Chapter II: Forensic Speeches (13)

Besides the last two parts of the _Principles of Philosophy_, the physical writings of Descartes include the _Dioptrics_ and _Meteors_, as well as passages in the letters. His optical investigations are perhaps the subject in which he most contributed to the progress of science; and the lucidity of exposition which marks his _Dioptrics_ stands conspicuous even amid the generally luminous style of his works. Its object is a practical one, to determine by scientific considerations the shape of lens best adapted to improve the capabilities of the telescope, which had been invented not long before. The conclusions at which he arrives have not been so useful as he imagined, in consequence of the mechanical difficulties. But the investigation by which he reaches them has the merit of first prominently publishing and establishing the law of the refraction of light. Attempts have been made, principally founded on some remarks of Huygens, to show that Descartes had learned the principles of refraction from the manuscript of a treatise by Willebrord Snell, but the facts are uncertain; and, so far as Descartes founds his optics on any one, it is probably on the researches of Kepler. In any case the discovery is to some extent his own, for his proof of the law is founded upon the theory that light is the propagation of the aether in straight lines from the sun or luminous body to the eye (see LIGHT). Thus he approximates to the wave theory of light, though he supposed that the transmission of light was instantaneous. The chief of his other contributions to optics was the explanation of the rainbow--an explanation far from complete, since the unequal refrangibility of the rays of light was yet undiscovered--but a decided advance upon his predecessors, notably on the _De radiis visus et lucis_ (1611) of Marc-Antonio de Dominis, archbishop of Spalato.

If Descartes had contented himself with thus explaining the phenomena of gravity, heat, magnetism, light and similar forces by means of the molecular movements of his vortices, even such a theory would have excited admiration. But he did not stop short in the region of what is usually termed physics. Chemistry and biology are alike swallowed up in the one science of physics, and reduced to a problem of mechanism. This theory, he believed, would afford an explanation of every phenomenon whatever, and in nearly every department of knowledge he has given specimens of its power. But the most remarkable and daring application of the theory was to account for the phenomena of organic life, especially in animals and man. "If we possessed a thorough knowledge," he says,[38] "of all the parts of the seed of any species of animal (e.g. man), we could from that alone, by reasons entirely mathematical and certain, deduce the whole figure and conformation of each of its members, and, conversely, if we knew several peculiarities of this conformation, we could from these deduce the nature of its seed." The organism in this way is regarded as a machine, constructed from the particles of the seed, which in virtue of the laws of motion have arranged themselves (always under the governing power of God) in the particular animal shape in which we see them. The doctrine of the circulation of the blood, which Descartes adopted from Harvey, supplied additional arguments in favour of his mechanical theory, and he probably did much to popularize the discovery. A fire without light, compared to the heat which gathers in a haystack when the hay has been stored before it was properly dry--heat, in short, as an agitation of the particles--is the motive cause of the contraction and dilatations of the heart. Those finer particles of the blood which become extremely rarefied during this process pass off in two directions--one portion, and the least important in the theory, to the organs of generation, the other portion to the cavities of the brain. There not merely do they serve to nourish the organ, they also give rise to a fine ethereal flame or wind through the action of the brain upon them, and thus form the so-called "animal" spirits. From the brain these spirits are conveyed through the body by means of the nerves, regarded by Descartes as tubular vessels, resembling the pipes conveying the water of a spring to act upon the mechanical appliances in an artificial fountain. The nerves conduct the animal spirits to act upon the muscles, and in their turn convey the impressions of the organs to the brain.

Automatism.

Man and the animals as thus described are compared to automata, and termed machines. The vegetative and sensitive souls which the Aristotelians had introduced to break the leap between inanimate matter and man are ruthlessly swept away; only one soul, the rational, remains, and that is restricted to man. One hypothesis supplants the various principles of life; the rule of absolute mechanism is as complete in the animal as in the cosmos. Reason and thought, the essential quality of the soul, do not belong to the brutes; there is an impassable gulf fixed between man and the lower animals. The only sure sign of reason is the power of language--i.e. of giving expression to general ideas; and language in that sense is not found save in man. The cries of animals are but the working of the curiously-contrived machine, in which, when one portion is touched in a certain way, the wheels and springs concealed in the interior perform their work, and, it may be, a note supposed to express joy or pain is evolved; but there is no consciousness or feeling. "The animals act naturally and by springs, like a watch."[39] "The greatest of all the prejudices we have retained from our infancy is that of believing that the beasts think."[40] If the beasts can properly be said to see at all, "they see as we do when our mind is distracted and keenly applied elsewhere; the images of outward objects paint themselves on the retina, and possibly even the impressions made in the optic nerves determine our limbs to different movements, but we feel nothing of it all, and move as if we were automata."[41] The sentience of the animal to the lash of his tyrant is not other than the sensitivity of the plant to the influences of light and heat. It is not much comfort to learn further from Descartes that "he denies life to no animal, but makes it consist in the mere heat of the heart. Nor does he deny them feeling in so far as it depends on the bodily organs."[42]

Descartes, with an unusual fondness for the letter of Scripture, quotes oftener than once in support of this monstrous doctrine. the dictum, "the blood is the life"; and he remarks, with some sarcasm possibly, that it is a comfortable theory for the eaters of animal flesh. And the doctrine found acceptance among some whom it enabled to get rid of the difficulties raised by Montaigne and those who allowed more difference between animal and animal than between the higher animals and man. It also encouraged vivisection--a practice common with Descartes himself.[43] The recluses of Port Royal seized it eagerly, discussed automatism, dissected living animals in order to show to a morbid curiosity the circulation of the blood, were careless of the cries of tortured dogs, and finally embalmed the doctrine in a syllogism of their logic,--No matter thinks; every soul of beast is matter: therefore no soul of beast thinks.

Relation of mind and body.

