Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that there is nothing voluntary in irrational animals. For a thing is called "voluntary" from "voluntas" . Now since the will is in the reason (De Anima iii, 9), it cannot be in irrational animals. Therefore neither is there anything voluntary in them.

Objection 2: Further, according as human acts are voluntary, man is said to be master of his actions. But irrational animals are not masters of their actions; for "they act not; rather are they acted upon," as Damascene says (De Fide Orth. ii, 27). Therefore there is no such thing as a voluntary act in irrational animals.

Objection 3: Further, Damascene says (De Fide Orth. 24) that "voluntary acts lead to praise and blame." But neither praise nor blame is due to the acts of irrational minds. Therefore such acts are not voluntary.

On the contrary, The Philosopher says (Ethic. iii, 2) that "both children and irrational animals participate in the voluntary." The same is said by Damascene (De Fide Orth. 24) and Gregory of Nyssa .

I answer that, As stated above (Article 1), it is essential to the voluntary act that its principle be within the agent, together with some knowledge of the end. Now knowledge of the end is twofold; perfect and imperfect. Perfect knowledge of the end consists in not only apprehending the thing which is the end, but also in knowing it under the aspect of end, and the relationship of the means to that end. And such knowledge belongs to none but the rational nature. But imperfect knowledge of the end consists in mere apprehension of the end, without knowing it under the aspect of end, or the relationship of an act to the end. Such knowledge of the end is exercised by irrational animals, through their senses and their natural estimative power.

Consequently perfect knowledge of the end leads to the perfect voluntary; inasmuch as, having apprehended the end, a man can, from deliberating about the end and the means thereto, be moved, or not, to gain that end. But imperfect knowledge of the end leads to the imperfect voluntary; inasmuch as the agent apprehends the end, but does not deliberate, and is moved to the end at once. Wherefore the voluntary in its perfection belongs to none but the rational nature: whereas the imperfect voluntary is within the competency of even irrational animals.

Reply to Objection 1: The will is the name of the rational appetite; and consequently it cannot be in things devoid of reason. But the word "voluntary" is derived from "voluntas" , and can be extended to those things in which there is some participation of will, by way of likeness thereto. It is thus that voluntary action is attributed to irrational animals, in so far as they are moved to an end, through some kind of knowledge.

Reply to Objection 2: The fact that man is master of his actions, is due to his being able to deliberate about them: for since the deliberating reason is indifferently disposed to opposite things, the will can be inclined to either. But it is not thus that voluntariness is in irrational animals, as stated above.

Reply to Objection 3: Praise and blame are the result of the voluntary act, wherein is the perfect voluntary; such as is not to be found in irrational animals.

Articulus 2

Argumentum 1

Ad secundum sic proceditur. Videtur quod voluntarium non sit in brutis animalibus. Voluntarium enim a voluntate dicitur.

Voluntas autem, cum sit in ratione, ut dicitur in III de anima, non potest esse in brutis animalibus. Ergo neque voluntarium in eis invenitur.

Argumentum 2

Praeterea, secundum hoc quod actus humani sunt voluntarii, homo dicitur esse dominus suorum actuum. Sed bruta animalia non habent dominium sui actus, non enim agunt, sed magis aguntur, ut Damascenus dicit.

Ergo in brutis animalibus non est voluntarium.

Argumentum 3

Praeterea, Damascenus dicit quod actus voluntarios sequitur laus et vituperium.

Sed actibus brutorum animalium non debetur neque laus neque vituperium. Ergo in eis non est voluntarium.

Sed Contra

Sed contra est quod dicit philosophus, in III ethic., quod pueri et bruta animalia communicant voluntario.

Et idem dicunt Damascenus et Gregorius Nyssenus.

Corpus

Respondeo dicendum quod, sicut dictum est, ad rationem voluntarii requiritur quod principium actus sit intra, cum aliqua cognitione finis. Est autem duplex cognitio finis, perfecta scilicet, et imperfecta. Perfecta quidem finis cognitio est quando non solum apprehenditur res quae est finis sed etiam cognoscitur ratio finis, et proportio eius quod ordinatur in finem ad ipsum. Et talis cognitio finis competit soli rationali naturae. Imperfecta autem cognitio finis est quae in sola finis apprehensione consistit, sine hoc quod cognoscatur ratio finis, et proportio actus ad finem. Et talis cognitio finis invenitur in brutis animalibus, per sensum et aestimationem naturalem. Perfectam igitur cognitionem finis sequitur voluntarium secundum rationem perfectam, prout scilicet, apprehenso fine, aliquis potest, deliberans de fine et de his quae sunt ad finem, moveri in finem vel non moveri. Imperfectam autem cognitionem finis sequitur voluntarium secundum rationem imperfectam, prout scilicet apprehendens finem non deliberat, sed subito movetur in ipsum. Unde soli rationali naturae competit voluntarium secundum rationem perfectam, sed secundum rationem imperfectam, competit etiam brutis animalibus.

Ad 1

Ad primum ergo dicendum quod voluntas nominat rationalem appetitum, et ideo non potest esse in his quae ratione carent.

Voluntarium autem denominative dicitur a voluntate, et potest trahi ad ea in quibus est aliqua participatio voluntatis, secundum aliquam convenientiam ad voluntatem. Et hoc modo voluntarium attribuitur animalibus brutis, inquantum scilicet per cognitionem aliquam moventur in finem.

Ad 2

Ad secundum dicendum quod ex hoc contingit quod homo est dominus sui actus, quod habet deliberationem de suis actibus, ex hoc enim quod ratio deliberans se habet ad opposita, voluntas in utrumque potest. Sed secundum hoc voluntarium non est in brutis animalibus, ut dictum est.

Ad 3

Ad tertium dicendum quod laus et vituperium consequuntur actum voluntarium secundum perfectam voluntarii rationem; qualis non invenitur in brutis.