GIORDANO BRUNO. 251 the infinite power of God by means of the position already established that in God act and possibility coincide. If one attribute of God were finite, then, it is said, all would be finite. Those who maintain that the universe of matter and space is absolutely limited must be asked by what they suppose it to be limited. If they say by an immaterial world or principle, then it must be replied that a material and an immaterial world cannot form one continuum. Be- yond the world in which we live nothing can exist but ethereal space and other worlds of similar composition. From the infinity of the universe of matter and space it follows that it can be acted upon by no cause external to itself. In this way Bruno connects his metaphysics with the cos- mology which he substitutes for that of the Peripatetics. At the same time he attacks the Aristotelian physics and the Ptolemaic astronomy on purely scientific grounds. The hypotheses of mathematicians have, he says, been put in place of reality. But nature ought to be a law to reason, not reason to nature. To those who appeal to the evidence of the senses in favour of the received opinions, he says that it is really from " an imbecility of the reason " that these opinions proceed, and not from the senses. The senses do not deceive ; truth and falsehood are in propositions, not in the elements that sense supplies to reason. Sense itself, rightly considered, suggests the notion of an infinite uni- verse ; for we have experience of the illusory character of limits such as the visible horizon, and of the appearances of things at a distance. The hypothesis of an eighth sphere containing all the fixed stars is compared to the opinion of one who, being surrounded by trees, should think the seven nearest to be unequally and all the rest equally distant from him because they appear so. The repugnancy of the Peri- patetic doctrine of the motion of the heavenly bodies in perfect circles to all that is observed of nature is frequently dwelt on. According to Bruno, though all natural processes are in a sense circular, nothing ever returns precisely to its former state. He ridicules the fancy of the Platonic year, regarding it as a kind of symbol of the opinion that mathe- matical exactness is observed by nature. He affirms that no mathematical circle exists in nature, any more than a mathematical point or straight line. Each of the planets has one motion which may be resolved into a number of approximately circular motions, but which is itself neither motion in a circle nor in any combination of circles. The heavenly bodies move freely in infinite space ; they are not
