Lucretius wanted his poetry to convey the scientific truths of Epicurean doctrine. In addition, he thought that one single generative and organic principle unites atomistic physics and the combinatory production of meaning. Thanks to the interplay between its “outer metric” (the distribution of dactylic/spondaic feet and caesuras) and its “inner metric” (the collocation of metrical word-types), the Latin hexameter allowed him to create intricate networks of similarities and differences, aimed at expressing the central tenets of the Epicurean system in such a way that they acquire the “evidence” of sensory impressions. As shown by the detailed analysis of two excerpts (II, 308-332; I, 1-20), systematic choices operating at the level of both “outer” and “inner” metrics provide a mimetic representation of the very essence of Epicurean reality, whose constant change and movement produce order and complexity based on the functional properties of its pro-forms.