The end is not altogether extrinsic to the act
The end is not altogether extrinsic to the act, because it is related to the act as principle or terminus; and thus it is just this that is essential to an act.
Reply to Objection 1. The end is not altogether extrinsic to the act, because it is related to the act as principle or terminus; and thus it is just this that is essential to an act, viz. to proceed from something, considered as action, and to proceed towards something, considered as passion.