A Brief History of Modern Philosophy. Harald Høffding

should be confined to the sublunar sphere; we must rather assume that all world bodies are subject to similar conditions to those of the earth. According to Cusanus, therefore, the same principle which precludes our knowledge of Deity likewise demonstrates that the world can neither be limited nor stationary as was hitherto believed.

      2. It was characteristic of the ancient, aesthetic conception of nature to emphasize the opposition of Form and Matter. The “Forms” of natural phenomena likewise contained their explanation. Bernardino Telesius (1508-1588) introduces the concept of Force (principium agens) instead of Form (in his work De rerum natura, 1565-1587), as the opposite of Matter. He believes that this conforms more closely with the facts of experience. The “Forms” were mere qualities, which explain nothing. He rejected the traditional theory of the “natural places” and the qualitative distinction of the elements. There are as a matter of fact but two fundamental forces; the one expands (heat), the other contracts (cold), and the various “Forms” which Matter, in itself unchanging and quantitatively constant, assumes must find their explanation by reference to the interaction of these two ​forces. There are no “natural places,” for space is everywhere the same. Different places in space do not of themselves involve any qualitative differences.

      Telesius was born at Cosenza in the vicinity of Naples. His circumstances were sufficiently comfortable to provide him the opportunity to devote himself to science. He taught in the University of Naples and founded an Academy in his native city. He had planned to substitute a new theory, based on experience, for Aristotelian Scholasticism. But his critical equipment was inadequate to the accomplishment of this ideal. His general principles however mark an important advance. The details of his natural philosophy are no longer of interest. But his ideas on the psychology of knowledge still continue to be of considerable importance. He tries to bring thought and sensation into the closest possible relation. Should an object which has once been perceived in the totality of its parts and attributes recur at some later time with certain of its parts and attributes lacking, we can supply the parts which are lacking and imagine the object as a totality notwithstanding the fact that we perceive it but in part. We can imagine fire, e.g. with all its attributes, even though we only see its light, without perceiving its heat and its consuming energy. Intellection (intellegere) is the process of construing our fragmentary experience into such a totality. Even the highest and most perfect knowledge simply consists of the ability to discover the unknown attributes and conditions of phenomena by means of their similarity to other cases known as a totality. Inference simply means the recognition of the absent attributes by this method. The simplest sensory impressions are therefore related through a large number of intervening degrees to the highest ​product of scientific thought, and there is no ground for attempting to deduce our knowledge from two different sources or faculties. The problem as to whether similarity is a sensory quality like color and tone remains unsolved, as even Patrizzi, a contemporary of Telesius, charged against him.

      Telesius is inclined to ascribe sensitivity to all matter, just as, on the other hand, he regards the soul as material (with this exception, he postulated a supernatural part in the soul on theological grounds which he regarded as a forma superaddita). Every human soul, like everything else, possesses a native impulse towards self-preservation, which constitutes the foundation of ethics. Human virtues represent the various attributes which are favorable to the preservation of the individual. Wisdom is an indispensable condition which must therefore cooperate with all the other virtues (as virtus universalis). The social virtues, which are comprehended under the concept humanitas, are of great importance, because intimate association with others is a necessary condition of self-preservation. The climax of all virtue however is magnanimity (sublimitas), which finds its sufficient satisfaction in its own personal integrity and diligence. Telesius conceived his ethics in the spirit of the Renaissance, and it produced a lasting impression. His natural philosophy and his psychology were likewise very influential, especially over Bacon and Bruno.

      3. Nicholas Copernicus (Coppernick), the founder of the modern theory of the universe, was born at Thorn (1473), studied at Cracow and at various Italian Universities and was prebendary at Frauenburg, partly as Administrator, devoting part of his time to his studies. He took no part in the great controversies agitating his ​age. But he seems to have had a measure of sympathy with the religious movement, and he fell into discredit during his latter years on account of his liberal, humanistic tendency. He began the elaboration of his astronomical theory already in 1506, but he was hesitant about its publication, and the first printed copy of his work De revolutionibus orbium coelestium only appeared shortly before his death (1543). The matter which specially concerns us is the epistemological presuppositions which form the basis of this work. Two of its presuppositions must claim our attention.

      Nature always takes the simplest course. The theory of the whole universe revolving around so small a body as the earth is inconsistent with this principle. And the case is similar with the theory that the planetary orbits should not be simple circles but a very complicated system of epicycles. On the other hand, if we regard the sun as the center of the universe, and the earth and the planets as revolving around it, we have a very simple theory of the universe.

      The second presupposition is the principle of the relativity of motion previously suggested by Cusanus. The perception of motion is not adequately explained by the mere reference to the fact that a perceived object has really changed its position in space. It may likewise be due to the fact that the perceiving subject has moved. If we therefore assume that the earth, from which we observe the motion of the heavenly bodies, is itself in motion (around its axis and around the sun), we will be in position to explain the phenomenon quite as well (only more simply) as the traditional theory.

      Copernicus still adhered to the idea of a finite universe and regarded the firmament of the fixed stars, the ​boundary of the universe, as motionless. He believed the planets to be enclosed in a series of concentric permanent spheres. But notwithstanding this he prepared the way for a radical change in the theory of the universe. Facts which apparently rested on the direct evidence of sense perception and were supported by the most famous authorities must now be regarded as discredited! We must awaken to the fact that the system of things which constitutes the universe admits of a different interpretation from the apparent demands of sense perception.

      4. Giordano Bruno (1548-1600) is at once the most profound and the most courageous thinker of the renaissance period. Strongly influenced by the philosophy of antiquity and accepting the theories discovered by Cusanus and Telesius, he found a real foundation for his theory of the universe in the new astronomy, as elaborated by Copernicus and later by Tycho Brahe.

      Born at Nola in southern Italy, Bruno entered the Dominican order in his early youth. He was soon charged with heresy. His active mind and restive spirit could not endure the rigid monastic discipline. He fled the cloister, discarded the monastic garb and began a wandering career of study and travel, which took him to Switzerland, France, England and Germany. He appears in the capacity of teacher in Toulouse, Paris, Oxford and Wittenburg; but nowhere did he find a permanent position. This was due in part to the opposition of the traditional schools, and in part to his restless disposition. But despite his wanderings he found time to write his ingenious works, among which the Italian dialogues, published in London 1584, deserve special mention. He never regarded reconciliation with the Catholic church ​as impossible, and even cherished the hope of returning to Italy and, without re-entering the cloister, continuing his literary activities. He felt that his career north of the Alps was a failure and Protestantism, with its many little popes, was more reprehensible to him than the ancient church with its single Pope. He finally returned therefore, but was arrested by the Inquisition at Venice (1592) and, after a long imprisonment, burnt as a heretic at Rome in 1600. He died like a hero.

      Bruno held Copernicus in high esteem because of his lofty mind. It was he who had lifted him above the illusory testimony of the senses to which the vast majority remained enchained. But notwithstanding his unstinted admiration for the man, he nevertheless regarded the Copernican theory as inadequate because of its conception of the universe as bounded by the sphere of the fixed stars. The basis of Bruno’s opposition to this theory was two-fold, its failure to accord with his theory