A Short History of Freethought Ancient and Modern, Volume 2 of 2 / Third edition, Revised and Expanded, in two volumes

by J. M. Robertson

Section 4.—The Natural Sciences

1. The power of intellectual habit and tradition had preserved among the majority of educated men, to the end of the eighteenth century, a notion of deity either slightly removed from that of the ancient Hebrews or ethically purified without being philosophically transformed, though the astronomy of Copernicus, Galileo, and Newton had immensely modified the Hebraic conception of the physical universe. We have seen that Newton did not really hold by the Christian scheme—he wrote, at times, in fact, as a pantheist—but some later astronomers seem to have done so. When, however, the great Laplace developed the nebular hypothesis, previously guessed at by Bruno and outlined by Kant, orthodox psychological habit was rudely shaken as regards the Biblical account of creation; and like every other previous advance in physical science this was denounced as atheistic[217]—which, as we know, it was, Laplace having declared in reply to Napoleon that he had no need of the God hypothesis. Confirmed in essentials by all subsequent science, Laplace’s system widens immensely the gulf between modern cosmology and the historic theism of the Christian era; and the subsequent concrete developments of astronomy, giving as they do such an insistent and overwhelming impression of physical infinity, have made the “Christian hypothesis”[218] fantastic save for minds capable of enduring any strain on the sense of consistency. Paine had brought the difficulty vividly home to the common intelligence; and though the history of orthodoxy is a history of the success of institutions and majorities in imposing incongruous conformities, the perception of the incongruity on this side must have been a force of disintegration. The freethinking of the French astronomers of the Revolution period marks a decisive change; and as early as 1826 we find in a work on Jewish antiquities by a Scotch clergyman a very plain indication[219] of disbelief in the Hebrew story of the stopping of the sun and moon, or (alternatively) of the rotation of the earth. It is typical of the tenacity of religious delusion that a quarter of a century later this among other irrational credences was contended for by the Swiss theologian Gaussen,[220] and by the orthodox majority elsewhere, when for all scientifically trained men they had become untenable. And that the general growth of scientific thought was disintegrating among scientific men the old belief in miracles may be gathered from an article, remarkable in its day, which appeared in the Edinburgh Review of January, 1814 (No. 46), and was “universally attributed to Prof. Leslie,”[221] the distinguished physicist. Reviewing the argument of Laplace’s essay, Sur les probabilités, it substantially endorsed the thesis of Hume that miracles cannot be proved by any testimony.

Leslie’s own case is one of the milestones marking the slow recovery of progress in Britain after the Revolution. His appointment to the chair of Mathematics, after Playfair, at Edinburgh University in 1805 was bitterly resisted by the orthodox on the score that he was a disbeliever in miracles and an “infidel” of the school of Hume, who had been his personal friend. Nevertheless he again succeeded Playfair in the chair of Physics in 1819, and was knighted in 1832. The invention of the hygrometer and the discovery of the relations of light and heat had begun to count for more in science than the profession of orthodoxy.

2. From France came likewise the impulse to a naturalistic handling of biology, long before the day of Darwin. The protagonist in this case was the physician P.-J.-G. Cabanis (1737–1808), the colleague of Laplace in the School of Sciences. Growing up in the generation of the Revolution, Cabanis had met, in the salon of Madame Helvétius, d’Holbach, Diderot, D’Alembert, Condorcet, Laplace, Condillac, Volney, Franklin, and Jefferson, and became the physician of Mirabeau. His treatise on the Rapports du physique et du morale de l’homme (1796–1802)[222] might be described as the systematic application to psychology of that “positive” method to which all the keenest thought of the eighteenth century had been tending, yet with much of the literary or rhetorical tone by which the French writers of that age had nearly all been characterized. For Cabanis, the psychology of Helvétius and Condillac had been hampered by their ignorance of physiology;[223] and he easily put aside the primary errors, such as the “equality of minds” and the entity of “the soul,” which they took over from previous thinkers. His own work is on the whole the most searching and original handling of the main problems of psycho-physiology that had yet been achieved; and to this day its suggestiveness has not been exhausted.

