Diderot and the Encyclopaedists Volume II Part 13

Maupertuis had in 1751, under the a.s.sumed name of Baumann, an imaginary doctor of Erlangen, published a dissertation on the _Universal System of Nature_, in which he seems to have maintained that the mechanism of the universe is one and the same throughout, modifying itself, or being modified by some vital element within, in an infinity of diverse ways.[207] Leibnitz's famous idea, of making nature invariably work with the minimum of action, was seized by Maupertuis, expressed as the Law of Thrift, and made the starting-point of speculations that led directly to Holbach and the _System of Nature_.[208] The _Loi d'Epargne_ evidently tended to make unity of all the forces of the universe the keynote or the goal of philosophical inquiry. At this time of his life, Diderot resisted Maupertuis's theory of the unity of vital force in the universe, or perhaps we should rather say that he saw how open it was to criticism. His resistance has none of his usual air of vehement conviction. However that may be, the theory excited his interest, and fitted in with the train of meditation which his thoughts about the Encyclopaedia had already set in motion, and of which the _Pensees Philosophiques_ of 1746 were the cruder prelude.

[207] As to the precise drift of Maupertuis's theme, see Lange, _Gesch. d. Materialismus_, i. 413, _n._ 37. Also Rosenkranz, i. 134.

[208] In 1765 Grimm describes the principle of Leibnitz and Maupertuis as "gaining on us on every side."--_Corr. Lit._, iv. 186.

The _Thoughts on the Interpretation of Nature_ are, in form as in t.i.tle, imitated from those famous _Aphorismi de Interpretatione Naturae et Regni Hominis_, which are more shortly known to all men as Bacon's _Novum Organum_.[209] The connection between the aphorisms is very loosely held. Diderot began by premising that he would let his thoughts follow one another under his pen, in the order in which the subjects came up in his mind; and he kept his word. Their general scope, so far as it is capable of condensed expression, may be described as a reconciliation between the two great cla.s.ses into which Diderot found thinkers upon Nature to be divided; those who have many instruments and few ideas, and those who have few instruments and many ideas,--in other words, between men of science without philosophy, and philosophers without knowledge of experimental science.

[209] Palissot, in the _Philosophers_, concocted some very strained satire on the too pompous opening of the _Interpretation of Nature_.

Act I. sc. 2.

In the region of science itself, again, Diderot foresees as great a change as in the relations between science and philosophy. "We touch the moment of a great revolution in the sciences. From the strong inclination of men's minds towards morals, literature, the history of nature and experimental physics, I would almost venture to a.s.sert that before the next hundred years are over, there will not be three great geometers to be counted in Europe. This science will stop short where the Bernouillis, the Eulers, the Maupertuis, the Clairauts, the Fontaines, the D'Alemberts, the Lagranges have left it. They will have fixed the Pillars of Hercules. People will go no further." Those who have read Comte's angry denunciations of the perversions of geometry by means of algebra, and of the waste of intellectual force in modern a.n.a.lysis,[210] will at least understand how such a view as Diderot's was possible. And no one will be likely to deny that, whether or not the pillars of the geometrical Hercules were finally set a hundred years ago, the great discoveries of the hundred years since Diderot have been, as he predicted, in the higher sciences. The great misfortune of France was that the supremacy of geometry coincided with the opening of the great era of political discussion. The definitions of Montesquieu's famous book, which opened the political movement in literature, have been shown to be less those of a jurisconsult than of a geometer.[211]

Social truths, with all their profound complexity, were handled like propositions in Euclid, and logical deductions from arbitrary premises were treated as accurate representations of real circ.u.mstance. The repulse of geometry to its proper rank came too late.

[210] Comte's _System of Positive Polity_, i. 380, etc. English translation, 1875.

[211] By F. Sclopis, quoted in M. Vian's _Hist. de Montesquieu_, p.

51.

