1 Objection 1: It would seem that the tree of life could not be the cause of immortality. For nothing can act beyond its own species; as an effect does not exceed its cause. But the tree of life was corruptible, otherwise it could not be taken as food; since food is changed into the substance of the thing nourished. Therefore the tree of life could not give incorruptibility or immortality.
1 Ad quartum sic proceditur. Videtur quod lignum vitae non poterat esse causa immortalitatis. Nihil enim potest agere ultra suam speciem, effectus enim non excedit causam. Sed lignum vitae erat corruptibile, alioquin non potuisset in nutrimentum assumi, quia alimentum convertitur in substantiam nutriti, ut dictum est. Ergo lignum vitae incorruptibilitatem seu immortalitatem conferre non poterat.
2 Objection 2: Further, effects caused by the forces of plants and other natural agencies are natural. If therefore the tree of life caused immortality, this would have been natural immortality.
2 Praeterea, effectus qui causantur a virtutibus plantarum et aliarum naturalium rerum, sunt naturales. Si ergo lignum vitae immortalitatem causasset, fuisset illa immortalitas naturalis.
3 Objection 3: Further, this would seem to be reduced to the ancient fable, that the gods, by eating a certain food, became immortal; which the Philosopher ridicules Metaph. iii, Did. ii, 4).
3 Praeterea, hoc videtur redire in fabulas antiquorum, qui dixerunt quod dii qui comedebant de quodam cibo, facti sunt immortales, quos irridet philosophus in III Metaphys.
4 On the contrary, It is written Gn. 3, 22): Lest perhaps he put forth his hand, and take of the tree of life, and eat, and live for ever. Further, Augustine says Questions. Vet. et Nov. Test. qu. 19): A taste of the tree of life warded off corruption of the body; and even after sin man would have remained immortal, had he been allowed to eat of the tree of life.
4 Sed contra est quod dicitur Gen. III, ne forte mittat manum suam et sumat de ligno vitae, et comedat et vivat in aeternum. Praeterea, Augustinus in libro de quaest. Vet. et Nov. Test., dicit, gustus arboris vitae corruptionem corporis inhibebat, denique etiam post peccatum potuit insolubilis manere, si permissum esset illi edere de arbore vitae.
5 I answer that, The tree of life in a certain degree was the cause of immortality, but not absolutely. To understand this, we must observe that in the primitive state man possessed, for the preservation of life, two remedies, against two defects. One of these defects was the lost of humidity by the action of natural heat, which acts as the soul's instrument: as a remedy against such loss man was provided with food, taken from the other trees of paradise, as now we are provided with the food, which we take for the same purpose.
The second defect, as the Philosopher says De Gener. i, 5), arises from the fact that the humor which is caused from extraneous sources, being added to the humor already existing, lessens the specific active power: as water added to wine takes at first the taste of wine, then, as more water is added, the strength of the wine is diminished, till the wine becomes watery. In like manner, we may observe that at first the active force of the species is so strong that it is able to transform so much of the food as is required to replace the lost tissue, as well as what suffices for growth; later on, however, the assimilated food does not suffice for growth, but only replaces what is lost.
Last of all, in old age, it does not suffice even for this purpose; whereupon the body declines, and finally dies from natural causes. Against this defect man was provided with a remedy in the tree of life; for its effect was to strengthen the force of the species against the weakness resulting from the admixture of extraneous nutriment. Wherefore Augustine says De Civ. Dei xiv, 26): Man had food to appease his hunger, drink to slake his thirst; and the tree of life to banish the breaking up of old age; and Questions.
Vet. et Nov. Test. qu. 19) The tree of life, like a drug, warded off all bodily corruption. Yet it did not absolutely cause immortality; for neither was the soul's intrinsic power of preserving the body due to the tree of life, nor was it of such efficiency as to give the body a disposition to immortality, whereby it might become indissoluble; which is clear from the fact that every bodily power is finite; so the power of the tree of life could not go so far as to give the body the prerogative of living for an infinite time, but only for a definite time.
For it is manifest that the greater a force is, the more durable is its effect; therefore, since the power of the tree of life was finite, man's life was to be preserved for a definite time by partaking of it once; and when that time had elapsed, man was to be either transferred to a spiritual life, or had need to eat once more of the tree of life. From this the replies to the objections clearly appear. For the first proves that the tree of life did not absolutely cause immortality; while the others show that it caused incorruption by warding off corruption, according to the explanation above given.
5 Respondeo dicendum quod lignum vitae quodammodo immortalitatem causabat, non autem simpliciter. Ad cuius evidentiam, considerandum est quod duo remedia ad conservationem vitae habebat homo in primo statu, contra duos defectus. Primus enim defectus est deperditio humidi per actionem caloris naturalis, qui est animae instrumentum. Et contra hunc defectum subveniebatur homini per esum aliorum lignorum Paradisi, sicut et nunc subvenitur nobis, per cibos quos sumimus. Secundus autem defectus est quia, ut philosophus dicit I de Generat., illud quod generatur ex aliquo extraneo, adiunctum ei quod prius erat humido praeexistenti, imminuit virtutem activam speciei, sicut aqua adiuncta vino, primo quidem convertitur in saporem vini, sed secundum quod magis et magis additur, diminuit vini fortitudinem, et tandem vinum fit aquosum.
Sic igitur videmus quod in principio virtus activa speciei est adeo fortis, quod potest convertere de alimento non solum quod sufficit ad restaurationem deperditi, sed etiam quod sufficit ad augmentum. Postmodum vero quod aggeneratur non sufficit ad augmentum, sed solum ad restaurationem deperditi. Tandem vero, in statu senectutis, nec ad hoc sufficit, unde sequitur decrementum, et finaliter naturalis dissolutio corporis. Et contra hunc defectum subveniebatur homini per lignum vitae, habebat enim virtutem fortificandi virtutem speciei contra debilitatem provenientem ex admixtione extranei.
Unde Augustinus dicit, in XIV de Civ. Dei, quod cibus aderat homini ne esuriret, potus ne sitiret, et lignum vitae ne senectus eum dissolveret. Et in libro de quaest. Vet. et Nov. Test., dicit quod vitae arbor medicinae modo corruptionem hominum prohibebat. Non tamen simpliciter immortalitatem causabat. Quia neque virtus quae inerat animae ad conservandum corpus, causabatur ex ligno vitae, neque etiam poterat immortalitatis dispositionem corpori praestare, ut nunquam dissolvi posset. Quod ex hoc patet, quia virtus cuiuscumque corporis est finita.
Unde non poterat virtus ligni vitae ad hoc se extendere ut daret corpori virtutem Durandi tempore infinito, sed usque ad determinatum tempus. Manifestum est enim quod, quanto aliqua virtus est maior, tanto imprimit durabiliorem effectum. Unde cum virtus ligni vitae esset finita, semel sumptum praeservabat a corruptione usque ad determinatum tempus; quo finito, vel homo translatus fuisset ad spiritualem vitam, vel indiguisset iterum sumere de ligno vitae. Et per hoc patet responsio ab obiecta. Nam primae rationes concludunt quod non causabat incorruptibilitatem simpliciter. Aliae vero concludunt quod causabat incorruptibilitatem impediendo corruptionem, secundum modum praedictum.