But Cabanis, in his turn, made the mistake of Helvétius and Condillac. Not content with presenting the results of his study in the province in which he was relatively master, he undertook to reach ultimate truth in those of ethics and philosophy, in which he was not so. In the preface to the Rapports he lays down an emphatically agnostic conviction as to final causes: “ignorance the most invincible,” he declares, is all that is possible to man on that issue.[224] But not only does he in his main work freely and loosely generalize on the phenomena of history and overleap the ethical problem: he penned shortly before his death a Lettre sur les causes premières, addressed to Fauriel,[225] in which the aging intelligence is seen reverting to à priori processes, and concluding in favour of a “sort of stoic pantheism”[226] with a balance towards normal theism and a belief in immortality. The final doctrine did not in the least affect the argument of the earlier, which was simply one of positive science; but the clerical world, which had in the usual fashion denounced the scientific doctrine, not on the score of any attack by Cabanis upon religion, but because of its incompatibility with the notion of the soul, naturally made much of the mystical,[227] and accorded its framer authority from that moment.

As for the conception of “vitalism” put forward in the Letter to Fauriel by way of explanation of the phenomena of life, it is but a reversion to the earlier doctrine of Stahl, of which Cabanis had been a partisan in his youth.[228] The fact remains that he gave an enduring impulse to positive science,[229] his own final vacillation failing to arrest the employment of the method he had inherited and improved. Most people know him solely through one misquotation, the famous phrase that “the brain secretes thought as the liver secretes bile.” This is not only an imperfect statement of his doctrine: it suppresses precisely the idea by which Cabanis differentiates from pure “sensationalism.” What he taught was that “impressions, reaching the brain, set it in activity, as aliments reaching the stomach excite it to a more abundant secretion of gastric juice.... The function proper to the first is to perceive particular impressions, to attach to them signs, to combine different impressions, to separate them, to draw from them judgments and determinations, as the function of the second is to act on nutritive substances,” etc.[230] It is after this statement of the known processus, and after pointing out that there is as much of pure inference in the one case as in the other, that he concludes: “The brain in a manner digests impressions, and makes organically the secretion of thought” and this conclusion, he points out, disposes of the difficulty of those who “cannot conceive how judging, reasoning, imagining, can ever be anything else than feeling. The difficulty ceases when one recognizes, in these different operations, the action of the brain upon the impressions which are passed on to it.” The doctrine is, in short, an elementary truth of psychological science, as distinguished from the pseudo-science of the Ego considered as an entity. To that pseudo-science Cabanis gave a vital wound; and his derided formula is for true science to-day almost a truism. The attacks made upon his doctrine in the next generation only served to emphasize anew the eternal dilemma of theism. On the one hand his final “vitalism” was repugnant to those who, on traditional lines, insisted upon a distinction between “soul” and “vital force”; on the other hand, those who sought to make a philosophic case for theism against him made the usual plunge into pantheism, and were reproached accordingly by the orthodox.[231] All that remained was the indisputable “positive” gain.

