On the Nature of Things

De rerum natura (Latin: [deː ˈreːrʊn naːˈtuːraː]; On the Nature of Things) is a first-century BCE didactic poem by the Roman poet and philosopher Lucretius (c. 99 – c. 55 BCE) with the goal of explaining Epicurean philosophy to a Roman audience. The poem, written in some 7,400 dactylic hexameters, is divided into six untitled books, and explores Epicurean physics through poetic language and metaphors. Namely, Lucretius explores the principles of atomism; the nature of the mind and soul; explanations of sensation and thought; the development of the world and its phenomena; and explains a variety of celestial and terrestrial phenomena. The universe described in the poem operates according to these physical principles, guided by fortuna ("chance"), and not the divine intervention of the traditional Roman deities.

To the Greek philosopher Epicurus, the unhappiness and degradation of humans arose largely from the dread which they had of the power of the deities and terror of their wrath. This wrath was supposed to be displayed by the misfortunes inflicted in this life and by the everlasting tortures that were the lot of the guilty in a future state or, where these feelings were not strongly developed, from a vague dread of gloom and misery after death. Epicurus thus made it his mission to remove these fears, so as to establish tranquility in the minds of his readers. To do this, Epicurus invoked the atomism of Democritus to demonstrate that the material universe was formed not by a Supreme Being but by the mixing of elemental particles which had existed from all eternity, governed by certain simple laws. He argued that the deities (whose existence he did not deny) lived forever in the enjoyment of absolute peace—strangers to all the passions, desires and fears, which affect humans—and are totally indifferent to the world and its inhabitants, unmoved alike by their virtues and their crimes. This meant that humans had nothing to fear from them.

Lucretius's task was to clearly state and to fully develop these views in an attractive form. His work was an attempt to show through poetry that everything in nature can be explained by natural laws, without the need for the intervention of divine beings. Lucretius identifies the supernatural with the notion that the deities created our world or interfere with its operations in some way. He argues against fear of such deities by demonstrating, through observations and arguments, that the operations of the world can be accounted for in terms of natural phenomena, which are the result of regular but purposeless motions and interactions of tiny atoms in empty space.