The Gospel of John identifies the Christian Logos, through which all things are made, as divine (theos), and further identifies Jesus Christ as the incarnate Logos. Early translators of the Greek New Testament such as Jerome (in the 4th century AD) were frustrated by the inadequacy of any single Latin word to convey the meaning of the word logos as used to describe Jesus Christ in the Gospel of John. The Vulgate Bible usage of in principio erat verbum was thus constrained to use the (perhaps inadequate) noun verbum for "word", but later Romance language translations had the advantage of nouns such as le mot in French. Reformation translators took another approach. Martin Luther rejected Zeitwort (verb) in favor of Wort (word), for instance, although later commentators repeatedly turned to a more dynamic use involving the living word as felt by Jerome and Augustine. The term is also used in Sufism, and the analytical psychology of Carl Jung.
Despite the conventional translation as "word", it is not used for a word in the grammatical sense; instead, the term lexis (λέξις, léxis) was used. However, both logos and lexis derive from the same verb légō (λέγω), meaning "(I) count, tell, say, speak".
The writing of Heraclitus (c. 535 – c. 475 BC) was the first place where the word logos was given special attention in ancient Greek philosophy, although Heraclitus seems to use the word with a meaning not significantly different from the way in which it was used in ordinary Greek of his time. For Heraclitus, logos provided the link between rational discourse and the world's rational structure.
This logos holds always but humans always prove unable to ever understand it, both before hearing it and when they have first heard it. For though all things come to be in accordance with this logos, humans are like the inexperienced when they experience such words and deeds as I set out, distinguishing each in accordance with its nature and saying how it is. But other people fail to notice what they do when awake, just as they forget what they do while asleep.
What logos means here is not certain; it may mean "reason" or "explanation" in the sense of an objective cosmic law, or it may signify nothing more than "saying" or "wisdom". Yet, an independent existence of a universal logos was clearly suggested by Heraclitus.
Aristotle identifies two specific types of persuasion methods: artistic and inartistic. He defines artistic proofs as arguments that the rhetor generates and creates on their own. Examples of these include relationships, testimonies, and conjugates. He defines inartistic proofs as arguments that the rhetor quotes using information from a non-self-generated source. Examples of these include laws, contracts, and oaths.
Aristotle's rhetorical logos
Aristotle, 384–322 BC.
Following one of the other meanings of the word, Aristotle gave logos a different technical definition in the Rhetoric, using it as meaning argument from reason, one of the three modes of persuasion. The other two modes are pathos (πᾰ́θος, páthos), which refers to persuasion by means of emotional appeal, "putting the hearer into a certain frame of mind"; and ethos (ἦθος, êthos), persuasion through convincing listeners of one's "moral character". According to Aristotle, logos relates to "the speech itself, in so far as it proves or seems to prove". In the words of Paul Rahe:
For Aristotle, logos is something more refined than the capacity to make private feelings public: it enables the human being to perform as no other animal can; it makes it possible for him to perceive and make clear to others through reasoned discourse the difference between what is advantageous and what is harmful, between what is just and what is unjust, and between what is good and what is evil.
Logos, pathos, and ethos can all be appropriate at different times. Arguments from reason (logical arguments) have some advantages, namely that data are (ostensibly) difficult to manipulate, so it is harder to argue against such an argument; and such arguments make the speaker look prepared and knowledgeable to the audience, enhancing ethos. On the other hand, trust in the speaker—built through ethos—enhances the appeal of arguments from reason.
Robert Wardy suggests that what Aristotle rejects in supporting the use of logos "is not emotional appeal per se, but rather emotional appeals that have no 'bearing on the issue', in that the pathē [πᾰ́θη, páthē] they stimulate lack, or at any rate are not shown to possess, any intrinsic connection with the point at issue—as if an advocate were to try to whip an antisemitic audience into a fury because the accused is Jewish; or as if another in drumming up support for a politician were to exploit his listeners's reverential feelings for the politician's ancestors".
Aristotle comments on the three modes by stating:
Persuasion is clearly a sort of demonstration, since we are most fully persuaded when we consider a thing to have been demonstrated. Of the modes of persuasion furnished by the spoken word there are three kinds. ... Persuasion is achieved by the speaker's personal character when the speech is so spoken as to make us think him credible. ... Secondly, persuasion may come through the hearers, when the speech stirs their emotions. ... Thirdly, persuasion is effected through the speech itself when we have proved a truth or an apparent truth by means of the persuasive arguments suitable to the case in question.[whose translation?]
The Pyrrhonist philosopher Sextus Empiricus defined the Pyrrhonist usage of logos as "When we say 'To every logos an equal logos is opposed,' by 'every logos' we mean 'every logos that has been considered by us,' and we use 'logos' not in its ordinary sense but for that which establishes something dogmatically, that is to say, concerning the non-evident, and which establishes it in any way at all, not necessarily by means of premises and conclusion."
Stoic philosophy began with Zeno of Citiumc. 300 BC, in which the logos was the active reason pervading and animating the Universe. It was conceived as material and is usually identified with God or Nature. The Stoics also referred to the seminal logos ("logos spermatikos"), or the law of generation in the Universe, which was the principle of the active reason working in inanimate matter. Humans, too, each possess a portion of the divine logos.
The Stoics took all activity to imply a logos or spiritual principle. As the operative principle of the world, the logos was anima mundi to them, a concept which later influenced Philo of Alexandria, although he derived the contents of the term from Plato. In his Introduction to the 1964 edition of Marcus Aurelius' Meditations, the Anglican priest Maxwell Staniforth wrote that "Logos ... had long been one of the leading terms of Stoicism, chosen originally for the purpose of explaining how deity came into relation with the universe".
Public discourse on ancient Greek rhetoric has historically emphasized Aristotle's appeals to logos, pathos, and ethos, while less attention has been directed to Isocrates' teachings about philosophy and logos, and their partnership in generating an ethical, mindful polis. Isocrates does not provide a single definition of logos in his work, but Isocratean logos characteristically focuses on speech, reason, and civic discourse. He was concerned with establishing the "common good" of Athenian citizens, which he believed could be achieved through the pursuit of philosophy and the application of logos.