Two trajectories. A short comparison with a precise difference. The arrow (βέλος) flies on a single trajectory — straight, but blind and irreversible: once loosed, it cannot turn. The TERMmind (νοῦς) moves "otherwise" (ἄλλως): it can be cautious (εὐλαβεῖσθαι) and "turn about in inquiry" (περὶ τὴν σκέψιν στρέφεσθαι) — circle, weigh, draw back and approach from another side. And yet — here is the point — it moves "none the less" (οὐδὲν ἧττον) κατ’ εὐθύ, straight, to what is set before it (τὸ προκείμενον).

Circling is not wandering. The mind's roundabout moves are no deviation from the goal: circumspection and all-sided examination are precisely its way of going straight. The arrow is straight mechanically; the mind is straight despite the crookedness of its path — straight in the intention, not the trajectory. Marcus has just applied the same κατ’ εὐθύ to the sunbeam (8.57: the ray "is extended in a right line" (κατ’ εὐθύ), braces against the obstacle and stands): in both, straightness is the mark of the unswerving movement of the rational toward its own. The same thesis is unfolded in 5.14 (reason and philosophy "make their way to the end which is proposed to them," τὸ προκείμενον τέλος, and such acts are called κατορθώσεις, "which word signifies that they proceed by the right road," ὀρθότης τῆς ὁδοῦ). The governing discipline is action: to hold the bearing on the προκείμενον through all one's circumspection.