Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that a habit cannot be corrupted. For habit is within its subject like a second nature; wherefore it is pleasant to act from habit. Now so long as a thing is, its nature is not corrupted. Therefore neither can a habit be corrupted so long as its subject remains.

Objection 2: Further, whenever a form is corrupted, this is due either to corruption of its subject, or to its contrary: thus sickness ceases through corruption of the animal, or through the advent of health. Now science, which is a habit, cannot be lost through corruption of its subject: since "the intellect," which is its subject, "is a substance that is incorruptible" (De Anima i, text. 65). In like manner, neither can it be lost through the action of its contrary: since intelligible species are not contrary to one another (Metaph. vii, text. 52). Therefore the habit of science can nowise be lost.

Objection 3: Further, all corruption results from some movement. But the habit of science, which is in the soul, cannot be corrupted by a direct movement of the soul itself, since the soul is not moved directly. It is, however, moved indirectly through the movement of the body: and yet no bodily change seems capable of corrupting the intelligible species residing in the intellect: since the intellect independently of the body is the proper abode of the species; for which reason it is held that habits are not lost either through old age or through death. Therefore science cannot be corrupted. For the same reason neither can habits of virtue be corrupted, since they also are in the rational soul, and, as the Philosopher declares (Ethic. i, 10), "virtue is more lasting than learning."

On the contrary, The Philosopher says (De Long. et Brev. Vitae ii) that "forgetfulness and deception are the corruption of science." Moreover, by sinning a man loses a habit of virtue: and again, virtues are engendered and corrupted by contrary acts (Ethic. ii, 2).

I answer that, A form is said to be corrupted directly by its contrary; indirectly, through its subject being corrupted. When therefore a habit has a corruptible subject, and a cause that has a contrary, it can be corrupted both ways. This is clearly the case with bodily habits---for instance, health and sickness. But those habits that have an incorruptible subject, cannot be corrupted indirectly. There are, however, some habits which, while residing chiefly in an incorruptible subject, reside nevertheless secondarily in a corruptible subject; such is the habit of science which is chiefly indeed in the "possible" intellect, but secondarily in the sensitive powers of apprehension, as stated above (Question 50, Article 3, ad 3). Consequently the habit of science cannot be corrupted indirectly, on the part of the "possible" intellect, but only on the part of the lower sensitive powers.

We must therefore inquire whether habits of this kind can be corrupted directly. If then there be a habit having a contrary, either on the part of itself or on the part of its cause, it can be corrupted directly: but if it has no contrary, it cannot be corrupted directly. Now it is evident that an intelligible species residing in the "possible" intellect, has no contrary; nor can the active intellect, which is the cause of that species, have a contrary. Wherefore if in the "possible" intellect there be a habit caused immediately by the active intellect, such a habit is incorruptible both directly and indirectly. Such are the habits of the first principles, both speculative and practical, which cannot be corrupted by any forgetfulness or deception whatever: even as the Philosopher says about prudence (Ethic. vi, 5) that "it cannot be lost by being forgotten." There is, however, in the "possible" intellect a habit caused by the reason, to wit, the habit of conclusions, which is called science, to the cause of which something may be contrary in two ways. First, on the part of those very propositions which are the starting point of the reason: for the assertion "Good is not good" is contrary to the assertion "Good is good" (Peri Herm. ii). Secondly, on the part of the process of reasoning; forasmuch as a sophistical syllogism is contrary to a dialectic or demonstrative syllogism. Wherefore it is clear that a false reason can corrupt the habit of a true opinion or even of science. Hence the Philosopher, as stated above, says that "deception is the corruption of science." As to virtues, some of them are intellectual, residing in reason itself, as stated in Ethic. vi, 1: and to these applies what we have said of science and opinion. Some, however, viz. the moral virtues, are in the appetitive part of the soul; and the same may be said of the contrary vices. Now the habits of the appetitive part are caused therein because it is natural to it to be moved by the reason. Therefore a habit either of virtue or of vice, may be corrupted by a judgment of reason, whenever its motion is contrary to such vice or virtue, whether through ignorance, passion or deliberate choice.

Reply to Objection 1: As stated in Ethic. vii, 10, a habit is like a second nature, and yet it falls short of it. And so it is that while the nature of a thing cannot in any way be taken away from a thing, a habit is removed, though with difficulty.

Reply to Objection 2: Although there is no contrary to intelligible species, yet there can be a contrary to assertions and to the process of reason, as stated above.

Reply to Objection 3: Science is not taken away by movement of the body, if we consider the root itself of the habit, but only as it may prove an obstacle to the act of science; in so far as the intellect, in its act, has need of the sensitive powers, which are impeded by corporal transmutation. But the intellectual movement of the reason can corrupt the habit of science, even as regards the very root of the habit. In like manner a habit of virtue can be corrupted. Nevertheless when it is said that "virtue is more lasting than learning," this must be understood in respect, not of the subject or cause, but of the act: because the use of virtue continues through the whole of life, whereas the use of learning does not.

Articulus 1

Argumentum 1

Ad primum sic proceditur. Videtur quod habitus corrumpi non possit. Habitus enim inest sicut natura quaedam, unde operationes secundum habitum sunt delectabiles. Sed natura non corrumpitur, manente eo cuius est natura.

Ergo neque habitus corrumpi potest, manente subiecto.

Argumentum 2

Praeterea, omnis corruptio formae vel est per corruptionem subiecti, vel est a contrario, sicut aegritudo corrumpitur corrupto animali, vel etiam superveniente sanitate.

