Full Idea
The Stoics think that we are exclusively moved by reason, because the soul in a narrow sense is nothing but reason.
Gist of Idea
The Stoics think that soul in the narrow sense is nothing but reason
Source
report of Stoic school (fragments/reports [c.200 BCE]) by Michael Frede - Intro to 'Rationality in Greek Thought' p.8
Book Reference
'Rationality in Greek Thought', ed/tr. Frede,M /Striker,G [OUP 1999], p.8
A Reaction
Presumably that means that desires and perceptions are not part of the 'narrow' soul. This is the culmination of Socratic intellectualism.