But whilst all the organic processes in man go on mechanically, and though by reflex action he may repel attack unconsciously, still the first affirmation of the system was that man was essentially a thinking being; and, while we retain this original dictum, it must not be supposed that the mind is a mere spectator, or like the boatman in the boat. Of course a unity of nature is impossible between mind and body so described. And yet there is a unity of composition, a unity so close that the compound is "really one and in a sense indivisible." You cannot in the actual man cut soul and body asunder; they interpenetrate in every member. But there is one point in the human frame--a point midway in the brain, single and free, which may in a special sense be called the seat of the mind. This is the so-called conarion, or pineal gland, where in a minimized point the mind on one hand and the vital spirits on the other meet and communicate. In that gland the mystery of creation is concentrated; thought meets extension and directs it; extension moves towards thought and is perceived. Two clear and distinct ideas, it seems, produce an absolute mystery. Mind, driven from the field of extension, erects its last fortress in the pineal gland. In such a state of despair and destitution there is no hope for spiritualism, save in God; and Clauberg, Geulincx and Malebranche all take refuge under the shadow of his wings to escape the tyranny of extended matter.

Psychology.

In the psychology of Descartes there are two fundamental modes of thought,--perception and volition. "It seems to me," he says, "that in receiving such and such an idea the mind is passive, and that it is active only in volition; that its ideas are put in it partly by the objects which touch the senses, partly by the impressions in the brain, and partly also by the dispositions which have preceded in the mind itself and by the movements of its will."[44] The will, therefore, as being more originative, has more to do with true or false judgments than the understanding. Unfortunately, Descartes is too lordly a philosopher to explain distinctly what either understanding or will may mean. But we gather that in two directions our reason is bound up with bodily conditions, which make or mar it, according as the will, or central energy of thought, is true to itself or not. In the range of perception, intellect is subjected to the material conditions of sense, memory and imagination; and in infancy, when the will has allowed itself to assent precipitately to the conjunctions presented to it by these material processes, thought has become filled with obscure ideas. In the moral sphere the passions or emotions (which Descartes reduces to the six primitive forms of admiration, love, hatred, desire, joy and sadness) are the perceptions or sentiments of the mind, caused and maintained by some movement of the vital spirits, but specially referring to the mind only. The presentation of some object of dread, for example, to the eye has or may have a double effect. On one hand the animal spirits "reflected"[45] from the image formed on the pineal gland proceed through the nervous tubes to make the muscles turn the back and lift the feet, so as to escape the cause of the terror. Such is the reflex and mechanical movement independent of the mind. But, on the other hand, the vital spirits cause a movement in the gland by which the mind perceives the affection of the organs, learns that something is to be loved or hated, admired or shunned. Such perceptions dispose the mind to pursue what nature dictates as useful. But the estimate of goods and evils which they give is indistinct and unsatisfactory. The office of reason is to give a true and distinct appreciation of the values of goods and evils; or firm and determinate judgments touching the knowledge of good and evil are our proper arms against the influence of the passions.[46] We are free, therefore, through knowledge: _ex magna luce in intellectu sequitur magna propensio in voluntate_, and _omnis peccans est ignorans_. "If we clearly see that what we are doing is wrong, it would be impossible for us to sin, so long as we saw it in that light."[47] Thus the highest liberty, as distinguished from mere indifference, proceeds from clear and distinct knowledge, and such knowledge can only be attained by firmness and resolution, i.e. by the continued exercise of the will. Thus in the perfection of man, as in the nature of God, will and intellect must be united. For thought, will is as necessary as understanding. And innate ideas therefore are mere capacities or tendencies,--possibilities which apart from the will to think may be regarded as nothing at all.

_The Cartesian School._--The philosophy of Descartes fought its first battles and gained its first triumphs in the country of his adoption. In his lifetime his views had been taught in Utrecht and Leiden. In the universities of the Netherlands and of lower Germany, as yet free from the conservatism of the old-established seats of learning, the new system gained an easy victory over Aristotelianism, and, as it was adapted for lectures and examinations, soon became almost as scholastic as the doctrines it had supplanted. At Leiden, Utrecht, Groningen, Franeker, Breda, Nimeguen, Harderwyk, Duisburg and Herborn, and at the Catholic university of Louvain, Cartesianism was warmly expounded and defended in seats of learning, of which many are now left desolate, and by adherents whose writings have for the most part long lost interest for any but the antiquary.

Holland.

The Cartesianism of Holland was a child of the universities, and its literature is mainly composed of commentaries upon the original texts, of theses discussed in the schools, and of systematic expositions of Cartesian philosophy for the benefit of the student. Three names stand out in this Cartesian professoriate,--Wittich, Clauberg and Geulincx. Christoph Wittich (1625-1687), professor at Duisburg and Leiden, is a representative of the moderate followers who professed to reconcile the doctrines of their school with the faith of Christendom and to refute the theology of Spinoza. Johann Clauberg (q.v.) commented clause by clause upon the _Meditations_ of Descartes; but he specially claims notice for his work _De corporis et animae in homine conjunctione_, where he maintains that the bodily movements are merely procatarctic causes (i.e. antecedents, but not strictly causes) of the mental action, and sacrifices the independence of man to the omnipotence of God. The same tendency is still more pronounced in Arnold Geulincx (q.v.). With him the reciprocal action of mind and body is altogether denied; they resemble two clocks, so made by the artificer as to strike the same hour together. The mind can act only upon itself; beyond that limit, the power of God must intervene to make any seeming interaction possible between body and soul. Such are the half-hearted attempts at consistency in Cartesian thought, which eventually culminate in the pantheism of Spinoza (see CARTESIANISM).

Descartes occasionally had not scrupled to interpret the Scriptures according to his own tenets, while still maintaining, when their letter contradicted him, that the Bible was not meant to teach the sciences. Similar tendencies are found amongst his followers. Whilst Protestant opponents put him in the list of atheists like Vanini, and the Catholics held him as dangerous as Luther or Calvin, there were zealous adherents who ventured to prove the theory of vortices in harmony with the book of Genesis. It was this rationalistic treatment of the sacred writings which helped to confound the Cartesians with the allegorical school of John Cocceius, as their liberal doctrines in theology justified the vulgar identification of them with the heresies of Socinian and Arminian. The chief names in this advanced theology connected with Cartesian doctrines are Ludwig Meyer, the friend and editor of Spinoza, author of a work termed _Philosophia scripturae interpres_ (1666); Balthasar Bekker, whose _World Bewitched_ helped to discredit the superstitious fancies about the devil; and Spinoza, whose _Tractatus theologico-politicus_ is in some respects the classical type of rational criticism up to the present day. Against this work and the _Ethics_ of Spinoza the orthodox Cartesians (who were in the majority), no less than sceptical hangers-on like Bayle, raised an all but universal howl of reprobation, scarcely broken for about a century.