Comte always liberally recognised Diderot's genius, and any reader of Comte's views on the necessities of subjective synthesis will discern the germ of that doctrine in the following remarkable section:

"When we compare the infinite mult.i.tude of the phenomena of nature with the limits of our understandings and the weakness of our organs, can we ever expect anything else from the slowness of our work, from the long and frequent interruptions, and from the rarity of creative genius than a few broken and separated pieces of the great chain that binds all things together? Experimental philosophy might work for centuries of centuries, and the materials that it had heaped up, finally reaching in their number beyond all combination, would still be far removed from an exact enumeration.

How many volumes would it not need to contain the mere terms by which we should designate the distinct collections of phenomena, if the phenomena were known? When will the philosophic language be complete? If it were complete, who among men would be able to know it? If the Eternal, to manifest his power still more plainly than by the marvels of nature, had deigned to develop the universal mechanism on pages traced by his own hand, do you suppose that this great book would be more comprehensible to us than the universe itself? How many pages of it all would have been intelligible to the philosopher who, with all the force of head that had been conferred upon him, was not sure of having grasped all the conclusions by which an old geometer determined the relation of the sphere to the cylinder? We should have in such pages a fairly good measure of the reach of men's minds, and a still more pungent satire on our vanity. We should say, Fermat went to such a page, Archimedes went a few pages further.

"What then is our end? The execution of a work that can never be achieved, and which would be far beyond human intelligence if it were achieved. Are we not more insensate than the first inhabitants of the plain of Shinar? We know the immeasurable distance between the earth and the heavens, and still we insist on rearing our tower.

"But can we presume that there will not come a time when our pride will abandon the work in discouragement? What appearance is there that, narrowly lodged and ill at its ease here below, our pride should obstinately persist in constructing an uninhabitable palace beyond the earth's atmosphere? Even if it should so insist, would it not be arrested by the confusion of tongues, which is already only too perceptible and too inconvenient in natural history?

Besides, it is utility that circ.u.mscribes all. It will be utility that in a few centuries will set bounds to experimental physics, as it is on the eve of setting bounds to geometry. I grant centuries to this study, because the sphere of its utility is infinitely more extensive than that of any abstract science, and it is without contradiction the base of our real knowledge."[212]

[212] _Oeuv._, ii. 12, 13, -- 6. See the same idea in the Encyclopaedia, above, vol. i. pp. 225-227.

We cannot wonder that when Comte drew up his list of the hundred and fifty volumes that should form the good Positivist's library in the nineteenth century, he should have placed Diderot's _Interpretation of Nature_ on one side of Descartes' _Discourse on Method_, with Bacon's _Novum Organum_ on the other.

The same spirit finds even stronger and more distinct expression in a later aphorism:--"Since the reason cannot understand everything, imagination foresee everything, sense observe everything, nor memory retain everything; since great men are born at such remote intervals, and the progress of science is so interrupted by revolution, that whole ages of study are pa.s.sed in recovering the knowledge of the centuries that are gone,--to observe everything in nature without distinction is to fail in duty to the human race. Men who are beyond the common run in their talents ought to respect themselves and posterity in the employment of their time. What would posterity think of us if we had nothing to transmit to it save a complete insectology, an immense history of microscopic animals? No--to the great geniuses great objects, little objects to the little geniuses" (-- 54).

Diderot, while thus warning inquirers against danger on one side, was alive to the advantages of stubborn and unlimited experiment on the other. "When you have formed in your mind," he says, "one of those systems which require to be verified by experience, you ought neither to cling to it obstinately nor abandon it lightly. People sometimes think their conjectures false, when they have not taken the proper measures to find them true. Obstinacy, even, has fewer drawbacks than the opposite excess. By multiplying experiments, if you do not find what you want, it may happen that you will come on something better. _Never is time employed in interrogating nature entirely lost_" (-- 42). The reader will not fail to observe that this maxim is limited by the condition of verifiableness. Of any system that could not be verified by experience Diderot would have disdained to speak in connection with the interpretation of nature.

