Philostorgia literally means "affection by στοργή," that is, the particular form of love that binds parents and children, kin, people of one blood. In the Greek vocabulary of emotion, στοργή is distinct from ἔρως (erotic love), from φιλία (friendship-esteem), and from ἀγάπη (universal good-will): it is a warm, unchosen, naturally-biological attachment. The Stoics carry this biological term over into ethics: the virtuous person feels philostorgia toward all human beings as toward TERMkin — not because they are pleasing or useful, but because they are part of the same rational whole. This is not sentimentalism but a structural consequence of DOGMAoikeiōsis.

Aristot. Eth. Nic. VIII (general places on στοργή as kin-love; the precise para- and section to be verified); Plut. De amore prolis (the natural attachment of parents to offspring); Chrysippus on στοργή in the context of oikeiōsis (cf. SVF, vol. III). In Marcus the φιλοστοργ-/στοργ- root is lexically attested in: Med. 1.9 (φιλοστοργότατον of Sextus); 1.17 (φιλόστοργον of Faustina the wife); 2.5 (φιλοστόργως in the list of dispositions in which to approach an action); 6.30 (the received text contains φιλόστοργος ἀκόρως in the portrait of Antoninus — the proper lexical centre of the whole series). In Med. 1.16 the root στοργ- is not present in the received text: the famous formula "φιλόστοργος, but not to satiety," applied to Antoninus, belongs to 6.30, not to 1.16; cf. also 11.18 (a thematic background; the lexical attestation to be checked).

In 02-05 philostorgia is one of four virtues in which every action is to be undertaken (alongside σεμνότης — dignity, ἐλευθερία — freedom, δικαιότης — justice). Its inclusion here is characteristic of Marcus: it has no formal place in the classical Stoic list of virtues (φρόνησις, ἀνδρεία, σωφροσύνη, δικαιοσύνη), but Marcus systematically adds it as the tone in which virtuous action is to be carried out. Not "perform your duty," but "perform your duty φιλοστόργως" — with warmth. The lexical centre of the series is Med. 6.30 (φιλόστοργος ἀκόρως in the portrait of Antoninus); there Antoninus is the practical embodiment of this note. In 01-16 (the first portrait of Antoninus) the root στοργ- is not lexically used, although the thematic affinity is plain. Linked to DOGMAoikeiosis (the structural foundation) and TERMsynergia (the active expression).