Full Idea
For Aristotle logos is the ability to speak rationally about, with the hope of attaining knowledge, questions of value.
Clarification
'Logos' is the broad Greek concept of human reasoning
Gist of Idea
For Aristotle logos is essentially the ability to talk rationally about questions of value
Source
comment on Aristotle (works [c.330 BCE]) by David Roochnik - The Tragedy of Reason p.26
Book Reference
Roochnik,David: 'The Tragedy of Reason: the Platonic logos' [Routledge 1990], p.26