This, of course, did not prevent him from hypothesis and prophecy which he himself had not the means of justifying. For example, he said that just as in mathematics, by examining all properties of a curve we find that they are one and the same property presented under different faces, so in nature when experimental physics are more advanced, people will recognise that all the phenomena, whether of weight, or elasticity, or magnetism, or electricity, are only different sides of the same affection (-- 44). But he was content to leave it to posterity, and to build no fabric on unproved propositions.

In the same scientific spirit he penetrated the hollowness of every system dealing with Final Causes:

"The physicist, whose profession is to instruct and not to edify, will abandon the _Why_, and will busy himself only with the _How_.... How many absurd ideas, false suppositions, chimerical notions in those hymns which some rash defenders of final causes have dared to compose in honour of the Creator? Instead of sharing the transports of admiration of the prophet, and crying out at the sight of the unnumbered stars that light up the midnight sky, _The heavens declare the glory of G.o.d, and the firmament sheweth his handiwork_, they have given themselves up to the superst.i.tion of their conjectures. Instead of adoring the All-Powerful in the creation of nature, they have prostrated themselves before the phantoms of their imagination. If any one doubts the justice of my reproach, I invite him to compare Galen's treatise on the use of parts of the human body, with the physiology of Boerhaave, and the physiology of Boerhaave with that of Haller; I invite posterity to compare the systematic or pa.s.sing views of Haller with what will be the physiology of future times. Man praises the Eternal for his own poor views; and the Eternal who hears from the elevation of his throne, and who knows his own design, accepts the silly praise and smiles at man's vanity" (-- 56).

The world has advanced rapidly along this path since Diderot's day, and has opened out many new and unsuspected meanings by the way. Perhaps the advance has been less satisfactory in working out, in a scientific way, the philosophy that is implied in the following adaptation of the Leibnitzian and Maupertuisian suggestion of the law of economy in natural forces:--"Astonishment often comes from our supposing several marvels, where in truth there is only one; from our imagining in nature as many particular acts as we can count phenomena, whilst _nature has perhaps in reality never produced more than one single act_. It seem even that, if nature had been under the necessity of producing several acts, the different results of such acts would be isolated; that there would be collections of phenomena independent of one another, and that the general chain of which philosophy a.s.sumes the continuity, would break in many places. _The absolute independence of a single fact is incompatible with the idea of an All; and without the idea of a Whole, there can be no Philosophy_" (-- 11).

At length Diderot concludes by a series of questions which he thinks that philosophers may perhaps count worthy of discussion. What is the difference, for example, between living matter and dead? Does the energy of a living molecule vary by itself, or according to the quant.i.ty, the quality, the forms of the dead or living matter with which it is united?

We need not continue the enumeration, because Diderot himself suddenly brings them to an end with a truly admirable expression of his sense of how unworthy they are of the attention of serious men, who are able to measure the difference between a wise and beneficent use of intelligence, and a foolish and wasteful misuse of it. "When I turn my eyes," he says, "to the works of men, and see the cities that are built on every side, all the elements yoked to our service, languages fixed, nations civilised, harbours constructed, lands and skies measured--then the world seems to me very old. When I find man uncertain as to the first principles of medicine and agriculture, as to the properties of the commonest substances, as to knowledge of the maladies that afflict him, as to the pruning of trees, as to the best form for the plough, then it seems as if the earth had only been inhabited yesterday. And if men were wise, they would at last give themselves up to such inquiries as bear on their wellbeing, and would not take the trouble to answer my futile questions for a thousand years at the very soonest; or perhaps, even, considering the very scanty extent that they occupy in s.p.a.ce and time, they would never deign to answer them at all."

II.

