Soli rationali naturae competit voluntarium secundum rationem perfectam, sed secundum rationem imperfectam, competit etiam brutis animalibus, quia imperfectam cognitionem finis sequitur voluntarium secundum rationem imperfectam, prout scilicet apprehendens finem non deliberat, sed subito movetur in ipsum.
The voluntary in its perfection belongs to none but the rational nature, whereas the imperfect voluntary is within the competency of even irrational animals because 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.
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.
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" [will], 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.
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.
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.
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.
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.