France.

In France Cartesianism won society and literature before it penetrated into the universities. Clerselier (the friend of Descartes and his literary executor), his son-in-law Rohault (who achieved that relationship through his Cartesianism), and others, opened their houses for readings to which the intellectual world of Paris--its learned professors not more than the courtiers and the fair sex,--flocked to hear the new doctrines explained, and possibly discuss their value. Grand seigneurs, like the prince of Condé, the duc de Nevers and the marquis de Vardes, were glad to vary the monotony of their feudal castles by listening to the eloquent rehearsals of Malebranche or Regis. And the salons of Mme de Sévigné, of her daughter Mme de Grignan, and of the duchesse de Maine for a while gave the questions of philosophy a place among the topics of polite society, and furnished to Molière the occasion of his _Femmes savantes_. The Château of the duc de Luynes, the translator of the _Meditations_, was the home of a Cartesian club, that discussed the questions of automatism and of the composition of the sun from filings and parings, and rivalled Port Royal in its vivisections. The cardinal de Retz in his leisurely age at Commercy found amusement in presiding at disputations between the more moderate Cartesians and Don Robert Desgabets, who interpreted Descartes in an original way of his own. Though rejected by the Jesuits, who found peripatetic formulae a faithful weapon against the enemies of the church, Cartesianism was warmly adopted by the Oratory, which saw in Descartes something of St Augustine, by Port Royal, which discovered a connexion between the new system and Jansenism, and by some amongst the Benedictines and the order of Ste Geneviève.

The popularity which Cartesianism thus gained in the social and literary circles of the capital was largely increased by the labours of Pierre-Sylvain Regis (1632-1707). On his visit to Toulouse in 1665, with a mission from the Cartesian chiefs, his lectures excited boundless interest; ladies threw themselves with zeal and ability into the study of philosophy; and Regis himself was made the guest of the civic corporation. In 1671 scarcely less enthusiasm was roused in Montpellier; and in 1680 he opened a course of lectures at Paris, with such acceptance that hearers had to take their seats in advance. Regis, by removing the paradoxes and adjusting the metaphysics to the popular powers of apprehension, made Cartesianism popular, and reduced it to a regular system.

But a check was at hand. Descartes, in his correspondence with the Jesuits, had shown an almost cringing eagerness to have their powerful organization on his side. Especially he had written to Père Mesland, one of the order, to show how the Catholic doctrine of the eucharist might be made compatible with his theories of matter. But his undue haste to arrange matters with the church only served to compromise him more deeply. Unwise admirers and malicious opponents exaggerated the theological bearings of his system in this detail; and the efforts of the Jesuits succeeded in getting the works of Descartes, in November 1663, placed upon the index of prohibited books,--_donec corrigantur_. Thereupon the power of church and state enforced by positive enactments the passive resistance of old institutions to the novel theories. In 1667, the oration at the interment was forbidden by royal order. In 1669, when the chair of philosophy at the Collège Royal fell vacant, one of the four selected candidates had to sustain a thesis against "the pretended new philosophy of Descartes." In 1671 the archbishop of Paris, by the king's order, summoned the heads of the university to his presence, and enjoined them to take stricter measures against philosophical novelties dangerous to the faith. In 1673 a decree of the parlement against Cartesian and other unlicensed theories was on the point of being issued, and was only checked in time by the appearance of a burlesque mandamus against the intruder Reason, composed by Boileau and some of his brother-poets. Yet in 1675 the university of Angers was empowered to repress all Cartesian teaching within its domain, and actually appointed a commission charged to look for such heresies in the theses and the students' note-books of the college of Anjou belonging to the Oratory. In 1677 the university of Caen adopted not less stringent measures against Cartesianism. And so great was the influence of the Jesuits, that the congregation of St Maur, the canons of Ste Geneviève, and the Oratory laid their official ban on the obnoxious doctrines. From the real or fancied _rapprochements_ between Cartesianism and Jansenism, it became for a while impolitic, if not dangerous, to avow too loudly a preference for Cartesian theories. Regis was constrained to hold back for ten years his _System of Philosophy_; and when it did appear, in 1690, the name of Descartes was absent from the title-page. There were other obstacles besides the mild persecutions of the church. Pascal and other members of Port Royal openly expressed their doubts about the place allowed to God in the system; the adherents of Gassendi met it by resuscitating atoms; and the Aristotelians maintained their substantial forms as of old; the Jesuits argued against the arguments for the being of God, and against the theory of innate ideas; whilst Pierre Daniel Huet (1630-1721), bishop of Avranches, once a Cartesian himself, made a vigorous onslaught on the contempt in which his former comrades held literature and history, and enlarged on the vanity of all human aspirations after rational truth.

The greatest and most original of the French Cartesians was Malebranche (q.v.). His _Recherche de la vérité_, in 1674, was the baptism of the system into a theistic religion which borrowed its imagery from Augustine; it brought into prominence the metaphysical base which Louis Delaforge, Jacques Rohault and Regis had neither cared for nor understood. But this doctrine was a criticism and a divergence, no less than a consequence, from the principles in Descartes; and it brought upon Malebranche the opposition, not merely of the Cartesian physicists, but also of Arnauld, Fénelon and Bossuet, who found, or hoped to find, in the _Meditations_, as properly understood, an ally for theology. Popular enthusiasm, however, was with Malebranche, as twenty years before it had been with Descartes; he was the fashion of the day; and his disciples rapidly increased both in France and abroad.

