existence of corresponding marks on the dim one. But, on the other hand, it is conceivable that one of the few rays which fall on the dim hemisphere may reveal some singular mark which I can see that the bright hemisphere does not possess. And the brighter the bright hemisphere is made, the more certain do I become that this particular mark is not to be found on it.
§ 5. I will give two concrete examples of what I mean—one of them drawn from the conclusions of a great physiologist, the other from the obvious condition of a new branch of experimental inquiry. I shall not discuss either instance in detail, since I am here only endeavouring to show that with increased precision in psychophysical researches the old problems of free-will, soul and body, &c., are presenting more definite issues, and offering a far more hopeful field to the exact philosopher than their former vagueness allowed.
My first illustration,