Renaissance Cosmology: Second Stage

Giordano Bruno

Catholics and Protestants united to reject Copernicus’ doctrines as heretical, and his immediate successors in astronomy refused to accept his system in its strictly astronomical bearing. But its philosophical importance lay in the fact that its main thesis implied an homogeneity of substance between the earth and the heavenly bodies, and an identity in the laws governing their movement; and these implications were quickly welcomed by a new group of thinkers to whom belongs the credit of initiating the second and final stage in the Renaissance theory of nature. The most important figure of this group is Giordano Bruno.

Bruno, born in 1548, and becoming a Dominican friar early in life, was already obliged to leave Italy under an accusation of heresy before he was thirty, and lived successively at Geneva, Toulouse, Paris, London, Wittenberg, and elsewhere. He returned to Italy to take up his residence at Venice under the protection of the Doge Giovanni Mocenigo, but was seized by the Inquisition there and tried at Rome over a period of seven years (1593-1600), and was finally burnt at the stake.

Bruno’s most important contribution to the theory of nature consisted in his philosophical interpretation of Copernicanism. He realized that the new astronomy, which he accepted with enthusiasm, implied a denial of any qualitative difference between terrestrial and celestial substance. He extended this denial, as Copernicus had never done, from a solar or planetary system to that of the fixed stars, admitting only one kind of distinction, namely that between fiery or luminous bodies and translucent or crystalline; all move according to the same laws, with an inherent circular motion, and the Aristotelian conceptions of natural heaviness and lightness are rejected. There is no first mover external to the material world; movement is intrinsic and natural to body as such. The material world is conceived as an infinite space, not empty but full of a yielding and plastic matter which recalls to our minds the ether of more modern physics; in this ether are innumerable worlds like ours, forming in their totality a universe not itself changing or moving but containing all change and movement within itself. This all-embracing and unchanging substance, the matrix of all change, is at once matter, in its capacity as extended and moving, and form or spirit or God, in its capacity as self-existent and the source of movement; but it is not a transcendent unmoved mover like the god of Aristotle but a mover immanent in its own body and causing movements throughout that body. Thus every particular thing and every particular movement has, in Bruno’s language, both a principle, or a source within itself, and a cause, or source outside itself; God is both principle and cause, principle as immanent in each individual part of nature, cause as transcending each individual part.

This pantheistic cosmology reminds us on the one hand of the later Ionians, and on the other hand of Spinoza. It is like Anaximander in conceiving our world as one of an infinite number of vortices in an infinite homogeneous primary matter extending throughout infinite space, and in conceiving this matter as identical with God. Just as the pantheism of Anaximander gave way, as Greek thought developed, to a doctrine according to which the world is not God but God’s creature, so Bruno’s pantheism gave way to a doctrine according to which the world is not divine but mechanical, implying therefore a transcendent God who designed and constructed it. The idea of nature as a machine is fatal to monism. A machine implies something outside itself. The identification of nature with God breaks down exactly when the organic view of nature disappears.

On the other hand, Bruno’s thought resembles Spinoza’s in so many ways that it has been described as stopping short of Spinoza’s complete position only because Bruno was an unsystematic and desultory thinker, richer in passion and intuition than in method and logical perseverance. But this is not the whole truth. Spinoza’s cosmology presupposes the whole mechanistic theory of the universe, which Bruno’s has not yet envisioned. The great feat of Spinoza is to bring together two conceptions which in Bruno are not yet distinguished, the conception of a world of mechanical matter and the conception of a world mind, as these were worked out separately by Descartes.

Bruno’s synthesis of the two ideas of principle and cause is only apparent. By principle he means immanent cause, causa sui: by cause he means transient cause, where A is the cause of B. In terms of pantheism, the world which is also God is, taken as a whole, the cause of itself; but the cause of any particular event is not the world as a whole but some other particular event. For the whole does not transcend this or that part of it; it is immanent in this or that part; what transcends any one part can only be another part. To speak of the whole as transcending a part is to degrade the whole to the status of one of its own parts. In order to clear up this confusion, Bruno would have had to take one decisive step which he never took, that is to say namely that, abandoning the conception of nature as an organism and developing the conception of nature as a machine.