In 1769 Diderot composed three dialogues, of which he said that, with a certain mathematical memoir, they were the only writings of his own with which he was contented. The first is a dialogue between himself and D'Alembert; the second is D'Alembert's Dream, in which D'Alembert in his sleep continues the discussion, while Mdlle. Lespina.s.se, who is watching by his bedside, takes down the dreamer's words; in the third, Mdlle.

Lespina.s.se and the famous physician, Bordeu, conclude the matter.[213]

It is impossible, Diderot said to Mdlle. Voland, to be more profound and more mad: it is at once a supreme extravagance, and the most deep-reaching philosophy. He congratulated himself on the cleverness of placing his ideas in the mouth of a man who dreams, on the ground that we must often give to wisdom the air of madness, in order to secure admittance. Mdlle. Lespina.s.se was not so complacent. She made D'Alembert insist that the dialogue should be destroyed, and Diderot believed that he had burned the only existing copy. As a matter of fact, the ma.n.u.script was not published until 1830, when all the people concerned had long been reduced to dust. There are five or six pages, Diderot said to Mdlle. Voland, which would make your sister's hair stand on end. A man may be much less squeamish than Mdlle. Voland's sister, and still p.r.o.nounce the imaginative invention of D'Alembert's Dream, and the sequel, to be as odious as anything since the freaks of filthy Diogenes in his tub. Two remarks may be made on this strange production. First, Diderot never intended the dialogues for the public eye. He would have been as shocked as the Archbishop of Paris himself, if he had supposed that they would become accessible to everybody who knows how to read.

Second, though they are in form the most ugly and disgusting piece in the literature of philosophy, they testify in their own way to Diderot's sincerity of interest in his subject. Science is essentially unsparing and unblushing, and D'Alembert's Dream plunged exactly into those parts of physiology which are least fit to be handled in literature. The attempt to give an air of polite comedy to functions and secretions must be p.r.o.nounced detestable, in spite of the dialectical acuteness and force with which Diderot pressed his point.

[213] _Oeuv._, ii.

It would be impossible, in a book not exclusively designed for a public of professors, to give a full account of these three dialogues. It is indispensable to describe their drift, because it is here that Diderot figures definitely as a materialist. Diderot was in no sense the originator of the French materialism of the eighteenth century. He was preceded by Maupertuis, by Robinet, and by La Mettrie; and we have already seen that when he composed the Thoughts on the Interpretation of Nature (1754), he did not fully accept Maupertuis's materialistic thesis. Lange has shown that at a very early period in the movement the most consistent materialism was ready and developed, while such leaders of the movement as Voltaire and Diderot still leaned either on deism, or on a mixture of deism and scepticism.[214] The philosophy of D'Alembert's Dream is definite enough, and far enough removed alike from deism and scepticism.

[214] _Gesch. d. Materialismus_, i. 309, 310, etc.

"The thinking man is like a musical instrument. Suppose a clavecin to have sensibility and memory, and then say whether it would not repeat of itself the airs that you have played on its keys. We are instruments endowed with sensibility and memory. Our senses are so many keys, pressed by the nature that surrounds them, and they often press one another; and this, according to my judgment, is all that pa.s.ses in a clavecin organised as you and I are organised.

"There is only one substance in the world. The marble of the statue makes the flesh of the man, and conversely. Reduce a block of marble to impalpable powder; mix this powder with humus, or vegetable earth; knead them well together; water the mixture; let it rot for a year, two years--time does not count. In this you sow the plant, the plant nourishes the man, and hence the pa.s.sage from marble to tissue.

"Do you see this egg? With that you overturn all the schools of theology and all the temples of the earth. It is an insensible ma.s.s before the germ is introduced into it; and, after the germ is introduced, there is still an insensible ma.s.s, for the germ itself is only an inert fluid.

How does this ma.s.s pa.s.s to another organisation, to life, to sensibility? By heat. What will produce heat? Movement. What will be the successive effects of movement? First, an oscillating point, a thread that extends, the flesh, the beak, and so forth."

