Full Idea
That part of the soul is deliberative which is capable of discerning a cause: the reason for the sake of which - which is one of the causes - 'cause' being something because-of-which.
Gist of Idea
The deliberative part of the soul discerns explanatory causes
Source
Aristotle (Eudemian Ethics [c.333 BCE], 1226b26)
Book Reference
Aristotle: 'Eudemian Ethics I,II and VIII', ed/tr. Woods,Michael [OUP 1992], p.31
A Reaction
I take because-of-which to be the correct explanation. Since my model of practical reasoning is partly forensic detection, this seems right. Sherlock Holmes spots causes.