Disputationes metaphysicae

1. The common way of speaking in this matter is that the accidental form is the proximate principle, and the substantial form the principal principle, of all the actions of the supposit, even of the accidental ones. But in what this notion of principal principle consists, or what its influx is, the Doctors either do not declare, or, if they say anything in passing, they intimate that it consists only in this, that the form is the root and principle of the accidental faculty, which was given to it by nature so as to be its proximate principle for eliciting action. In the very exercise of accidental action, however, the substantial form is not believed to have a proximate and actual influx. And the reason can be given both from that principle that created substance cannot be the proximate principle of an accident, and also because for effecting an accident another accident is a sufficient principle.

2. For vital functions not the accident alone, but the substance also, inflows proximately.—Nevertheless I think a distinction must be used; for among these actions some are vital, others not. Of the former it seems it must be said that not the accidental faculty alone, but also the soul itself through its substance, inflows proximately into them in its own order. Experience seems to persuade this conclusion; for these vital actions take place in so intimate a manner that they seem to proceed actually from the very first principle of life, which is the soul; whence it comes about that, although the eye has the image present and receives the species from it, if the soul does not attend, it does not see. Nor does it matter if someone says that this comes from the distraction of the imagination or the common sense, both because I shall make the same argument about the common sense and the imagination. But if it be said that then the sensible species does not pass beyond the external sense, we shall take from that an argument against the former evasion. For if the species of a present sensible object, changing the external sense, does not reach the internal sense when the soul does not attend, this is because the species of the exterior sense is not communicated to the interior sense except by means of the act of the exterior sense. From which it follows that the exterior sense senses prior in nature to the interior's cooperation; for this cooperation seems to follow upon the operation of the exterior sense; therefore the reason why, in the aforesaid case, the exterior sense does not sense does not come from the interior sense, but rather the interior sense is not touched by the species of that object because the exterior sense does not perceive it. Another cause, therefore, must be sought why the exterior sense then does not effect its act, which seems to be none other than that the soul then does not inflow into it or cooperate with it. You will say that the reason is that it does not cooperate, not indeed through its substance, but through the animal spirits, which are necessary for sense and motion. But although it is true that these spirits are necessary, yet this very thing confirms the argument and the experience adduced. For for these vital acts there is required not only the proximate faculty, but also the concurrence of the spirits, which do not flow there by chance, but by the power of some faculty supplying those spirits for that act; therefore there must be some common principle actually using those two faculties, and from natural inclination or sympathy ordering the action of the one to the act of the other.

3. Moreover, another experience confirms this, by which we proved above that there is in man only one soul, namely, because from excessive attention to the work of one faculty it is impeded in the work of another; as, if a man looks at something very attentively, he will not hear one speaking; and lest this be attributed to a defect of the spirits, the attention of the intellect too impedes the operation of sense, and the higher and more perfect it is, the more it also diminishes the motion or representation of the phantasy, and (what is more) also impedes or suspends the works of the nutritive part. But if each faculty had its operation by itself alone, there would be no reason why the operation of one should impede the operation of another; for when powers are multiplied, if one does not depend on another, nor both on one third whose power, while it is applied to both, is diminished in each, there is no reason why their operations could not be multiplied and exercised together equally perfectly. Moreover, an excellent argument is taken from the contrary, from the connection of operations; for while the intellect understands, the will is aroused to love, etc.; but this is because the same soul actually operates through both powers; for a merely habitual rooting, as it were, or remote emanation from the same soul would not suffice for this actual causality or motion and arousing, if each operation proceeded actually from its own power alone without connection in some common principle. And thence also arises the dependence between the appetite of life and cognition, so that nothing can be loved unless it is foreknown. The a priori reason, however, can be taken from the proper mode of vital operation, which requires this intimate connection with its principal formal principle so that it may take place in a manner consonant with its nature, and that its principle or supposit may effect it in a vital mode; for, so far as we can reach by experience, in this consists actual life and the primary difference of living things from non-living ones. And it is confirmed, for on this account all think that sight separated cannot see or elicit vision, nor the intellect understand. Against this opinion, however, some things can be objected, which I prudently omit, because they either are not difficult or necessarily touch on many things which belong to the science of the soul. As for what someone may ask, namely, for what the accidental and vital faculties are necessary if this form also actually inflows, he has a sufficient answer from what was said in the preceding section. For the form is as it were a universal principle, while the power is necessary as a particular, and more accommodated and proper, one, as was declared more at length there. We shall also at once dissolve other lighter objections.

4. A non-vital accident is not necessarily made proximately by the substance.—Of accidental actions, however, which are not vital, it must be said that they can be produced by accidents alone. This is evident in heat, which, existing in water and in any other subject, heats without the form of fire. Similarly whiteness, in order to effect its intentional species, does not need a superior concurrence. Likewise, hence it arises that if a thing has two active qualities, it can exercise the action of both together just as well as of one only; as water at once cools and moistens as much as it can, etc. Finally, the reason for doubting proposed above proves this, because, if the perfection of the effect is considered, the power and perfection of a like or more eminent accidental form suffices to communicate it; but from the mode of action that so intrinsic a dependence is not required, and therefore there is no reason why it should be necessary. Hence, by the way, that reason is solved inasmuch as it can be made against the former assertion. For although it can be doubted whether an operation of life is more perfect in its entity than the faculty from which it proceeds, now, however, supposing that the power is more perfect, we say that on account of the special mode of such an operation the actual immediate influx of the principal principle is necessary. Nor is it repugnant that the substantial form should inflow into the action in this way, if it has an accidental principle by which it is proximately determined to that action; for the accidental form is not always called the proximate principle because it alone inflows immediately, but because it is the principle determining the substantial form to such an action. Just as the particular cause is called proximate with respect to the first, not because the first does not inflow immediately, but because the particular cause is, in its genus, the one determining the action.

5. The substance concurs immediately to the production of no non-vital accident.—Whether organization is a vital action.—But someone will ask concerning the latter part: granted that the influx of the form is not necessary for these actions, whether it is possible and useful; that is, whether heat existing in fire is helped by the form in heating, and consequently whether, other things being equal, it heats more vehemently than when existing in another subject. Against the former part too it can be objected that sometimes a vital action seems to be exercised by some power separated from the soul, as in seed. To the former part I answer that no sufficient sign of that influx is found, and therefore it is not to be asserted lightly and without foundation. Which the mystery of the Eucharist also confirms, where the accidents of wine act equally without the influx of their form. I see that it can be said that God supplies that efficiency on account of faith in the mystery; yet where no necessity compels, there is no need to have recourse to divine causality. To the latter part: it is probable that the seed, as to the spirit planted in it, lives with vegetative life, to which pertains that vital mode which seems to be in the generation of a living thing¹; and so Aristotle seems to think of seed, II De Gener. Anim., c. 1, because it has the power of organizing the body and of generating, which seems the work of the vegetative soul. Nor does St. Thomas seem to dissent from that opinion, I, q. 118, a. 1, ad 1. Secondly, whatever be the case about this, it is answered that the actions of the vegetative soul, as to their substance, are of the same notion as those which are produced by an extrinsic principle; for all are either local motions, or alterations, or the eduction of a substantial form; hence they have the notion of vital action only from a peculiar relation to the soul as to a principle conjoined in the same self-moving supposit. Just as the speech of a man is a vital action, but the speech of an angel in an assumed body is not vital, although they are alike in exterior species. Thus, then, the action of the seed, as it is from it, is not vital, but a merely natural action; that, however, it observes the mode of life in its artistry (so to speak), or in its manner of acting, is to be referred to another, superior principle, as was touched upon above.