V. Copernicus and Later Thinkers

Not a century after Cusanus, in 1543, Nicolaus Coper- nicus (1473-1543) expounded the theory that the earth revolves round the sun, though he did not extend his con- clusions, which he drew from mathematical considerations, to the sidereal heavens. Bruno got hold of Copernicus' work.^ Probably it was in the monastic library ; for it had been dedicated to Paul III at the entreaty of friends who feared what might otherwise follow, and one Osiander, a priest of Nuremberg, wrote a preface, in which he protests that the work is not presented as truth, but because it furnishes improved practical utility for astronomical com- putation.8 Bruno knew that this mendacious apology for speaking the truth was not written by Copernicus, who had asserted his right to deal with the problem in his own way.* The thoughtful pondered over Copernicus' book, perceiving that he had applied Ockham's razor and dealt a blow to the bad method of multiplying hypotheses to explain observed facts of the same kind. It was irrational to suppose that Nature does not proceed straight to her goal. The new theory administered a shock to the fashionable Aristotelian physics and cosmogony, built on sense-per- ceptions, and, in time, it came to be heartily accepted and extended by Bruno, who had so early begun to doubt the
• Cusanus ; De venatio sapienticz.
^ Copernicus ; De orbium ccelestium revolutionibus. ' It is obvious that Osiander was no pragmatist !
* Bruno ; Cena, Dial. Ill, Seconda prop, di Nundinio.
32 GIORDANO BRUNO
deliverances of sensation. There was general resistance to the new view. Those with the spirit of the Renaissance in them felt that a blow was struck at their exaltation of humanity; the pious opined that the fall of the official science of the Church might bring down much more. For Bruno, the vivid and realistic pictures of Dante were re- placed by another kind of realism, colder perhaps, but only colder to the unimaginative, appealing less, perhaps, to ordi- nary human sympathy, but far more powerfully to intel- lectual vision. He was prepared to trust Reason and follow her whithersoever she might lead ; and he saw that, if the importance of man as a being was diminished, his intellect, which could hold the whole solar system in its grasp, gained infinitely in dignity.
Bruno read " The Nature of Things," by Bernardino Telesio (1509-1588). Local patriotism would prepare him to appreciate the writings of a man who, born at Cozena, had founded the Cosentina Academy at Naples. Telesio insisted on the importance of observation and took for his motto, " not by reason, but by sense." But he admitted that the mind co-operates with sensation.^ Bruno calls him " the most judicious Telesio." 2 Girolamo Cardano (1501-1576) was another writer whom Bruno valued for his appreciation of physical enquiry. He used much super- stitious information which can be traced to Cardano, or to the writings of that half-mad genius in motley, Aureol Theophrast Paracelsus (1490-1541). Paracelsus attracted Bruno because of his attempt to determine the chemical constitution of things ; because he held all creatures to be emanations from a world-soul,* and because he taught a doctrine deduced from this, that throughout the whole choir
' Telesius ; De rerum natura. Cfr. Sensini, T ; Sul fiensiero filosofico di G. B., 1907,/. 13.
2 Causa, Dial. III. » Bruno ; Causa, Dial. III.
DISCIPLINE OF BOOKS 33
of heaven and furniture of earth there exists a subtle sympathy. Although Pietro Angelo Manzoli (Palingenius) held the universe to be infinite, he did not produce much effect on Bruno. Indeed, it seems doubtful whether Bruno ever read this Ferrarese poet, for he speaks of him as being a German.^
Bruno was vastly interested in the mathematics of his day, and, later, gave the subject much thought and evinced considerable originality in it, sometimes of a mistaken kind.* Indeed, like Bacon he had " taken all knowledge to be his province." Most of his acquisitions must have been made during the quiet years at Naples. Henceforth he was a wanderer, earning his bread ; and what small leisure befell him was given up to creative work.
' Oratio Valedic. For the effects of these later writers on Bruno's mind and work, see Tocco, F ; Fonti phi recenti dellaf. del B., Acad, dei Lincei, Rendiconii ser.,j,pp. 503 sgg; 585 sgq.
^ Cfr. J. B. Nolani Articuli centum et sexaginta adversus mathe- maticos ; De monadej De tripUci minivio.