Abstract
In Epicureanism, the ‘atom’ is the fundamental element of reality. There is a finite number of different atom shapes, but an infinite number of each shape, which move and congregate in a void of infinite extent. ‘Atomic worlds’ considers how Epicureans came to believe in this ontology and then discusses its doubters, including Parmenides, Aristotle, and Cicero, who believed the Epicurean thesis of the multiplicity of worlds and their ongoing creation and destruction were absurd. The early modern rediscovery of atomism contributed significantly to the Scientific Revolution of the 17th century, but despite contemporary physical science retaining some elements of the Epicurean image of nature, it is now known that atoms are not the smallest, fundamental particles.