Sect. 133The Animal Side of Man’s NatureThe Animal Side of Man’s Nature

I. Although the soul which animates the human body differs essentially from the principle which gives life to the lower animals, and although the soul, by means of its spiritual functions, exercises control over the body and its life: still, the animal and vegetative life of the body of man is subject to physical laws. Man and animal have in common not only the abstract concept of “animal life,” but also its concrete mode of existence, its status and conditions. The imperfections which Holy Scripture sums up under the name of “infirmity of the flesh” have their origin in the animal part of man. The spiritual soul informs the body in the same manner as the vital principle informs the bodies of mere animals, viz. in such a way as to endow the body with a life in keeping with its nature. The soul does not spiritualize the body, or give it the impassibility and incorruptibility proper to spirits; it does not even absolutely control all the bodily motions and tendencies. By the mere fact of creation, then, and not on account of any subsequent derangement, the animal life of man is naturally subject to the imperfections of animal life in general.

Holy Scripture offers a foundation for this doctrine when it teaches that the body, taken from the earth, was, through the inbreathing of a spiritual soul, made into “a living soul”—that is, received the life proper to its own earthly nature. This is the argument of St. Paul (1 Cor. 15:44 sqq.), who further deduces from the earthly origin of man his infirmities and corruptibility.

II. The general principle just laid down contains the following special propositions:—

1. The constitution of the human body subjects it to the laws and conditions of existence and development which rule the life of plants and animals, viz. the laws of nutrition, growth, and reproduction. The first characteristic, then, which distinguishes the animal body from the pure spirit is this very necessity of taking something from without for its sustenance, a necessity which appears most clearly in the functions of respiration

2. The fact that life is dependent on a continual supply of external nourishment, shows that increase, decrease, and extinction are natural to it. The tree of life, provided by God for our first parents, bore indeed a food which would have prevented the extinction of life. But to partake of the fruit of life would only have averted the natural necessity of decay and death. Left to its natural resources, the immortal soul of man would not have been able to secure immortality for the body. Again, the words of the Divine curse, “Dust thou art, and unto dust thou shalt return,” point clearly to the fact that death was due to the Fall only inasmuch as man, by reason of his sin, was left to his natural corruptibility. The possibility and necessity of death are, therefore, natural attributes, flowing from the very constitution of human nature. By a positive Divine disposition they were suspended until the first sin was committed.

3. The spiritual essence of the soul in like manner cannot prevent the internal and external disturbances of the vital functions which lead to pain and suffering. The possibility of suffering was certainly the same in our first parents as in us; God alone, by supernatural intervention, was able to prevent this possibility from passing into actuality.

4. Vegetative life in plants and animals is subject to a passibility which, in the former, appears as corruption of their substance, in the latter as pain and suffering. On a level with these phenomena the Fathers place that possibility which is peculiar to the sensitive life of man and animals. It consists in the sensitive faculties being affected in anticipation or even in spite of reason. Such motions are rightly called “passions,” because they result from an impulse received on the ground of some subjective want, and are more or less dependent on the excitability of the bodily organism. Of course, a positive force is required for action at the reception of the objective impulse; the imperfection of the sensitive faculty lies both in the inability to act without such impulse, and in the necessity to act in accordance with it. This passive excitability of the appetitive faculties of animal life is described by St. Augustine as a weakness and idleness of nature, or as a morbid quality of nature.

Catholic doctrine and sound philosophy alike demand that the appetitive faculties of sensitive life in man should occupy an inferior position. Reason should rule over passion as far as possible by controlling inordinate desires, and by refusing the use of the body for wrong purposes. This refusal is always in the power of rational will, for the power of man over the external motions of his body is despotic, whereas his power over his desires is only politic, or, as we now say, constitutional. Although the motions of concupiscence are due to the infirmity of human nature, the soul cannot get rid of this infirmity, because the influence of the soul, as form of the body, is like the influence of non-spiritual forms; the life it gives is animal life with all its concomitant perfections and imperfections.

5. It is thus evident that, by the very constitution of his nature, man is liable to spontaneous motions in his sensitive tendencies, over which the will has, at best, but little control. In other words, concupiscence is an attribute of human nature. In animals which have no reason, concupiscence is the mainspring of activity; it is in harmony with their whole nature, whereas in man it is a disturbing element in the higher life of the soul. The subjection to concupiscence in man belongs to the same order as the possibility and necessity of death and of physical pain, viz. to passibility and corruptibility in animal life.

6. The nature of the animal body asserts itself most in the manifestations of the sexual instinct. These are the most impetuous; they are accompanied by spontaneous motions of the flesh, and are the least controllable by reason. This peculiarity is accounted for on the ground that the functions of vegetative life, to which the sexual instinct belongs, are carried out independently of the will. Another and better ground is, that the object of this instinct is the preservation, rather than the multiplication, of the race, so that by satisfying it the mortal individual secures to itself the only immortality it can attain, viz. a continued existence in individuals of its own kind. Inasmuch, then, as the human body shared with other earthly beings the faculty of propagation as well as the necessity of death, it was but natural that it should also share with them the morbid excitability of the most natural of instincts. Again, no other domain of life brings out better the contrast between the spiritual and the animal faculties of the soul. The “law of death” in the manifestations of the sexual instinct is so strong that in their presence the soul loses command over the motions, and almost over the very use, of the body. The imperfection and lowness of its animal life is thus strongly brought home to the soul, and the contrast with its nobler spiritual life may account for the sense of shame inseparable from sexual excitement.

III. Thus all the imperfections and defects to be found in the animal part of man are not the result of the destruction and perversion of man’s original state, but the necessary natural result of the constitution of human nature. The objections raised against the Catholic doctrine are based upon misconception or misrepresentation. To answer them in detail would lead to a needless repetition of the propositions contained in this chapter.