Sed scientia, quae est quidam habitus, non potest corrumpi per corruptionem subiecti, quia intellectus, qui est subiectum eius, est substantia quaedam, et non corrumpitur, ut dicitur in I de anima.

Similiter etiam non potest corrumpi a contrario, nam species intelligibiles non sunt ad invicem contrariae, ut dicitur in VII metaphys..

Ergo habitus scientiae nullo modo corrumpi potest.

Argumentum 3

Praeterea, omnis corruptio est per aliquem motum.

Sed habitus scientiae, qui est in anima, non potest corrumpi per motum per se ipsius animae, quia anima per se non movetur.

Movetur autem per accidens per motum corporis. Nulla autem transmutatio corporalis videtur posse corrumpere species intelligibiles existentes in intellectu, cum intellectus sit per se locus specierum, sine corpore, unde ponitur quod nec per senium nec per mortem corrumpuntur habitus. Ergo scientia corrumpi non potest. Et per consequens, nec habitus virtutis, qui etiam est in anima rationali, et, sicut philosophus dicit in I ethic., virtutes sunt permanentiores disciplinis.

Sed Contra

Sed contra est quod philosophus dicit, in libro de longitudine et brevitate vitae, quod scientiae corruptio est oblivio et deceptio.

Peccando etiam aliquis habitum virtutis amittit. Et ex contrariis actibus virtutes generantur et corrumpuntur, ut dicitur II ethic..

Corpus

Respondeo dicendum quod secundum se dicitur aliqua forma corrumpi per contrarium suum, per accidens autem, per corruptionem sui subiecti. Si igitur fuerit aliquis habitus cuius subiectum est corruptibile, et cuius causa habet contrarium, utroque modo corrumpi poterit, sicut patet de habitibus corporalibus, scilicet sanitate et aegritudine.

Illi vero habitus quorum subiectum est incorruptibile, non possunt corrumpi per accidens. Sunt tamen habitus quidam qui, etsi principaliter sint in subiecto incorruptibili, secundario tamen sunt in subiecto corruptibili, sicut habitus scientiae, qui principaliter est quidem in intellectu possibili, secundario autem in viribus apprehensivis sensitivis, ut supra dictum est.

Et ideo ex parte intellectus possibilis, habitus scientiae non potest corrumpi per accidens; sed solum ex parte inferiorum virium sensitivarum.

Est igitur considerandum si possunt huiusmodi habitus per se corrumpi. Si igitur fuerit aliquis habitus qui habeat aliquod contrarium, vel ex parte sua vel ex parte suae causae, poterit per se corrumpi, si vero non habet contrarium, non poterit per se corrumpi. Manifestum est autem quod species intelligibilis in intellectu possibili existens, non habet aliquid contrarium. Neque iterum intellectui agenti, qui est causa eius, potest aliquid esse contrarium.

Unde si aliquis habitus sit in intellectu possibili immediate ab intellectu agente causatus, talis habitus est incorruptibilis et per se et per accidens. Huiusmodi autem sunt habitus primorum principiorum, tam speculabilium quam practicorum, qui nulla oblivione vel deceptione corrumpi possunt, sicut philosophus dicit, in VI ethic., de prudentia, quod non perditur per oblivionem.

Aliquis vero habitus est in intellectu possibili ex ratione causatus, scilicet habitus conclusionum, qui dicitur scientia, cuius causae dupliciter potest aliquid contrarium esse. Uno modo, ex parte ipsarum propositionum ex quibus ratio procedit, etenim enuntiationi quae est, bonum est bonum, contraria est ea quae est, bonum non est bonum, secundum philosophum, in II periherm..

Alio modo, quantum ad ipsum processum rationis; prout syllogismus sophisticus opponitur syllogismo dialectico vel demonstrativo. Sic igitur patet quod per falsam rationem potest corrumpi habitus verae opinionis, aut etiam scientiae.

Unde philosophus dicit quod deceptio est corruptio scientiae, sicut supra dictum est.

Virtutum vero quaedam sunt intellectuales, quae sunt in ipsa ratione, ut dicitur in VI ethic., de quibus est eadem ratio quae est de scientia vel opinione. Quaedam vero sunt in parte animae appetitiva, quae sunt virtutes morales, et eadem ratio est de vitiis oppositis. Habitus autem appetitivae partis causantur per hoc quod ratio nata est appetitivam partem movere.

Unde per iudicium rationis in contrarium moventis quocumque modo, scilicet sive ex ignorantia, sive ex passione, vel etiam ex electione, corrumpitur habitus virtutis vel vitii.

Ad 1

Ad primum ergo dicendum quod, sicut dicitur in VII ethic., habitus similitudinem habet naturae, deficit tamen ab ipsa.

Et ideo, cum natura rei nullo modo removeatur ab ipsa, habitus difficile removetur.

Ad 2

Ad secundum dicendum quod, etsi speciebus intelligibilibus non sit aliquid contrarium, enuntiationibus tamen et processui rationis potest aliquid esse contrarium, ut dictum est.

Ad 3

Ad tertium dicendum quod scientia non removetur per motum corporalem quantum ad ipsam radicem habitus, sed solum quantum ad impedimentum actus; inquantum intellectus indiget in suo actu viribus sensitivis, quibus impedimentum affertur per corporalem transmutationem. Sed per intelligibilem motum rationis potest corrumpi habitus scientiae, etiam quantum ad ipsam radicem habitus. Et similiter etiam potest corrumpi habitus virtutis.

Tamen quod dicitur, virtutes esse permanentiores disciplinis, intelligendum est non ex parte subiecti vel causae, sed ex parte actus, nam virtutum usus est continuus per totam vitam, non autem usus disciplinarum.