In 1705 Cartesianism was still subject to prohibitions from the authorities; but in a project of new statutes, drawn up for the faculty of arts at Paris in 1720, the _Method_ and _Meditations_ of Descartes were placed beside the _Organon_ and the _Metaphysics_ of Aristotle as text-books for philosophical study. And before 1725, readings, both public and private, were given from Cartesian texts in some of the Parisian colleges. But when this happened, Cartesianism was no longer either interesting or dangerous; its theories, taught as ascertained and verified truths, were as worthless as the systematic verbiage which preceded them. Already antiquated, it could not resist the wit and raillery with which Voltaire, in his _Lettres sur les Anglais_ (1728), brought against it the principles and results of Locke and Newton. The old Cartesians, Jean Jacques Dortous de Mairan (1678-1771) and especially Fontenelle, with his _Théorie des tourbillons_ (1752), struggled in vain to refute Newton by styling attraction an occult quality. Fortunately the Cartesian method had already done its service, even where the theories were rejected. The Port Royalists, Pierre Nicole (1625-1695) and Antoine Arnauld (1612-1694), had applied it to grammar and logic; Jean Domat or Daumat (1625-1696) and Henri François Daugesseau (1668-1751) to jurisprudence; Fontenelle, Charles Perrault (1628-1703) and Jean Terrasson (1670-1750) to literary criticism, and a worthier estimate of modern literature. Though it never ceased to influence individual thinkers, it had handed on to Condillac its popularity with the masses. A Latin abridgment of philosophy, dated 1784, tells us that the innate ideas of Descartes are founded on no arguments, and are now universally abandoned. The ghost of innate ideas seems to be all that it had left.

Germany.

In Germany a few Cartesian lecturers taught at Leipzig and Halle, but the system took no root, any more than in Switzerland, where it had a brief reign at Geneva after 1669. In Italy the effects were more permanent. What is termed the iatro-mechanical school of medicine, with G. A. Borelli (1608-1679) as its most notable name, entered in a way on the mechanical study of anatomy suggested by Descartes, but was probably much more dependent upon the positive researches of Galileo. At Naples there grew up a Cartesian school, of which the best known members are Michel Angelo Fardella (1650-1708) and Cardinal Gerdil (1718-1802), both of whom, however, attached themselves to the characteristic views of Malebranche.

England.

In England Cartesianism took but slight hold. Henry More, who had given it a modified sympathy in the lifetime of the author, became its opponent in later years; and Cudworth differed from it in most essential points. Antony Legrand, from Douai, attempted to introduce it into Oxford, but failed. He is the author of several works, amongst others a system of Cartesian philosophy, where a chapter on "Angels" revives the methods of the schoolmen. His chief opponent was Samuel Parker (1640-1688), bishop of Oxford, who, in his attack on the irreligious novelties of the Cartesian, treats Descartes as a fellow-criminal in infidelity with Hobbes and Gassendi. Rohault's version of the Cartesian physics was translated into English; and Malebranche found an ardent follower in John Norris (1667-1711). Of Cartesianism towards the close of the 17th century the only remnants were an overgrown theory of vortices, which received its death-blow from Newton, and a dubious phraseology anent innate ideas, which found a witty executioner in Locke.

For an account of the metaphysical doctrines of Descartes, in their connexions with Malebranche and Spinoza, see CARTESIANISM.

BIBLIOGRAPHY.--I. _Editions and Translations._--The collected works
of Descartes were published in Latin in 8 vols. at Amsterdam
(1670-1683), in 7 vols. at Frankfort (1697) and in 9 vols. by Elzevir
(1713); in French in 13 vols. (Paris, 1724-1729), republished by
Victor Cousin (Paris, 1824-1826) in 11 vols., and again under the
authority of the minister of public instruction by C. Adam and P.
Tannery (1897 foll.). These include his so-called posthumous works.
_The Rules for the Direction of the Mind_, _The Search for Truth by
the Light of Nature_, and other unimportant fragments, published (in
Latin) in 1701. In 1859-1860 Foucher de Careil published in two parts
some unedited writings of Descartes from copies taken by Leibnitz
from the original papers. Six editions of the _Opera philosophica_
appeared at Amsterdam between 1650 and 1678; a two-volume edition at
Leipzig in 1843; there are also French editions, _OEuvres
philosophiques_, by A. Garnier, 3 vols. (1834-1835), and L.
Aimé-Martin (1838) and _OEuvres morales et philosophiques_ by
Aimé-Martin with an introduction on life and works by Amedée Prévost
(Paris, 1855); _OEuvres choisies_ (1850) by Jules Simon. A complete
French edition of the collected works was begun in the Romance
Library (1907 foll.). German translations by J. H. von Kirchmann
under the title _Philosophische Werke_ (with biography, &c., Berlin,
1868; 2nd ed., 1882-1891), by Kuno Fischer, _Die Hauptschriften zur
Grundlegung seiner Philosophie_ (1863), with introduction by Ludwig
Fischer (1892). There are also numerous editions and translations of
separate works, especially the _Method_, in French, German, Italian,
Spanish and Hungarian. There are English translations by J. Veitch,
_Method, Meditations and Selections from the Principles_ (1850-1853;
11th ed., 1897; New York, 1899); by H. A. P. Torrey (New York, 1892).

II. _Biographical._--A. Baillet, _La Vie de M. Des Cartes_ (Paris,
1691; Eng. trans., 1692), exhaustive but uncritical; notices in the
editions of Garnier and Aimé-Martin; A. Hoffmann, _René Descartes_
(1905); Elizabeth S. Haldane, _Descartes, his Life and Times_ (1905),
containing full bibliography; A. Barbier, _René Descartes, sa
famille, son lieu de naissance_, &c. (1901); Richard Lowndes, _René
Descartes, his Life and Meditations_ (London, 1878); J. P. Mahaffy,
_Descartes_ (1902), with an appendix on Descartes's mathematical work
by Frederick Purser; Victor de Swarte, _Descartes directeur
spirituel_ (Paris, 1904), correspondence with the Princess Palatine;
C. J. Jeannel, _Descartes et la princesse palatine_ (Paris, 1869);
_Lettres de M. Descartes_, ed. Claude Clerselier (1657). A useful
sketch of recent biographies is to be found in _The Edinburgh Review_
(July 1906).

