Raymundus Lullus, the _Doctor illuminatus_, made himself famous chiefly by the art of thinking which he invented, which was called the _ars magna_. He was born at Majorca in 1234, and was one of those eccentric, unsettled natures whose activity finds vent in all directions. He had a strong inclination towards alchemy and great enthusiasm for the sciences in general, as well as a fiery, restless power of imagination. In his youth he led a reckless life, throwing himself headlong into a round of pleasures; then he retreated to a desert, and had there many visions of Jesus. At this time the impulse shaped itself in his ardent nature to dedicate his life to spreading the blessings of Christianity among the Mohammedans in Asia and Africa. In order to carry on this work of conversion he learned Arabic, travelled through Europe and Asia, sought for assistance from the Pope and all the crowned heads of Europe, without giving up, for all that, his interest in his ‘Art.’ He suffered persecution and passed through many hardships and strange adventures, perils of death, imprisonments, cruelties. He lived long in Paris at the beginning of the fourteenth century, and was the author of well-nigh four hundred works. After a life of the utmost restlessness, he died in 1315, revered as a saint and martyr, his death being the result of cruel treatment which he had suffered in Africa.[53] The chief object aimed at in this man’s ‘Art’ was an enumeration and arrangement of the various concepts under which all objects fall, or of the pure categories according to which they can be determined, so that it may be possible in regard to every object to indicate with ease the conceptions applicable to it. Lullus is so systematic that he becomes at times mechanical. He constructed a diagram in circles, on which were marked triangles through which the circles pass. In these circles he arranged the various concepts, and strove to give a complete catalogue of them. Some of the circles were fixed, others movable, and they were six in number, two of them indicating the subjects, three the predicates, while the outermost circle represented possible questions. For each class he had nine qualities, to indicate which he chose nine letters, B C D E F G H I K. Thus in the first place he wrote round the diagram nine absolute predicates, goodness, greatness, duration, power, wisdom, volition, virtue, truth, splendour; then he wrote nine relative predicates, diversity, unanimity, opposition, beginning, middle, end, the qualities of being greater, equal, or less; in the third place he set down the questions Whether? What? Whence? Why? How great? Of what nature? When? Where? How and wherewith? the ninth of which contains two determinations; in the fourth place he put nine substances (_esse_), viz. God (_divinum_), angel (_angelicum_), heaven (_cæleste_), man (_humanum_), _imaginativum_, _sensitivum_, _vegetativum_, _elementativum_, _instrumentativum_; in the fifth place were nine