1 Objection 1: It seems that to live belongs to all natural things. For the Philosopher says Phys. viii, 1) that Movement is like a kind of life possessed by all things existing in nature. But all natural things participate in movement. Therefore all natural things partake of life.
1 Ad primum sic proceditur. Videtur quod omnium rerum naturalium sit vivere. Dicit enim philosophus, in VIII Physic., quod motus est ut vita quaedam natura existentibus omnibus. Sed omnes res naturales participant motum. Ergo omnes res naturales participant vitam.
2 Objection 2: Further, plants are said to live, inasmuch as they in themselves a principle of movement of growth and decay. But local movement is naturally more perfect than, and prior to, movement of growth and decay, as the Philosopher shows Phys. viii, 56, 57). Since then, all natural bodies have in themselves some principle of local movement, it seems that all natural bodies live.
2 Praeterea, plantae dicuntur vivere, inquantum habent in seipsis principium motus augmenti et decrementi. Sed motus localis est perfectior et prior secundum naturam quam motus augmenti et decrementi, ut probatur in VIII Physic. Cum igitur omnia corpora naturalia habeant aliquod principium motus localis, videtur quod omnia corpora naturalia vivant.
3 Objection 3: Further, amongst natural bodies the elements are the less perfect. Yet life is attributed to them, for we speak of living waters. Much more, therefore, have other natural bodies life.
3 Praeterea, inter corpora naturalia imperfectiora sunt elementa. Sed eis attribuitur vita, dicuntur enim aquae vivae. Ergo multo magis alia corpora naturalia vitam habent.
4 On the contrary, Dionysius says Div. Nom. vi, 1) that The last echo of life is heard in the plants, whereby it is inferred that their life is life in its lowest degree. But inanimate bodies are inferior to plants. Therefore they have not life.
4 Sed contra est quod dicit Dionysius, VI cap. de Div. Nom., quod plantae secundum ultimam resonantiam vitae habent vivere, ex quo potest accipi quod ultimum gradum vitae obtinent plantae. Sed corpora inanimata sunt infra plantas. Ergo eorum non est vivere.
5 I answer that, We can gather to what things life belongs, and to what it does not, from such things as manifestly possess life. Now life manifestly belongs to animals, for it said in De Vegetab. i that in animals life is manifest. We must, therefore, distinguish living from lifeless things, by comparing them to that by reason of which animals are said to live: and this it is in which life is manifested first and remains last. We say then that an animal begins to live when it begins to move of itself: and as long as such movement appears in it, so long as it is considered to be alive. When it no longer has any movement of itself, but is only moved by another power, then its life is said to fail, and the animal to be dead. Whereby it is clear that those things are properly called living that move themselves by some kind of movement, whether it be movement properly so called, as the act of an imperfect being, that is, of a thing in potentiality, is called movement; or movement in a more general sense, as when said of the act of a perfect thing, as understanding and feeling are called movement. Accordingly all things are said to be alive that determine themselves to movement or operation of any kind: whereas those things that cannot by their nature do so, cannot be called living, unless by a similitude.
5 Respondeo dicendum quod ex his quae manifeste vivunt, accipere possumus quorum sit vivere, et quorum non sit vivere. Vivere autem manifeste animalibus convenit, dicitur enim in libro de vegetabilibus, quod vita in animalibus manifesta est. Unde secundum illud oportet distinguere viventia a non viventibus secundum quod animalia dicuntur vivere. Hoc autem est in quo primo manifestatur vita, et in quo ultimo remanet. Primo autem dicimus animal vivere, quando incipit ex se motum habere; et tandiu iudicatur animal vivere, quandiu talis motus in eo apparet; quando vero iam ex se non habet aliquem motum, sed movetur tantum ab alio tunc dicitur animal mortuum, per defectum vitae. Ex quo patet quod illa proprie sunt viventia, quae seipsa secundum aliquam speciem motus movent; sive accipiatur motus proprie, sicut motus dicitur actus imperfecti, idest existentis in potentia; sive motus accipiatur communiter, prout motus dicitur actus perfecti, prout intelligere et sentire dicitur moveri, ut dicitur in III de anima. Ut sic viventia dicantur quaecumque se agunt ad motum vel operationem aliquam, ea vero in quorum natura non est ut se agant ad aliquem motum vel operationem, viventia dici non possunt, nisi per aliquam similitudinem.