3. In England the influence of the French stimulus in physiology was seen even more clearly than that of the great generalization of Laplace. Professor William Lawrence (1783–1867), the physiologist, published in 1816 an Introduction to Comparative Anatomy and Physiology, containing some remarks on the nature of life, which elicited from the then famous Dr. Abernethy a foul attack in his Physiological Lectures delivered before the College of Surgeons. Lawrence was charged with belonging to the party of French physiological skeptics whose aim was to “loosen those restraints on which the welfare of mankind depends.”[232] In the introductory lecture of his course of 1817 before the College of Physicians, Lawrence severely retaliated, repudiating the general charge, but reasserting that the dependence of life on organization is as clear as the derivation of daylight from the sun. The war was adroitly carried at once into the enemy’s territory in the declaration that “The profound, the virtuous, and fervently pious Pascal acknowledged, what all sound theologians maintain, that the immortality of the soul, the great truths of religion, and the fundamental principles of morals cannot be demonstrably proved by mere reason; and that revelation alone is capable of dissipating the uncertainties which perplex those who inquire too curiously into the sources of these important principles. All will acknowledge that, as no other remedy can be so perfect and satisfactory as this, no other can be necessary, if we resort to this with firm faith.”[233] The value of this pronouncement is indicated later in the same volume by subacid allusions to “those who regard the Hebrew Scriptures as writings composed with the assistance of divine inspiration,” and who receive Genesis “as a narrative of actual events.” Indicating various “grounds of doubt respecting inspiration,” the lecturer adds that the stories of the naming of the animals and their collection in the ark, “if we are to understand them as applied to the living inhabitants of the whole world, are zoologically impossible.”[234] On the principle then governing such matters Lawrence was in 1822, on the score of his heresies, refused copyright in his lectures, which were accordingly reprinted many times in a cheap stereotyped edition, and thus widely diffused.[235]

This hardy attack was reinforced in 1819 by the publication of Sir T. C. Morgan’s Sketches of the Philosophy of Life, wherein the physiological materialism of Cabanis is quietly but firmly developed, and a typical sentence of his figures as a motto on the title-page. The method is strictly naturalistic, alike on the medical and on the philosophic side; and “vitalism” is argued down as explicitly as is anthropomorphism.[236] As a whole the book tells notably of the stimulus of recent French thought upon English.

4. A more general effect, however, was probably wrought by the science of geology, which in a stable and tested form belongs to the nineteenth century. Of its theoretic founders in the eighteenth century, Werner and Dr. James Hutton (1726–1797), the latter and more important[237] is known from his Investigation of the Principles of Knowledge (1794) to have been consciously a freethinker on more grounds than that of his naturalistic science; and his Theory of the World (1795) was duly denounced as atheistic.[238] Whereas the physical infinity of the universe almost forced the orthodox to concede a vast cosmic process of some kind as preceding the shaping of the earth and solar system, the formation of these within six days was one of the plainest assertions in the sacred books; and every system of geology excluded such a conception. As the evidence accumulated, in the hands of men mostly content to deprecate religious opposition,[239] there was duly evolved the quaint compromise of the doctrine that the Biblical six “days” meant six ages—a fantasy still cherished in the pulpit. On the ground of that absurdity, nevertheless, there gradually grew up a new conception of the antiquity of the earth. Thus a popular work on geology such as The Ancient World, by Prof. Ansted (1847), could begin with the proposition that “long before the human race had been introduced on the earth this world of ours existed as the habitation of living things different from those now inhabiting its surface.” Even the thesis of “six ages,” and others of the same order, drew upon their supporters angry charges of “infidelity.” Hugh Miller, whose natural gifts for geological research were chronically turned to confusion by his orthodox bias, was repeatedly so assailed, when in point of fact he was perpetually tampering with the facts to salve the Scriptures.[240] Of all the inductive sciences geology had been most retarded by the Christian canonization of error.[241] Even the plain fact that what is dry land had once been sea was obstinately distorted through centuries, though Ovid[242] had put the observations of Pythagoras in the way of all scholars; and though Leonardo da Vinci had insisted on the visible evidence; nay, deistic habit could keep even Voltaire, as we saw, preposterously incredulous on the subject. When the scientific truth began to force its way in the teeth of such authorities as Cuvier, who stood for the “Mosaic” doctrine, the effect was proportionately marked; and whether or not the suicide of Miller (1856) was in any way due to despair on perception of the collapse of his reconciliation of geology with Genesis,[243] the scientific demonstration made an end of revelationism for many. What helped most to save orthodoxy from humiliation on the scientific side was the attitude of men like Professor Baden Powell, whose scientific knowledge and habit of mind moved him to attack the Judaism of the Bibliolaters in the name of Christianity, and in the name of truth to declare that “nothing in geology bears the smallest semblance to any part of the Mosaic cosmogony, torture the interpretation to what extent we may.”[244] In 1857 this was very bold language.