1 Objection 1: It would seem that children would have had perfect use of reason at birth. For that children have not perfect use of reason in our present state, is due to the soul being weighed down by the body; which was not the case in paradise, because, as it is written, The corruptible body is a load upon the soul Wis. 9, 15). Therefore, before sin and the corruption which resulted therefrom, children would have had the perfect use of reason at birth.
1 Ad secundum sic proceditur. Videtur quod pueri in statu innocentiae mox nati habuissent perfectum usum rationis. Nunc enim pueri perfectum usum rationis non habent propter hoc, quod anima per corpus aggravatur. Hoc autem tunc non erat, quia, ut dicitur Sap. IX, corpus quod corrumpitur, aggravat animam. Ergo ante peccatum et corruptionem a peccato subsecutam, pueri mox nati perfectum usum rationis habuissent.
2 Objection 2: Further, some animals at birth have the use of their natural powers, as the lamb at once flees from the wolf. Much more, therefore, would men in the state of innocence have had perfect use of reason at birth.
2 Praeterea, quaedam alia animalia mox nata habent naturalis industriae usum, sicut agnus statim fugit lupum. Multo ergo magis homines in statu innocentiae mox nati habuissent usum perfectum rationis.
3 On the contrary, In all things produced by generation nature proceeds from the imperfect to the perfect. Therefore children would not have had the perfect use of reason from the very outset.
3 Sed contra est quod natura procedit ab imperfecto ad perfectum in omnibus generatis. Ergo pueri non statim a principio habuissent perfectum usum rationis.
4 I answer that, As above stated Question 84, Article 7), the use of reason depends in a certain manner on the use of the sensitive powers; wherefore, while the senses are tired and the interior sensitive powers hampered, man has not the perfect use of reason, as we see in those who are asleep or delirious. Now the sensitive powers are situate in corporeal organs; and therefore, so long as the latter are hindered, the action of the former is of necessity hindered also; and likewise, consequently, the use of reason. Now children are hindered in the use of these powers on account of the humidity of the brain; wherefore they have perfect use neither of these powers nor of reason. Therefore, in the state of innocence, children would not have had the perfect use of reason, which they would have enjoyed later on in life. Yet they would have had a more perfect use than they have now, as to matters regarding that particular state, as explained above regarding the use of their limbs Question 99, Article 1).
4 Respondeo dicendum quod, sicut ex supra dictis patet, usus rationis dependet quodammodo ex usu virium sensitivarum, unde ligato sensu, et impeditis interioribus viribus sensitivis, homo perfectum usum rationis non habet, ut patet in dormientibus et phreneticis. Vires autem sensitivae sunt virtutes quaedam corporalium organorum, et ideo, impeditis earum organis, necesse est quod earum actus impediantur, et per consequens rationis usus. In pueris autem est impedimentum harum virium, propter nimiam humiditatem cerebri. Et ideo in eis non est perfectus usus rationis, sicut nec aliorum membrorum. Et ideo pueri in statu innocentiae non habuissent perfectum usum rationis, sicut habituri erant in perfecta aetate. Habuissent tamen perfectiorem quam nunc, quantum ad ea quae ad eos pertinebant quantum ad statum illum; sicut et de usu membrorum superius est dictum.
5 Reply to Objection 1: The corruptible body is a load upon the soul, because it hinders the use of reason even in those matters which belong to man at all ages.
5 Ad primum ergo dicendum quod aggravatio additur ex corruptione corporis in hoc, quod usus rationis impeditur quantum ad ea etiam quae pertinent ad hominem secundum quamcumque aetatem.
6 Reply to Objection 2: Even other animals have not at birth such a perfect use of their natural powers as they have later on. This is clear from the fact that birds teach their young to fly; and the like may be observed in other animals. Moreover a special impediment exists in man from the humidity of the brain, as we have said above Question 99, Article 1).
6 Ad secundum dicendum quod etiam alia animalia non habent ita perfectum usum industriae naturalis statim a principio, sicut postea. Quod ex hoc patet, quod aves docent volare pullos suos, et similia in aliis generibus animalium inveniuntur. Et tamen in homine est speciale impedimentum propter abundantiam humiditatis cerebri, ut supra dictum est.