6 Reply to Objection 1: These words of the Philosopher may be understood either of the first movement, namely, that of the celestial bodies, or of the movement in its general sense. In either way is movement called the life, as it were, of natural bodies, speaking by a similitude, and not attributing it to them as their property. The movement of the heavens is in the universe of corporeal natures as the movement of the heart, whereby life is preserved, is in animals. Similarly also every natural movement in respect to natural things has a certain similitude to the operations of life. Hence, if the whole corporeal universe were one animal, so that its movement came from an intrinsic moving force, as some in fact have held, in that case movement would really be the life of all natural bodies.
6 Ad primum ergo dicendum quod verbum illud philosophi potest intelligi vel de motu primo, scilicet corporum caelestium; vel de motu communiter. Et utroque modo motus dicitur quasi vita corporum naturalium, per similitudinem; et non per proprietatem. Nam motus caeli est in universo corporalium naturarum, sicut motus cordis in animali, quo conservatur vita. Similiter etiam quicumque motus naturalis hoc modo se habet ad res naturales, ut quaedam similitudo vitalis operationis. Unde, si totum universum corporale esset unum animal, ita quod iste motus esset a movente intrinseco, ut quidam posuerunt, sequeretur quod motus esset vita omnium naturalium corporum.
7 Reply to Objection 2: To bodies, whether heavy or light, movement does not belong, except in so far as they are displaced from their natural conditions, and are out of their proper place; for when they are in the place that is proper and natural to them, then they are at rest. Plants and other living things move with vital movement, in accordance with the disposition of their nature, but not by approaching thereto, or by receding from it, for in so far as they recede from such movement, so far do they recede from their natural disposition. Heavy and light bodies are moved by an extrinsic force, either generating them and giving them form, or removing obstacles from their way. They do not therefore move themselves, as do living bodies.
7 Ad secundum dicendum quod corporibus gravibus et levibus non competit moveri, nisi secundum quod sunt extra dispositionem suae naturae, utpote cum sunt extra locum proprium, cum enim sunt in loco proprio et naturali, quiescunt. Sed plantae et aliae res viventes moventur motu vitali, secundum hoc quod sunt in sua dispositione naturali, non autem in accedendo ad eam vel in recedendo ab ea, imo secundum quod recedunt a tali motu, recedunt a naturali dispositione. Et praeterea, corpora gravia et levia moventur a motore extrinseco, vel generante, qui dat formam, vel removente prohibens, ut dicitur in VIII Physic., et ita non movent seipsa, sicut corpora viventia.
8 Reply to Objection 3: Waters are called living that have a continuous current: for standing waters, that are not connected with a continually flowing source, are called dead, as in cisterns and ponds. This is merely a similitude, inasmuch as the movement they are seen to possess makes them look as if they were alive. Yet this is not life in them in its real sense, since this movement of theirs is not from themselves but from the cause that generates them. The same is the case with the movement of other heavy and light bodies.
8 Ad tertium dicendum quod aquae vivae dicuntur, quae habent continuum fluxum, aquae enim stantes, quae non continuantur ad principium continue fluens, dicuntur mortuae, ut aquae cisternarum et lacunarum. Et hoc dicitur per similitudinem, inquantum enim videntur se movere, habent similitudinem vitae. Sed tamen non est in eis vera ratio vitae, quia hunc motum non habent a seipsis, sed a causa generante eas; sicut accidit circa motum aliorum gravium et levium.