The immense library of the emir was thus opened to his research. So eager and so ardent was his devotion to study, that he was accused of having set fire to the library, jealous lest another should share with him the knowledge he had gained there. An idle story.

At

But

After the death of his protector the emir, Avicenna quitted Bokhara, and extended his knowledge and his fame by visiting several great cities. He then composed his Medical Canon, which for centuries was the text-book of European schools, and is the one work by which he is known beyond his own country. He was soon again a wanderer. Hamadan the emir raised him to the post of vizir. the priests were offended, and instigated the soldiery to revolt. Avicenna was made prisoner, and his life was in danger. After some time spent in concealment, he was again able to reappear at court, and attend on the sick prince. It was at this period he composed his chief philosophical work, Al-schefá (which means The Cure; the Latin title is misleading). * And every evening he lectured on philosophy and medicine to a large and attentive audience. The lecture over, he ordered musicians to appear; and being of a festive disposition, fonder of the pleasures of the table than became a philosopher and physician, he rapidly undermined a constitution already enfeebled by over study. Avicenna was fond of wine, and on being reproached for his defiance of the Koran, replied, 'Wine is forbidden because it excites quarrels and bad passions; but I, being preserved from such excesses by my philosophy, drink wine to sharpen my intellect.'

It was a troubled life our philosopher led, crowded with excitement of various kinds. He was not content with lecturing and wine-bibbing, but must also take to conspiring. Thrown into prison, he escaped to Ispahan, where he found a new patron, with whom he passed a few years of toil and

* De his voluminibus,' says ROGER BACON, duo non sunt translata; primum autem et secundum aliquas partes habent Latini quod vocatur Assephæ, i.e. Liber Sufficientiæ.'-Opus Tertium.

excitement, which terminated in 1037, in the fifty-seventh year of his age.

The immense productivity of the ancient philosophers is one of their most striking characteristics. Avicenna, whose brief career was also a troubled one, found time to be as voluminous as a Benedictine. Learned in all the learning of his time (which however was easily compassed), he composed more than a hundred works, some of which still survive.*

In the eleventh century he was to the Mohammedans of the East what, in the twelfth century, Averroes was to the Mohammedans of the West, and what Albertus Magnus was to Europe in the thirteenth century. Indeed, it is very probable, as M. Jourdain suggests,† that Albertus borrowed the plan of his own vast labours from Avicenna, who was not so much a translator or commentator of Aristotle, as the popularizer and propagator of his ideas. Like Albertus, he composed treatises on all the subjects treated by the Stagirite, often reproducing the expressions as well as the ideas of his model, but not unfrequently deviating into new tracks, either because he had misinterpreted the original, or because his own wider knowledge and clearer thought enabled him to improve it. His least questionable improvements were in psychology. It is to Avicenna that the Arabs, and after them the Schoolmen, owe the classification of the faculties into exterior (the five senses), interior, motor, and rational.

The immense and enduring success of Avicenna's Medical Canon is a significant fact, when we reflect that he had not alvanced the science in any one direction beyond the point

• A Latin version, publi-hed at Venice in 1495, under this title-Avicennæ, peripatetics philosophi ac medicorum facile primi, opera in lucem redacta ac nuper guration are niti potuit, per canonicos emendata-contains Logica, Sufficientia (or, as we should style it, Physica), De Calo et Mundo, De Animâ, De Animalibus, De Iret"-gentre, Lipharabius de Intelligentis, and Philosophia Prima.

✦ JotuDain: Recherches sur les anciennes traductions latines d'Aristote. Paris, 1×43, p 209.

Princeps magnus, qui semper in libris sapientiæ vocatur princeps Abholati, is iterum revocavit philosophiam in Arabico, et exposuit opera antiquorum.' ROGER BACON: Opus Tertium, cviii. p. 24.

it had reached among the Greeks. Nay, in some respects it was even less advanced, for it servilely followed Aristotle in preference to Galen, and this, too, in simple matters of fact within easy verification; such, for example, as in assigning only three chambers to the heart. The Arabs could have no scientific pre-eminence over the Greek physicians, for they were by Mohammedan prejudices forbidden to practise human anatomy; and consequently physiology inevitably became a mere display of teleological ingenuity.