III. _Philosophy._--Beside the histories of philosophy, the article
CARTESIANISM, and the above works, consult J. B. Bordas-Demoulini _Le
Cartésianisme_ (2nd ed., Paris, 1874); J. P. Damiron, _Histoire de la
philosophie du XVII^e siècle_ (Paris, 1846); C. B. Renouvier, _Manuel
de philosophie moderne_ (Paris, 1842); V. Cousin, _Fragments
philosophiques_, vol. ii. (3rd ed., Paris, 1838), _Fragments de
philosophie cartésienne_ (Paris, 1845), and in the _Journal des
savants_ (1860-1861); F. Bouillier, _Hist. de la philosophie
cartésienne_ (Paris, 1854), 2 vols., and _Hist. et critique de la
révolution cartésienne_ (Paris, 1842); J. Millet, _Descartes, sa vie,
ses travaux, ses découvertes avant 1637_ (Paris, 1867), and _Hist. de
Descartes depuis 1637_ (Paris, 1870); L. Liard, _Descartes_ (Paris,
1882); A. Fouillée, _Descartes_ (Paris, 1893); _Revue de métaphysique
et de morale_ (July, 1896, Descartes number); Norman Smith, _Studies
in the Cartesian Philosophy_ (1902); R. Keussen, _Bewusstsein und
Erkenntnis bei Descartes_ (1906); A. Kayserling, _Die Idee der
Kausalität in den Lehren der Occasionalisten_ (1896); J. Iverach,
_Descartes, Spinoza and the New Philosophy_ (1904); R. Joerges, _Die
Lehre von den Empfindungen bei Descartes_ (1901); Kuno Fischer,
_Hist. of Mod. Phil. Descartes and his School_ (Eng. trans., 1887);
B. Christiansen, _Das Urteil bei Descartes_ (1902); E. Boutroux,
"Descartes and Cartesianism" in _Cambridge Modern History_, vol. iv.
(1906), chap. 27, with a very full bibliography, pp. 950-953; P.
Natorp, _Descartes' Erkenntnisstheorie_ (Marburg, 1882); L. A.
Prévost-Paradol, _Les Moralistes français_ (Paris, 1865); C.
Schaarschmidt, _Descartes und Spinoza_ (Bonn, 1850); R. Adamson, _The
Development of Modern Philosophy_ (Edinburgh, 1903); J. Müller, _Der
Begriff der sittlichen Unvollkommenheit bei Descartes und Spinoza_
(1890); J. H. von Kirchmann, _R. Descartes' Prinzipien der Philos._
(1863); G. Touchard, _La Morale de Descartes_ (1898); Lucien
Lévy-Bruhl, _Hist. of Mod. Philos. in France_ (Eng. trans., 1899),
pp. 1-76.

IV. _Science and Mathematics._--F. Cajori, _History of Mathematics_
(London, 1894); M. Cantor, _Vorlesungen über die Geschichte der
Mathematik_ (Leipzig, 1894-1901); Sir Michael Foster, _Hist. of
Physiol. during the Sixteenth, Seventeenth and Eighteenth Centuries_
(1901); Duboux, _La Physique de Descartes_ (Lausanne, 1881); G. H.
Zeuthen, _Geschichte der Mathematik im 16. und 17. Jahrhundert_
(1903); Chasles, _Aperçu historique sur l'origine et le développement
des méthodes en géométrie_ (3rd ed., 1889). (W. W.; X.)

FOOTNOTES:

[1] It was only published after the author's death; and of it, besides
the French version, there exists an English translation "by a Person
of Quality."

[2] _OEuvres_, v. 255.

[3] Ib. vi. 199.

[4]: _OEuvres_, viii. 59.

[5] Ib. viii. 173.

[6] Ib. viii. 181.

[7] Ib. vi. 123.

[8] Ib. x. 375.

[9] Ib. ix. 6.

[10] Ib. iii. 24.

[11] Ib. vi. 234.

[12] Ib. ix. 131.

[13] Ib. ix. 341.

[14] Ib. vi. 89.

[15] Ib. vi. 210.

[16] Ib. vi. 73.

[17] Ib. vi. 239.

[18] Ib. vi. 248.

[19] _OEuvres_, vi. 276.

[20] Ib. ix. 250.

[21] _Princip._ L. iii. S. 45.

[22] _OEuvres_, x. 26.

[23] _OEuvres_, x. 3.

[24] Ib. x. 53.

[25] _Regulae_, _OEuvres_, xi. 202.

[26] _OEuvres_, xi. 219.

[27] _Disc. de méthode_, part ii.

[28] _Géométrie_, book iii.

[29] _OEuvres_, xi. 224.

[30] Ib. xi. 212.

[31] _Disc. de méthode_, part. ii.

[32] _OEuvres_, xi. 243.

[33] Ib. vii. 381.

[34] _OEuvres_, vi. 132.

[35] Ib. vi. 109.

[36] _Princip._ part ii. 37.

[37] Ib. part iii. 47.

[38] _OEuvres_, iv. 494.

[39] Ib. ix. 426.

[40] Ib. x. 204.

[41] Ib. vi. 339.

[42] Ib. x. 208.

[43] Ib. iv. 452 and 454.

[44] _OEuvres_, ix. 166.

[45] _Passions de l'âme_, 36.

[46] Ib. 48.

[47] _OEuvres_, ix. 170.

DESCHAMPS, ÉMILE (1791-1871), French poet and man of letters, was born at Bourges on the 20th of February 1791. The son of a civil servant, he adopted his father's career, but as early as 1812 he distinguished himself by an ode, _La Paix conquise_, which won the praise of Napoleon. In 1818 he collaborated with Henri de Latouche in two verse comedies, _Selmours de Florian_ and _Le Tour de faveur_. He and his brother were among the most enthusiastic disciples of the _cénacle_ gathered round Victor Hugo, and in July 1823 Émile founded with his master the _Muse française_, which during the year of its existence was the special organ of the romantic party. His _Études françaises et étrangères_ (1828) were preceded by a preface which may be regarded as one of the manifestos of the romanticists. The versions of Shakespeare's _Romeo and Juliet_ (1839) and of _Macbeth_ (1844), important as they were in the history of the romantic movement, were never staged. He was the author of several libretti, among which may be mentioned the _Roméo et Juliette_ of Berlioz. The list of his more important works is completed by his two volumes of stories, _Contes physiologiques_ (1854) and _Réalités fantastiques_ (1854). He died at Versailles in April 1871. His _OEuvres complètes_ were published in 1872-1874 (6 vols.).

