 Epicurus takes to heart a problem Democritus himself recognized, which is that atomist theory threatens to undermine itself if it removes any trust we can place in the evidence of the senses, by claiming that colors, etc. are unreal. He notoriously said that ‘all perception is true,’ apparently distinguishing between the causal processes which impact our senses, all of which originate with the films of atoms sloughed off by objects, and the judgments we make on the basis of them, which may be false. Reasoning to truths about things that are not apparent—like the existence of atoms—depends on the evidence of the senses, which is always true in that it consists of impacts from actually existing films. For particular phenomena, like meteorological events, Epicurus endorses the existence of multiple valid explanations, acknowledging that we may have no evidence for preferring one explanation over another.