I. In rhet.
1. An exercise of the reasoning powers, calm reasoning, ratiocination (opp. impulsio, a passionate feeling, impulse; cf. “argumentatio): ratiocinatio est diligens et considerata faciendi aliquid aut non faciendi excogitatio,” Cic. Inv. 2, 5, 18: “etiam sapientiae studiosos maxime medicos esse, si ratiocinatio hoc faceret,” Cels. 1, praef. § 49.—
2. A certain form of reasoning, a syllogism: “ratiocinatio est oratio ex ipsā re probabile aliquid eliciens, quod expositum et per se cognitum, suā se vi et ratione confirmet,” Cic. Inv. 1, 34, 57; cf.: “si ex alio colligitur aliud, nec improprium nec inusitatum nomen est ratiocinationis,” Quint. 8, 4, 16; Cic. Inv. 2, 50, 152; Quint. 5, 10, 6; 3, 6, 15; 5, 14, 5 al.—
3. A rhet. figure, reasoning in an interrogative form: “ratiocinatio est, per quam ipsi a nobis rationem poscimus, quare quidque dicamus, etc.,” Auct. Her. 4, 16, 23.—
II. In archit., theory (opp.: “fabrica, practice): ratiocinatio est, quae res fabricatas solertiā ac ratione proportionis demonstrare atque explicare potest,” Vitr. 1, 1, 1; 15.