His brother, Antoine François Marie, known as ANTONY DESCHAMPS, was born in Paris on the 12th of March 1800 and died at Passy on the 29th of October 1869. Like his brother, he was an ardent romanticist, but his production was limited by a nervous disorder, which has left its mark on his melancholy work. He translated the _Divina Commedia_ in 1829, and his poems, _Dernières Paroles_ and _Résignation_, were republished with his brother's in 1841.

DESCHAMPS, EUSTACHE, called MOREL (1346?-1406?), French poet, was born at Vertus in Champagne about 1346. He studied at Reims, where he is said to have received some lessons in the art of versification from Guillaume de Machaut, who is stated to have been his uncle. From Reims he proceeded about 1360 to the university of Orleans to study law and the seven liberal arts. He entered the king's service as royal messenger about 1367, and was sent on missions to Bohemia, Hungary and Moravia. In 1372 he was made _huissier d'armes_ to Charles V. He received many other important offices, was _bailli_ of Valois, and afterwards of Senlis, squire to the Dauphin, and governor of Fismes. In 1380 his patron, Charles V., died, and in the same year the English burnt down his house at Vertus. In his childhood he had been an eye-witness of the English invasion of 1358; he had been present at the siege of Reims and seen the march on Chartres; he had witnessed the signing of the treaty of Bretigny; he was now himself a victim of the English fury. His violent hatred of the English found vent in numerous appeals to carry the war into England, and in the famous prophecy[1] that England would be destroyed so thoroughly that no one should be able to point to her ruins. His own misfortunes and the miseries of France embittered his temper. He complained continually of poverty, railed against women and lamented the woes of his country. His last years were spent on his _Miroir de mariage_, a satire of 13,000 lines against women, which contains some real comedy. The mother-in-law of French farce has her prototype in the _Miroir_.

The historical and patriotic poems of Deschamps are of much greater value. He does not, like Froissart, cast a glamour over the miserable wars of the time but gives a faithful picture of the anarchy of France, and inveighs ceaselessly against the heavy taxes, the vices of the clergy and especially against those who enrich themselves at the expense of the people. The terrible ballad with the refrain "_Sà, de l'argent; sà, de l'argent_" is typical of his work. Deschamps excelled in the use of the ballade and the chant royal. In each of these forms he was the greatest master of his time. In ballade form he expressed his regret for the death of Du Guesclin, who seems to have been the only man except his patron, Charles V., for whom he ever felt any admiration. One of his ballades (No. 285) was sent with a copy of his works to Geoffrey Chaucer, whom he addresses with the words:--

"Tu es d'amours mondains dieux en Albie
Et de la Rose en la terre Angélique."

Deschamps was the author of an _Art poétique_, with the title of _L'Art de dictier et de fere chancons, balades, virelais et rondeaulx_. Besides giving rules for the composition of the kinds of verse mentioned in the title he enunciates some curious theories on poetry. He divides music into music proper and poetry. Music proper he calls artificial on the ground that everyone could by dint of study become a musician; poetry he calls natural because he says it is not an art that can be acquired but a gift. He lays immense stress on the harmony of verse, because, as was the fashion of his day, he practically took it for granted that all poetry was to be sung.

The work of Deschamps marks an important stage in the history of French poetry. With him and his contemporaries the long, formless narrations of the _trouvères_ give place to complicated and exacting kinds of verse. He was perhaps by nature a moralist and satirist rather than a poet, and the force and truth of his historical pictures gives him a unique place in 14th-century poetry. M. Raynaud fixes the date of his death in 1406, or at latest, 1407. Two years earlier he had been relieved of his charge as _bailli_ of Senlis, his plain-spoken satires having made him many enemies at court.

His _OEuvres complètes_ were edited (10 vols., 1878-1901) for the
_Société des anciens textes français_ by Queux de Saint-Hilaire and
Gaston Raynaud. A supplementary volume consists of an Introduction by
G. Raynaud. See also Dr E. Hoeppner, _Eustache Deschamps_
(Strassburg, 1904).

FOOTNOTE:

[1] "_De la prophécie Merlin sur la destruction d'Angleterre qui doit
brief advenir_" (_OEuvres_, No. 211).

DESCHANEL, PAUL EUGÈNE LOUIS (1856- ), French statesman, son of Émile Deschanel (1819-1904), professor at the Collège de France and senator, was born at Brussels, where his father was living in exile (1851-1859), owing to his opposition to Napoleon III. Paul Deschanel studied law, and began his career as secretary to Deshayes de Marcère (1876), and to Jules Simon (1876-1877). In October 1885 he was elected deputy for Eure and Loire. From the first he took an important place in the chamber, as one of the most notable orators of the Progressist Republican group. In January 1896 he was elected vice-president of the chamber, and henceforth devoted himself to the struggle against the Left, not only in parliament, but also in public meetings throughout France. His addresses at Marseilles on the 26th of October 1896, at Carmaux on the 27th of December 1896, and at Roubaix on the 10th of April 1897, were triumphs of clear and eloquent exposition of the political and social aims of the Progressist party. In June 1898 he was elected president of the chamber, and was re-elected in 1901, but rejected in 1902. Nevertheless he came forward brilliantly in 1904 and 1905 as a supporter of the law on the separation of church and state. He was elected a member of the French Academy in 1899, his most notable works being _Orateurs et hommes d'état_ (1888), _Figures de femmes_ (1889), _La Décentralization_ (1895), _La Question sociale_ (1898).

