Place in the book. A compressed, almost logical passage: on the self-sufficiency of reason and on what a "right action" is. The discipline of action.

The self-sufficiency of reason. TERMReason (ὁ λόγος) and "the rational art" (ἡ λογικὴ τέχνη) are DOGMApowers sufficient to themselves (ἑαυταῖς ἀρκούμεναι): they need nothing from outside — neither for their being nor for their works. This is the Stoic αὐτάρκεια of the rational faculty: reason carries its measure within itself.

From principle to end. They "set out" (TERMὁρμῶνται) from their own principle (οἰκεία ἀρχή) and "travel" (ὁδεύουσι) to TERMthe end set before them (προκείμενον τέλος). Reason is self-moving and self-directed: both the road and the goal are its own. The same image of the straight road to the προκείμενον is in 08-60 (the mind goes κατ’ εὐθύ to its object even while circling and taking precautions — straight in intention, not in trajectory).

Right action as the straight road. Hence "right actions" (κατορθώσεις — from κατορθόω, "to set straight, to succeed") are so named because they signify the ὀρθότης (straightness) of the ὁδός (road). The metaphor of the road: to act rightly is to go straight. κατόρθωσις is the sage's perfect action, beside the καθῆκον (the appropriate action of one still on the way).

Discipline and parallels. The principal discipline is action (κατόρθωσις, right action). The background is the Stoic distinction of καθῆκον / κατόρθωμα (DL VII; LS 59); the self-sufficiency of reason — cf. DOGMAthe self-sufficiency of virtue.