Phantasia is the basic unit of Stoic psychology: an "impression in the ruling part," what presents itself to consciousness prior to any judgment upon it. Chrysippus defined φαντασία as τύπωσιν ἐν ψυχῇ — "an imprint upon the soul" (qualified: not a literal wax-tablet impression, but a pneumatic alteration). The Stoics divided φαντασίαι into (a) cognitive (καταληπτικαί) — those that carry the evidence of their own truth, and to which the sage alone gives assent, and (b) non-cognitive — all the rest, which must be approached with suspension of judgment (epochē). The φαντασία in itself is ethically neutral; ethical significance arises only when the TERMruling part gives or withholds assent (συγκατάθεσις) to it.

SVF I 53, 61–62 (Zeno); II 53–60 (Chrysippus); II 70–80, 87, 99 (the doctrine of καταληπτικὴ φαντασία); DL VII 45–54; LS 39, 40. In Marcus: Med. 2.5; 3.16; 05-02 (how easy to push away every troubling impression and be at peace); 05-16; 05-22 (the canon applied to the φαντασία of harm); 06-13 (the bare definitions — the impression that reaches the things themselves); 06-16 (τὸ τυποῦσθαι κατὰ φαντασίαν — a lower grade, not valuable in itself); 06-36 (μὴ φαντάζου — do not imagine evil alien to the source you revere); 07-02 (dogmas live only while their φαντασίαι are unquenched — they must be rekindled); 07-17 (ὦ φαντασία — "go away as you came; I am not angry, only go"); 07-29 (Ἐξάλειψον τὴν φαντασίαν — "wipe out the impression," the first of the seven commands); 07-47 (the φαντασίαι of contemplating stars and elements purge the grime of the life below); 07-54 (τῇ παρούσῃ φαντασίᾳ ἐμφιλοτεχνεῖν — the third member of the triad: let no ἀκατάληπτον slip in); 08-07 (assent to no φαντασία false or unclear — the first of the three conditions); 08-13 (to every φαντασία — physics, ethics, dialectic); 08-26 (διάκρισις τῶν πιθανῶν φαντασιῶν — discernment of plausible impressions); 08-36 (do not let "the impression of the whole life" — ἡ τοῦ ὅλου βίου φαντασία — confuse you); 08-49 (the famous "add nothing of yourself to what the φαντασία announces"); 08-51 (μὴ ἐν ταῖς φαντασίαις ἀλᾶσθαι — not to wander in impressions); 09-07 (ἐξαλεῖψαι φαντασίαν — "blot out the impression": the first command of the triad-by-negation); 11.19; 05-36 (do not be swept away wholesale by the φαντασία).

In 02-05 φαντασίαι are mentioned as the background from which one must "secure oneself a leisure" (σχολὴν … πορίζειν) — that is, not allow them to scatter attention away from the task at hand. Stoic attention is, first and foremost, work on φαντασίαι: separating the impression from the judgment one attaches to it. The famous Med. 8.49 — "add nothing of yourself to what the impression says" — is the condensed formula of epochē. Φαντασία binds together all three disciplines: assent (the κρίσις passed on an impression), desire (what seems good or bad to me), and action (impulse is born from assent). See TERMpathos — passion as false assent to an evaluative impression.