Atomic atheism in verse.

Lucretius (Titus Lucretius Carus) lived ca. 99–ca. 55 BC, but the details of his career are unknown. He is the author of the great didactic poem in hexameters, De Rerum Natura (On the Nature of Things). In six books compounded of solid reasoning, brilliant imagination, and noble poetry, he expounds the scientific theories of the Greek philosopher Epicurus, with the aim of dispelling fear of the gods and fear of death and so enabling man to attain peace of mind and happiness.

In Book 1 he establishes the general principles of the atomic system, refutes the views of rival physicists, and proves the infinity of the universe and of its two ultimate constituents, matter and void. In Book 2 he explains atomic movement, the variety of atomic shapes, and argues that the atoms lack color, sensation, and other secondary qualities. In Book 3 he expounds the nature and composition of mind and spirit, proves their mortality, and argues that there is nothing to fear in death. Book 4 explains the nature of sensation and thought, and ends with an impressive account of sexual love. Book 5 describes the nature and formation of our world, astronomical phenomena, the beginnings of life on earth, and the development of civilization. In Book 6 the poet explains various atmospheric and terrestrial phenomena, including thunder, lightning, earthquakes, volcanoes, the magnet, and plagues.

The work is distinguished by the fervor and poetry of the author.

In this first comprehensive study of the effect of Lucretius's De rerum natura on Florentine thought in the Renaissance, Alison Brown demonstrates how Lucretius was used by Florentine thinkers—earlier and more widely than has been supposed—to provide a radical critique of prevailing orthodoxies.

To answer the question of why ordinary Florentines were drawn to this recently discovered text, despite its threat to orthodox Christian belief, Brown tracks interest in it through three humanists—the most famous of whom was Machiavelli—all working not as philologists but as practical administrators and teachers in the Florentine chancery and university. Interpreting their direct use of Lucretius within the context of mercantile Florence, Brown highlights three dangerous themes that had particular appeal: Lucretius's attack on superstitious religion and an afterlife; his pre-Darwinian theory of evolution; and his atomism, with its theory of free will and the chance creation of the world.

The humanists' challenge to established beliefs encouraged the growth of a "Lucretian network" of younger, politically disaffected Florentines. Brown thus adds a missing dimension to our understanding of the "revolution" in sixteenth-century political thinking, as she enriches our definition of the Renaissance in a context of newly discovered worlds and new social networks.