DES CLOIZEAUX, ALFRED LOUIS OLIVIER LEGRAND (1817-1897), French mineralogist, was born at Beauvais, in the department of Oise, on the 17th of October 1817. He became professor of mineralogy at the École Normale Supérieure and afterwards at the Musée d'Histoire Naturelle in Paris. He studied the geysers of Iceland, and wrote also on the classification of some of the eruptive rocks; but his main work consisted in the systematic examination of the crystals of numerous minerals, in researches on their optical properties and on the subject of polarization. He wrote specially on the means of determining the different felspars. He was awarded the Wollaston medal by the Geological Society of London in 1886. He died in May 1897. His best-known books are _Leçons de cristallographie_ (1861); _Manuel de minéralogie_ (2 vols., Paris, 1862, 1874 and 1893).

DESCLOIZITE, a rare mineral species consisting of basic lead and zinc vanadate, (Pb, Zn)_2(OH)V0_4, crystallizing in the orthorhombic system and isomorphous with olivenite. It was discovered by A. Damour in 1854, and named by him in honour of the French mineralogist Des Cloizeaux. It occurs as small prismatic or pyramidal crystals, usually forming drusy crusts and stalactitic aggregates; also as fibrous encrusting masses with a mammillary surface. The colour is deep cherry-red to brown or black, and the crystals are transparent or translucent with a greasy lustre; the streak is orange-yellow to brown; specific gravity 5.9 to 6.2; hardness 3½. A variety known as cuprodescloizite is dull green in colour; it contains a considerable amount of copper replacing zinc and some arsenic replacing vanadium. Descloizite occurs in veins of lead ores in association with pyromorphite, vanadinite, wulfenite, &c. Localities are the Sierra de Cordoba in Argentina, Lake Valley in Sierra county, New Mexico, Arizona, Phoenixville in Pennsylvania, and Kappel (Eisen-Kappel) near Klagenfurt in Carinthia.

Other names which have been applied to this species are vanadite, tritochorite and ramirite; the uncertain vanadates eusynchite, araeoxene and dechenite are possibly identical with it.

DESCRIPTIVE POETRY, the name given to a class of literature, which may be defined as belonging mainly to the 16th, 17th and 18th centuries in Europe. From the earliest times, all poetry which was not subjectively lyrical was apt to indulge in ornament which might be named descriptive. But the critics of the 17th century formed a distinction between the representations of the ancients and those of the moderns. We find Boileau emphasizing the statement that, while Virgil _paints_, Tasso _describes_. This may be a useful indication for us in defining not what should, but what in practice has been called "descriptive poetry." It is poetry in which it is not imaginative passion which prevails, but a didactic purpose, or even something of the instinct of a sublimated auctioneer. In other words, the landscape, or architecture, or still life, or whatever may be the object of the poet's attention, is not used as an accessory, but is itself the centre of interest. It is, in this sense, not correct to call poetry in which description is only the occasional ornament of a poem, and not its central subject, descriptive poetry. The landscape or still life must fill the canvas, or, if human interest is introduced, that must be treated as an accessory. Thus, in the _Hero and Leander_ of Marlowe and in the _Alastor_ of Shelley, description of a very brilliant kind is largely introduced, yet these are not examples of what is technically called "descriptive poetry," because it is not the strait between Sestos and Abydos, and it is not the flora of a tropical glen, which concentrates the attention of the one poet or of the other, but it is an example of physical passion in the one case and of intellectual passion in the other, which is diagnosed and dilated on. On the other hand Thomson's _Seasons_, in which landscape takes the central place, and Drayton's _Polyolbion_, where everything is sacrificed to a topographical progress through Britain, are strictly descriptive.

It will be obvious from this definition that the danger ahead of all purely descriptive poetry is that it will lack intensity, that it will be frigid, if not dead. Description for description's sake, especially in studied verse, is rarely a vitalized form of literature. It is threatened, from its very conception, with languor and coldness; it must exercise an extreme art or be condemned to immediate sterility. Boileau, with his customary intelligence, was the first to see this, and he thought that the danger might be avoided by care in technical execution. His advice to the poets of his time was:--

"Soyez riches et pompeux dans vos descriptions;
C'est-là qu'il faut des vers étaler l'élégance,"

and:--

"De figure sans nombre égayez votre ouvrage;
Que toute y fasse aux yeux une riante image,"

and in verses of brilliant humour he mocked the writer who, too full of his subject, and describing for description's sake, will never quit his theme until he has exhausted it:--

"Fuyez de ces auteurs l'abondance stérile
Et ne vous chargez point d'un détail inutile."

This is excellent advice, but Boileau's humorous sallies do not quite meet the question whether such purely descriptive poetry as he criticizes is legitimate at all.

In England had appeared the famous translation (1592-1611), by Josuah Sylvester, of the _Divine Weeks and Works_ of Du Bartas, containing such lines as those which the juvenile Dryden admired so much:--

"But when winter's keener breath began
To crystallize the Baltic ocëan,
To glaze the lakes, and bridle up the floods,
And perriwig with wool the bald-pate woods."

There was also the curious physiological epic of Phineas Fletcher, _The Purple Island_ (1633). But on the whole it was not until French influences had made themselves felt on English poetry, that description, as Boileau conceived it, was cultivated as a distinct art. The _Cooper's Hill_ (1642) of Sir John Denham may be contrasted with the less ambitious _Penshurst_ of Ben Jonson, and the one represents the new no less completely than the other does the old generation. If, however, we examine _Cooper's Hill_ carefully, we perceive that its aim is after all rather philosophical than topographical. The Thames is described indeed, but not very minutely, and the poet is mainly absorbed in moral reflections. Marvell's long poem on the beauties of Nunappleton comes nearer to the type. But it is hardly until we reach the 18th century that we arrive, in English literature, at what is properly known as descriptive poetry. This was the age in which poets, often of no mean capacity, began to take such definite themes as a small country estate (Pomfret's _Choice_, 1700), the cultivation of the grape (Gay's _Wine_, 1708), a landscape (Pope's _Windsor Forest_, 1713), a military manoeuvre (Addison's _Campaign_, 1704), the industry of an apple-orchard (Philip's _Cyder_, 1708) or a piece of topography (Tickell's _Kensington Gardens_, 1722), as the sole subject of a lengthy poem, generally written in heroic or blank verse. These _tours de force_ were supported by minute efforts in miniature-painting, by touch applied to touch, and were often monuments of industry, but they were apt to lack personal interest, and to suffer from a general and deplorable frigidity. They were infected with the faults which accompany an artificial style; they were monotonous, rhetorical and symmetrical, while the uniformity of treatment which was inevitable to their plan rendered them hopelessly tedious, if they were prolonged to any great extent.

