Source, in full
Ethics. Book 1 - 1C4; cited in: Peter W. G. Morris, Jeffrey K. Pinto, Jonas Söderlund (2011) The Oxford Handbook of Project Management. In modern language Aristotle here wrote that "Defining the question is half the answer".
More quotes by Aristotle
But he who neither thinks for himself, nor lays to heart another's wisdom, this is a useless man.’
The best friend is he that, when he wishes a person's good, wishes it for that person's own sake.
Attribution
Quote text and notes from Wikiquote: Aristotle (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.