Full Idea
Each of us stops inquiring about what way to act when he brings back the starting-point to himself and, within himself, to the leading element, since this is what deliberately chooses.
Gist of Idea
Deliberation ends when we return to our leading element, which does the choosing
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1113a04)
A Reaction
[Thomson 'dominant part'; Ross' ruling part'; Irwin 'guiding part'] Sounds awfully like the 'element' which we now call 'the will'. It probably actually refers to the reason, but this is the aspect of reason which controls action (rather than belief).
Book Reference
Aristotle: 'Nicomachean Ethics', ed/tr. Reeve, C.D.C. [Hackett 2024], p.41