 5.416–770. Following up on this theme, Lucretius now reconstructs the blind process of atomic conglomeration that gave rise to our world. He then continues with a matchingly non-theistic series of explanations of individual celestial phenomena. In true Epicurean spirit (here and in book 6 too; see especially 6.703–11), his favoured policy is to list a plurality of explanations of one and the same phenomenon without selecting one as correct. What matters is that, however many such explanations we acknowledge, they should be exclusively material explanations sufficient to render unnecessary the postulation of divine intervention. Being intrinsically possible, they must also be true, if not in our world, then at any rate somewhere, for in an infinite universe no possibility can remain unactualized (an application of the Principle of Plenitude). Lucretius is here relying on an Epicurean modal theory based on  actual—not just possible—worlds, whereby ‘possible’ is equated with ‘true in one or more (actual) worlds’, ‘necessary’ with ‘true in all (actual) worlds’.