βάπτεται ἡ TERMψυχή ὑπὸ τῶν TERMφαντασιῶν — the soul is "dyed" by its impressions, as cloth or wool takes the colour of a dye. The verb βάπτω means "to dip, to plunge into dye, to dye"; hence the sense: the character of the mind (διάνοια) is not given once and for all but is the accumulated colour of what the soul habitually imagines. "Such as your frequent impressions, such will your mind be."

The metaphor is exact in that dyeing is a process of dipping and soaking: the colour is set not by a single thought but by repetition, habit, a continuous series (συνέχεια). Hence the practical imperative: "dye it" (βάπτε) deliberately — choose what you dip the mind in. A fast colour is an interiorised teaching that has become one's optics.

Med. 05-16 — the image in pure form: "such as your habitual thoughts, such your mind; for the soul is dyed by the thoughts." Kin to the practice of "soaking" the mind in right teachings (prokheiron). The Greek background: Plato, Resp. IV 429d–430b — the image of dyers making the colour of wool fast (indelible), as an analogy for the education by which convictions become "colourfast." Cf. 06-30: "μὴ βαφῇς" — the same βάπτω figure, but of the character dyed by power/the purple: do not let the office "dye" you (do not be "Caesarified").

In 05-16 the image grounds the discipline of assent: since the mind takes the colour of its TERMimpressions, one must deliberately "dye" it with right ones, by the practice of repetition. It differs from the clearing of the sky: there the mind returns to a natural clarity (the clouds are accretions); here the mind is actively coloured, and the only question is with what colour. Linked to DOGMAthe identity of the "I" with the ruling part: the character of the mind just is the person.