Le lexique de la nature : sur la notion de sponte sua chez Lucrèce

The aim of this article is to analyse the term sponte sua, which appears about twenty times in Lucretius’s poem. I begin with a commentary on Johnson’s article “Nature, Spontaneity and Voluntary Action in Lucretius”, in order to clarify my own purpose, namely, to delimit the use of sponte sua to the notion of generation in Epicurean natural philosophy and to establish its difference with respect to the voluntas. By examining a selection of passages from De rerum natura mentioning spontaneity, I conclude that this notion refers to internal causality that is opposed to both necessity and chance.