Thomas Aquinas, "Summa Theologica"
The “Summa Theologica” of St. Thomas Aquinas, Part II (Second Part), Second Number (QQ. XLVII-LXXIX), translated by Fathers of the English Dominican Province, Volume 10, Benziger Brothers, 1918
Thomas Aquinas, Summa Theologica, Second Part of the Second Part, Question 49, Article 1, Reply to Objection 2
pp. 34-35:
Reply to Objection 2. Just as aptitude for prudence is in our nature, while its perfection comes through practice or grace, so too, as Tully says in his Rhetoric [Ad Herenn. de Arte Rhet. iii, 16,24], memory not only arises from nature, but is also aided by art and diligence.
There are four things whereby a man perfects his memory. First, when a man wishes to remember a thing, he should take some suitable yet somewhat unwonted illustration of it, since the unwonted strikes us more, and so makes a greater and stronger impression on the mind; the mind; and this explains why we remember better what we saw when we were children. Now the reason for the necessity of finding these illustrations or images, is that simple and spiritual impressions easily slip from the mind, unless they be tied as it were to some corporeal image, because human knowledge has a greater hold on sensible objects. For this reason memory is assigned to the sensitive part of the soul. Secondly, whatever a man wishes to retain in his memory he must carefully consider and set in order, so that he may pass easily from one memory to another. Hence the Philosopher says (De Memor. et Remin. ii): “Sometimes a place brings memories back to us: the reason being that we pass quickly from the one to the other.” Thirdly, we must be anxious and earnest about the things we wish to remember, because the more a thing is impressed on the mind, the less it is liable to slip out of it. Wherefore Tully says in his Rhetoric [Ad Herenn. de Arte Rhet. iii.] that “anxiety preserves the figures of images entire.” Fourthly, we should often reflect on the things we wish to remember. Hence the Philosopher says (De Memoria i) that “reflection preserves memories,” because as he remarks (De Memoria ii) “custom is a second nature”: wherefore when we reflect on a thing frequently, we quickly call it to mind, through passing from one thing to another by a kind of natural order.1 2
ST II-II, Q. 49, Art. 1, ad. 2:3
Ad secundum dicendum quod sicut prudentia aptitudinem quidem habet ex natura, sed eius complementum est ex exercitio vel gratia ita etiam, ut Tullius dicit, in sua rhetorica, memoria non solum a natura proficiscitur, sed etiam habet plurimum artis et industriae.
Et sunt quatuor per quae homo proficit in bene memorando. Quorum primum est ut eorum quae vult memorari quasdam similitudines assumat convenientes, nec tamen omnino consuetas, quia ea quae sunt inconsueta magis miramur, et sic in eis animus magis et vehementius detinetur; ex quo fit quod eorum quae in pueritia vidimus magis memoremur. Ideo autem necessaria est huiusmodi similitudinum vel imaginum adinventio, quia intentiones simplices et spirituales facilius ex anima elabuntur nisi quibusdam similitudinibus corporalibus quasi alligentur, quia humana cognitio potentior est circa sensibilia. Unde et memorativa ponitur in parte sensitiva. Secundo, oportet ut homo ea quae memoriter vult tenere sua consideratione ordinate disponat, ut ex uno memorato facile ad aliud procedatur. Unde philosophus dicit, in libro de Mem., a locis videntur reminisci aliquando, causa autem est quia velociter ab alio in aliud veniunt. Tertio, oportet ut homo sollicitudinem apponat et affectum adhibeat ad ea quae vult memorari, quia quo aliquid magis fuerit impressum animo, eo minus elabitur. Unde et Tullius dicit, in sua rhetorica, quod sollicitudo conservat integras simulacrorum figuras. Quarto, oportet quod ea frequenter meditemur quae volumus memorari. Unde philosophus dicit, in libro de Mem., quod meditationes memoriam salvant, quia, ut in eodem libro dicitur, consuetudo est quasi natura; unde quae multoties intelligimus cito reminiscimur, quasi naturali quodam ordine ab uno ad aliud procedentes.