This species of writing had been cultivated to a considerable degree through the preceding century, in Italy and (as the remarks of Boileau testify) in France, but it was in England that it reached its highest importance. The classic of descriptive poetry, in fact, the specimen which the literature of the world presents which must be considered as the most important and the most successful, is _The Seasons_ (1726-1730) of James Thomson (q.v.). In Thomson, for the first time, a poet of considerable eminence appeared, to whom external nature was all sufficient, and who succeeded in conducting a long poem to its close by a single appeal to landscape, and to the emotions which it directly evokes. Coleridge, somewhat severely, described _The Seasons_ as the work of a good rather than of a great poet, and it is an indisputable fact that, at its very best, descriptive poetry fails to awaken the highest powers of the imagination. A great part of Thomson's poem is nothing more nor less than a skilfully varied catalogue of natural phenomena. The famous description of twilight in "the fading many-coloured woods" of autumn may be taken as an example of the highest art to which purely descriptive poetry has ever attained. It is obvious, even here, that the effect of these rich and sonorous lines, in spite of the splendid effort of the artist, is monotonous, and leads us up to no final crisis of passion or rapture. Yet Thomson succeeds, as few other poets of his class have succeeded, in producing nobly-massed effects and comprehensive beauties such as were utterly unknown to his predecessors. He was widely imitated in England, especially by Armstrong, by Akenside, by Shenstone (in _The Schoolmistress_, 1742), by the anonymous author of _Albania_, 1737, and by Goldsmith (in _The Deserted Village_, 1770). No better example of the more pedestrian class of descriptive poetry could be found than the last-mentioned poem, with its minute and Dutch-like painting:--

"How often have I paused on every charm:
The sheltered cot, the cultivated farm;
The never-failing brook, the busy mill,
The decent church that topped the neighbouring hill:
The hawthorn-bush, with seats beneath the shade.
For talking age and whispering lovers made."

On the continent of Europe the example of Thomson was almost immediately fruitful. Four several translations of _The Seasons_ into French contended for the suffrages of the public, and J. F. de Saint-Lambert (1716-1803) imitated Thomson in _Les Saisons_ (1769), a poem which enjoyed popularity for half a century, and of which Voltaire said that it was the only one of its generation which would reach posterity. Nevertheless, as Madame du Deffand told Walpole, Saint-Lambert is "_froid, fade et faux,_" and the same may be said of J. A. Roucher (1745-1794), who wrote _Les Mois_ in 1779, a descriptive poem famous in its day. The Abbé Jacques Delille (1738-1813), perhaps the most ambitious descriptive poet who has ever lived, was treated as a Virgil by his contemporaries; he published _Les Géorgiques_ in 1769, _Les Jardins_ in 1782, and _L'Homme des champs_ in 1803, but he went furthest in his brilliant, though artificial, _Trois règnes de la nature_ (1809), which French critics have called the masterpiece of this whole school of descriptive poetry. Delille, however, like Thomson before him, was unable to avoid monotony and want of coherency. Picture follows picture, and no progress is made. The satire of Marie Joseph Chénier, in his famous and witty _Discours sur les poèmes descriptifs_, brought the vogue of this species of poetry to an end.

In England, again, Wordsworth, who treated the genius of Thomson with unmerited severity, revived descriptive poetry in a form which owed more than Wordsworth realized to the model of _The Seasons_. In _The Excursion_ and _The Prelude_, as well as in many of his minor pieces, Wordsworth's philosophical and moral intentions cannot prevent us from perceiving the large part which pure description takes; and the same may be said of much of the early blank verse of S. T. Coleridge. Since their day, however, purely descriptive poetry has gone more and more completely out of fashion, and its place has been taken by the richer and directer effects of such prose as that of Ruskin in English, or of Fromentin and Pierre Loti in French. It is almost impossible in descriptive verse to obtain those vivid and impassioned appeals to the imagination which are of the very essence of genuine poetry, and it is unlikely that descriptive poetry, as such, will again take a prominent place in living literature. (E. G.)

DESERT, a term somewhat loosely employed to describe those parts of the land surface of the earth which do not produce sufficient vegetation to support a human population. Few areas of large extent in any part of the world are absolutely devoid of vegetation, and the transition from typical desert conditions is often very gradual and ill-defined. ("Desert" comes from Lat. _deserere_, to abandon; distinguish "desert," merit, and "dessert," fruit eaten after dinner, from _de_ and _servier_, to serve.)

Deserts are conveniently divided into two classes according to the causes which give rise to the desert conditions. In "cold deserts" the want of vegetation is wholly due to the prevailing low temperature, while in "hot deserts" the surface is unproductive because, on account of high temperature and deficient rainfall, evaporation is largely in excess of precipitation. Cold deserts accordingly occur in high latitudes (see TUNDRA and POLAR REGIONS). Hot desert conditions are primarily found along the tropical belts of high atmospheric pressure in which the conditions of warmth and dryness are most fully realized, and on their equatorial sides, but the zonal arrangement is considerably modified in some regions by the monsoonal influence of elevated land. Thus we have in the northern hemisphere the Sahara desert, the deserts of Arabia, Iran, Turan, Takla Makan and Gobi, and the desert regions of the Great Basin in North America; and in the southern hemisphere the Kalahari desert in Africa, the desert of Australia, and the desert of Atacama in South America. Where the line of elevated land runs east and west, as in Asia, the desert belt tends to be displaced into higher latitudes, and where the line runs north and south, as in Africa, America and Australia, the desert zone is cut through on the windward side of the elevation and the arid conditions intensified on the lee side. Desert conditions also arise from local causes, as in the case of the Indian desert situated in a region inaccessible to either of the two main branches of the south-west monsoon.