 Within space God places matter that in clear contrast to the conception of Aristotle and Averroes, who defined it as privation and as a pure ens rationis, is regarded by Campanella as a physical entity, deprived of form, shape and action, but capable of being extended, divided, united and of assuming any shape, just as wax can receive an impression from any seal. Into this corporeal mass God inserts heat and coldness, the two active principles, that are self-disseminating and incorporeal but can only subsist in bodies. From their conflict, deriving from the fact that each wants to take possession of and occupy the greatest possible quantity of matter, come the two primary bodies and elements of the world: the heavens, that are extremely hot, subtle and mobile, since they are formed of matter transformed by heat; and the earth, composed of matter made immobile, dark and dense by cold. The clash between the heavens and the earth, between heat and coldness—instruments and ‘craftsmen’ that God uses to produce the infinite modes of his creative wisdom in the wondrous effigy that is the world—gives birth to all individual entities. By means of these principles Campanella explains every aspect of the natural world, from celestial and meteorological phenomena to the formation of the waters, from the composition of minerals to that of plants. Animals and human beings he analyzes with particular attention. At the origin of these organisms, that are more complex and have more parts, lies an especially attenuated celestial heat, the spiritus. Consisting of matter made extremely subtle by solar heat, it is a warm breath that, thanks to its tenuousness and motion, is able to separate itself from the portion of matter in which it finds itself enclosed and to act on it. Unable to exhale itself from corporeality in order to return to the heavens from which it has its origin, this plasma constructs, in ways that suit its needs and avoid the external dangers threatening it from within, the organs that guarantee its conservation and life. Proud of his medical knowledge (among his works is one entitled Medicina, made up of eight books and published in Lyons in 1635), here and in other treatises Campanella delighted in highlighting the wondrous structure of the human body and its parts, revealing how the functions and purposes specific and particular to individual organs harmonize in the marvelous order of the totality and confirm the presence of divine craftsmanship in every fiber of natural reality.