Procheiron (from χείρ, "hand") literally means "what is at hand" — an instrument always ready for use. In Stoic practice the πρόχειρα are short teachings, compressed to formulae, which the philosopher keeps in consciousness at every moment, in order to apply them without delay or deliberation. Not an extensive theory committed to memory for the sake of knowledge, but battle-gear: a few key theses worked up into automatic readiness, so that at the moment of a passion or a trial they trigger like a prepared response. Hadot's metaphor: the teachings are like a surgeon's instruments, which must be on his person — not sought out at the moment of the operation.

(1) Single out a narrow set of central theses of one's school — five to seven formulae, no more; (2) phrase them briefly, so they fit on one line and arrive whole rather than being reconstructed in parts; (3) repeat them regularly (morning / evening meditation, on waking, before action) — not for understanding but for interiorisation into the "muscle memory" of judgment; (4) apply them to particular impressions (φαντασίαι) as they appear — not to "recall" the teaching but to pass the impression through the teaching. Marcus's Meditations itself functions in part as such a notebook of πρόχειρα.