The Logos

Logos =logic=non-contradictory thought?

Short answer: roughly—originally, yes, but it's more nuanced.

Explanation (concise):

- In classical Greek philosophy, "logos" (λόγος) covered several related meanings: speech, reason, account, principle, and order. Among those, it did include rational, non-contradictory discourse—thinking or speech that gives an account and makes sense.

- Heraclitus used logos as the underlying rational principle or law governing change; for him it was the intelligible order of the world.

- In Stoicism, logos = rational structure of the cosmos (a universal reason), and human reason is a spark of that logos; rational, coherent thought was aligned with living according to logos.

- Plato and Aristotle treat logos as reasoning or argument—Aristotle especially formalized logical coherence and non-contradiction as central to rational discourse.

- In later Christian theology (e.g., Gospel of John), Logos is theological (the divine Word), expanding the term beyond mere logical consistency.

So logos often implies rational, coherent, non-contradictory thought or principle, but its meaning varies by author and context and can also mean speech, account, or cosmic principle rather than only "non-contradictory thought."