Sprengel asks how it is that the Canon came to secure and preserve its unquestioned supremacy in European schools, not being really superior to other Arabian works on the same subject. He finds an explanation in the systematic completeness of the work, and the indolent servility of the public, which was flattered by that cut-and-dried wisdom. These men,' he says, 'disliked novelties; accustomed in religious matters to obey without scruple the infallible dicta of the Church, it was agreeable to them to have an infallible authority in matters of science.'* Authority has always had great weight in Medicine; and the reason is because positive science plays so small a part in it. Where men cannot appeal to proofs, they must fall back on precedents; where they lack reasons there they quote authorities. Avicenna gratified the disposition to accept authority, and gratified the indolence which shrinks from laborious research. His dicta rendered research superfluous. Men were little given to independent thought in those days, when Science meant the knowledge of what other men had thought. The Canon contained the chief thoughts of Greek and Arabic sages; and men were thus saved even from the labours of erudition; for why should they have sought in the originals what this compendium so conveniently placed within easy reach? It was not until they began to think of interrogating Nature, instead of echoing the sages, that Avicenna's supremacy was disputed. And so naturally servile is the human intellect, so reluctantly does it withhold allegiance from a name which has once held *SPRENGEL: Gesch. der Arzneikunde. Halle, 1823, II. 424.

authority, that even late in the sixteenth century we find Scaliger asserting that no man could be an accomplished physician who had not mastered Avicenna.

Following a chronological order, two names ought to be interposed here, Avicebron and Algazzali; but for purposes of exposition, I withhold these till a subsequent page, Algazzali being better understood in connection with Averroes, and Avicebron conducting us back to the scholastics.

§ IV. AL-HAZEN.

Al-Hazen ('Abou 'Ali al'Hasan ben al-'Hazen) was really a distinguished mathematician, who flourished during the early part of the eleventh century. He is best known in Europe by his treatise on Optics, translated by Risner, and published at Bâle in 1572. He therein corrected the Greeks, who supposed that rays of light issue from the eye and impinge on the objects; by anatomical and geometrical arguments, he shows that the rays come from the objects and impinge on the retina. He further explained the fact, that we see objects singly, though with two eyes, because the visual images are formed on symmetrical portions of the two retinas. He explains reflection and refraction; and astonishes us with his knowledge that the atmosphere increases in density as it decreases in height, and that the path of a ray of light through it, on entering obliquely, must be curvilinear and concave to the earth. Hence, as the mind refers the position of an object to the direction in which the ray of light enters the eye, the stars must appear to us nearer the zenith than they really are. Hence we see the stars before they have arisen and after they have set.*

SV. AVEMPACE.

Avempace, as the West called Abou Beer Mohammed ben Yahya Ibn Badja, is one of the most celebrated of the Spanish Mohammedans. He flourished early in the twelfth century.

It is eminently probable that KEPLER borrowed his optical views from AL-HAZEN. It is certain that he has no just title to originality as the discoverer, with is sometimes claimed for him.

He is the first of his compatriots in Spain who attained celebrity as a philosopher; and according to Ibn Tofail, his illustrious successor, he surpassed all contemporaries in depth of wisdom, although worldly affairs and a premature death prevented the completion of those important works which he had designed. He only published hastily written essays on Mathematics, Medicine, and Philosophy, and commentaries on Aristotle. One of his antagonists thought it a severe sarcasm to say, that he only studied mathematical science, only meditated on the heavenly bodies and on the nature of climate, despising the Koran, which in his arrogance he sets aside.' The same critic, with the common candour of critics, says, according to him it is better to do evil than good, and that beasts are better guided than men.' Munk, who gives an analysis of one of Avempace's works,* says that he impressed on Arabian Philosophy a movement directly opposed to the mystical tendencies of Algazzali, and 'qu'il proclama la science spéculative seule capable d'amener l'homme à concevoir son propre être ainsi que l'intellect actif.'

§ VI. ABUBACER.

Early in the twelfth century appeared Abou Beer Mohammed ben-'Abd-al-Malic Ibn Tofail, known in Europe as Abubacer. He was born in Andalusia; and was renowned at the court of the Almohades for his skill as a physician and poet, and for his mathematical and philosophical learning. After having filled the office of secretary to the governor of Granada, he was appointed vizir and physician to Yousouf, the second king of the Almohade dynasty, who admitted him to great intimacy. His favour at court was honourably employed in protecting other savants, and it was he who presented Averroes to the king; showing a sublime superiority to any of those movements of jealousy which disturb inferior minds. One day, Yousouf expressed a desire to have a clear analysis of Aristotle's doctrine. Abubacer urged the task upon Averroes, instead of undertaking it

*MUNK: Op. cit. pp. 389-409.