Then follows the application of the same ideas to the reproduction of man--a region whither it is not convenient to follow the physiological inquirer. The result as to the formation of the organic substance in man is as unflinching as the materialism of Buchner.

But doctor, cries Mdlle. Lespina.s.se, what becomes of vice and virtue? Virtue, that word so holy in all languages, that idea so sacred among all nations?

BORDEU. We must transform it into beneficence, and its opposite into the idea of maleficence. A man is happily or unhappily born; people are irresistibly drawn on by the general torrent that conducts one to glory, the other to ignominy.

MDLLE. LESPINa.s.sE. And self-esteem, and shame, and remorse?

BORDEU. Proclivities, founded on the ignorance or the vanity of a being who imputes to himself the merit or the demerit of a necessary instant.

MDLLE. LESPINa.s.sE. And rewards and punishments?

BORDEU. Means of correcting the modifiable being that we call bad, and encouraging the other that we call good.[215]

[215] _Oeuv._, ii. 176.

The third dialogue we must leave. The fact that German books are written for a public of specialists allows Dr. Rosenkranz to criticise these dialogues with a freedom equal to Diderot's own, and his criticism is as full as usual of candour, patience, and weight. An English writer must be content to pa.s.s on, and his contentment may well be considerable, for the subject is perhaps that on which, above all others, it is most difficult to say any wise word.

III.

The Plan of a University for the Government of Russia was the work of Diderot's last years, but no copy of it was given to the public before 1813-14, when M. Guizot published extracts from an autograph ma.n.u.script confided to him by Suard. Diderot, with a characteristic respect for competence, with which no egotism can ever interfere in minds of such strength and veracity as his, began by urging the Empress to consult Ernesti of Leipsic, the famous editor of Cicero, and no less famous in his day (1707-1781) for the changes that he introduced into the system of teaching in the German universities. Of Oxford and Cambridge Diderot spoke more kindly than they then deserved.

The one strongly marked idea of the plan is what might have been expected from the editor of the Encyclopaedia, namely, the elevation of what the Germans call real or technological instruction, and the banishment of pure literature as a subject of study from the first to the last place in the course. In the faculty of arts the earliest course begins with arithmetic, algebra, the calculation of probabilities, and geometry. Next follow physics and mechanics. Then astronomy. Fourthly, natural history and experimental physics. In the fifth cla.s.s, chemistry and anatomy. In the sixth, logic and grammar. In the seventh, the language of the country. And it was not until the eighth, that Greek and Latin, eloquence and poetry, took their place among the objects or instruments of education. Parallel with this course, the student was to follow the first principles of metaphysics, of universal morality, and of natural and revealed religion. Here, too, history and geography had a place. In a third parallel, perspective and drawing accompanied the science of the first, and the philosophy and history of the second.

In the th.o.r.n.y field of religious instruction, Diderot expresses no opinion of his own, beyond saying that it is natural for the Empress's subjects to conform to her way of thinking. As her majesty thinks that the fear of pains to come has much influence on men's actions, and is persuaded that the total of small daily advantages produced by belief outweighs the total of evils wrought by sectarianism and intolerance, therefore students ought to be instructed in the mystery of the distinction of the two substances, in the immortality of the soul, and so forth.[216]

[216] _Oeuv._, iii. 490.

There is a story that one evening at St. Petersburg, Diderot was declaiming with stormy eloquence against the baseness of those who flatter kings; for such, he said, there ought to be a deeper and a fiercer h.e.l.l. "Tell me, Diderot," said the Empress by and by, "what they say in Paris about the death of my husband." Instead of telling her the plain truth that everybody said that Peter had been murdered by her orders, the philosopher poured out a stream of the smoothest things.

"Come now," said Catherine suddenly, "confess, if you are not walking along the path that leads to your deep h.e.l.l, you are certainly coming very close to purgatory." Diderot's elaborate concessions to her majesty's political religion would, it is to be feared, have brought him still further in the same sulphureous track.