opinion, reputation
Opinion (δόξα) is one of the soul's cognitive powers (δύναμις), holding an intermediate position between knowledge (ἐπιστήμη) and ignorance (ἄγνοια). In the Republic Socrates shows that knowledge is by nature set over what is (τὸ ὄν), ignorance over what is not (τὸ μὴ ὄν), while opinion is directed at what partakes of both being and not-being—at the intermediate (τὸ μεταξύ)—and therefore itself lies "between" knowledge and ignorance (Resp. V 478d). As a power, opinion is "darker than knowledge but clearer than ignorance" (Resp. V 478c) and, unlike infallible knowledge, can be either true or false.
In the Meno true opinion (ἀληθὴς δόξα) leads to right action no less than knowledge does; yet it is held insecurely in the soul and, like the "statues of Daedalus," "runs away" until it is "bound by reasoning about the cause" (αἰτίας λογισμός)—and this binding is what turns opinion into knowledge (Men. 97e–98a). The Theaetetus, in turn, tests and rejects the definitions that identify knowledge with opinion: neither true opinion (Tht. 187b) nor true opinion "with an account" (μετὰ λόγου, Tht. 201d) proves to be knowledge—opinion remains below the strict λόγος that gives an account of the essence.
In the Sophist δόξα is defined directly through λόγος: it is the concluding affirmation (κατάφασις) or denial (ἀπόφασις) of that voiceless speech which the soul carries on with itself—opinion is "the completion of thought" (Soph. 264a–b). Opinion is thereby built into the very circle of logos: it can be true or false just as λόγος can be true or false, and it shares with λόγος a relation to falsehood (ψεῦδος). The core connections of doxa are knowledge (ἐπιστήμη), true opinion (ἀληθὴς δόξα), ignorance (ἄγνοια), perception (αἴσθησις), and becoming (γένεσις); opinion stands opposed to strict knowledge and to the grounded λόγος toward which the ascent from δόξα to intellect (νοῦς) leads.