 Although our main witness for Epicurus’ views on the evolution of human society is Lucretius’ poem (5.925–1457), there is no doubt that Lucretius was following, in the main, the ideas of the founder himself, as recorded in Epicurus’ On Nature and other treatises. In the beginning, human beings were solitary; they reproduced haphazardly, could not communicate verbally, had no social institutions, and survived because they were physically hardier than their modern descendants. With time, the race softened, thanks in part to the discovery of fire, in part too to the emergence of the family and the gentler sentiments toward spouses and offspring to which the family gave rise. At this stage, human beings were in a position to unite in order to fend off natural dangers, such as wild beasts, and they developed various kinds of technical skills, such as agriculture and the building of houses, as well as language. Epicurus explains (LH 75–76) that names at first arose naturally, in the sense that as human beings experienced different affects (pathê) or received various images (phantasmata) they emitted air corresponding to these stimuli; since human physical characteristics vary somewhat from place to place, however, the sounds people produced in response to any given stimulus similarly differed, which explains why there are many tongues. Upon this basis, people later, nation by nation, established certain terms by convention for the purpose of improving clarity and brevity in communication. Finally, certain individual experts further augmented the vocabulary by the introduction of new and specialized words, to explain the results of their theoretical investigations. Once language reached a developed state, people began to establish alliances and friendships, which contributed further to collective security.