Editing Democritus (section)

===Epistemology===
It was very natural, given his theory or perception, that Democritus described even the knowledge obtained by sensuous perception as obscure (σκοτίην κρίσιν). A clear and pure knowledge is only that which has reference to the true principles or the true nature of things, that is, to the atoms and space. But knowledge derived from reason was, in his opinion, not specifically different from that acquired through the senses; for conception and reflection were to him only effects of impressions made upon the senses; and Aristotle, therefore, expressly states, that Democritus did not consider mind as something peculiar, or as a power distinct from the soul or sensuous perception, but that he considered knowledge derived from reason to be sensuous perceptions.<ref>De Anim. 1.2. p. 404, 27.</ref> A purer and higher knowledge which he opposed to the obscure knowledge obtained through the medium of the senses, must therefore have been to him a kind of sensation, that is, a direct perception of the atoms and of space. For this reason he assumed the three criteria (κριτήρια) : a. Phaenomena as criteria for discovering that which is hidden : b. Thought as a criterion of investigation : and c. Assertions as criteria of desires.<ref>Sext. Emp. ad v. Math. 7.140; Brandis, l.c. p. 334.</ref> Now as Democritus acknowledged the uncertainty of perceptions, and as he was unable to establish a higher and purely spiritual source of knowledge as distinct from perceptions, we often find him complaining that all human knowledge is uncertain, that in general either nothing is absolutely true, or at least not clear to us,<ref>(ἄδηλον, Aristot. Metaph. Γ. 5)</ref> that our senses grope about in the dark,<ref>sensus tenebricosi, Cic. Ac. 4.10, 23</ref> and that all our views and opinions are subjective, and come to us only like something epidemic, as it were, with the air which we breathe.<ref>Sext. Emp. ad v. Math. 7.136, 137, 8.327, Hypotyp. 1.213 ; D. L. 9.72, ἐτεῇ δ᾽ οὐδὲν ἴδμεν, ἐν βυθῷ γὰρ ἡ ἀλ́ηεια, which Cicero translates in profundo veritatem esse.</ref><ref>{{cite DGRBM|title=Democritus|url = https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0104%3Aentry%3Ddemocritus-bio-2}}</ref>