200. Thesis XII. The soul of man is essentially a simple being.
Proof. Our soul takes in simple ideas; for instance, those of truth, holiness, justice, infinity, being, etc.; but a principle that can take in or conceive a simple idea is simple. For if it were composed of parts, then either, 1, Each part would take in the whole idea; each part would be a soul, and every man would be not I but we, which is against the testimony of consciousness and of common sense; or, 2, Each part would take in a part of a simple idea; but a simple idea is not an aggregate of parts; or, 3, Only one part would take in the whole idea, the other parts not apprehending it; then the part apprehending the simple idea would be the soul. If this part is simple, the soul is simple, as we maintain it is. But if that part is itself compound, the same reasoning must again be applied to it; and the absurdities arising cannot be avoided except by granting that the principle which conceives simple ideas is simple, or that the soul is simple.
201. Objections: 1. A simple soul is unthinkable, i.e., cannot be thought of, says Huxley. Answer. It is unimaginable, not unthinkable; if we could not think of it, we could not point out the essential notes by which it is distinguished from all other beings.
2. Our intellect is affected by our bodily ailments; it may be disorganized, deranged, enfeebled, excited, etc.; therefore it consists of parts. Answer. The intellect itself cannot be deranged, but its co-natural objects are presented to it by the phantasms of our imagination. Now, our imagination can be deranged, for it is an organic power; and in reality all mental derangement, enfeeblement, excitement, etc., can be traced to affections of the imagination.
3. Phrenology shows that all action of the soul is modified according to the modifications of the brain; therefore the soul is identified with the brain. Answer. Phrenology is not founded upon certain principles; therefore it is not a science and cannot draw scientific conclusions. Elevations in the brain do not always correspond to elevations in the cranium, nor do mental dispositions always correspond to special modifications of the brain. Even if they did, it would only prove that the action of the soul is modified when its organ is affected; for the brain is the organ of the imagination;. and the imagination exerts an extrinsic influence on the understanding, presenting to it the images that assist thought.
202. Thesis XIII. The soul of man is spiritual.
Explanation. Spirituality expresses more than simplicity; every spirit is simple, but a thing may be simple without being spiritual; such is the soul of the brute. (See No. 145.) A being is spiritual when it can act and exist without material organs.
Proof 1. The soul will actually survive the body, as will be proved further on (Nos. 213, 214); this supposes that it can exist and act without the body; therefore, that it is spiritual.
Proof 2. The soul, even now, performs acts in which matter cannot have an intrinsic share; for instance, when we conceive such ideas as virtue, holy, honest, will, intellect, God, angel, spirit, etc.; also when we love spiritual good, which cannot affect any organism. In fact, all abstract, all universal ideas are beyond the reach of matter; for matter being essentially concrete and singular cannot represent any but concrete and singular objects. Likewise all judgments, reasonings, volitions, every act that is distinctively intellectual, is inorganic in its essence; the imagination does furnish it with materials extrinsically, but cannot enter into its specific action. Now, it is evident that a being acts according to its nature; therefore the nature of the intellect is spiritual, distinct from matter, independent of matter in its own specific sphere of activity; therefore intrinsically capable of acting and existing without a body. The argument may be stated thus: An organic faculty -- i.e., a faculty which has matter as a con-cause of its operations -- can only perceive such objects as can make a material impression upon it; but our intellect perceives objects which cannot make a material impression upon it; therefore our intellect is not an organic but a spiritual faculty. But a faculty is necessarily proportioned to the subject in which it resides ; therefore the soul is spiritual.
Proof 3. No being can tend to a good which is above its nature; but the soul tends to spiritual goods, essentially above all material natures; therefore its nature is spiritual.
Proof 4. Matter cannot act freely, as materialists grant; but our soul acts freely, as proved above (No. 198); therefore our soul is not matter.
Proof 5. Our soul is conscious of its own acts; but consciousness supposes inorganic action and inorganic lieing. For an organ cannot inspect itself, a being dependent intrinsically on matter cannot double itself back on its own acts; therefore the acts of consciousness and the nature of a conscious soul are spiritual.
203. Objections: 1. All intellectual action begins in sense, therefore the soul is dependent on the body for all its acts. Answer. The soul is, in our present state of existence, extrinsically dependent on the body in more than one way viz.: for its communication with the visible world, for its phantasms, and for the exercise of its faculties generally; but since matter does not intrinsically co-operate in its intellectual acts, there is nothing impossible in the separate existence and action of the soul, without the extrinsic aid of the body.
2. The soul is the form of the body; therefore its very being is the being of the body. Answer. Though it makes one being with the body, still its being is not exhausted by the being of the body; in other words, it is the form of the body, but it is not only the form of the body; it is more.
3. Whether the aid of organs in the acts of the intellect be called intrinsic or extrinsic, it is necessary for intellectual action; therefore the soul cannot act without the body. Answer. The aid of phantasms is now necessary, because every being acts dependently on the circumstances in which it is placed; thus, when we are in a room, we depend on the window to see objects outside. The soul, therefore, being at present one being with its body, must now act in union with that body, using the aid of that body as far as it can aid the act of intelligence. Therefore we now think of all things in connection with phantasms. When, however, the body will be no more one with the soul, the latter can retain all its intellectual species formerly acquired; it can know its own essence directly, and, by reasoning on all this, know its Creator; besides, it can receive divinely infused knowledge, and knowledge communicated to it by other intelligences in manners suitable to its new condition.
204. Thesis XIV. The intellectual soul is the only principle of life in man, and is therefore the form of the human body.
Explanation. It was proved above (Thesis V.) that the vital principle of any living body is truly the form of that body; if, then, we prove here that the intellectual soul is the only vital principle in man, we thereby establish the fact that the soul is the form of the body. Now, the intellectual soul is really the only vital principle in man.
Proof 1. Every man is conscious of being a unit, which he signifies by the term 'I'; he is conscious, moreover, that the same 'I' feels, and thinks, and wills. Now, if there were more than one vital principle in man, the intellectual soul could not be conscious of all this; for vital principles perform immanent actions, and one principle cannot be conscious to itself of performing the immanent act of another principle, conscious of doing what it does not do.
Proof 2. The more the intellect works, the more the inferior vitality of a man is relaxed; on the other hand, when the lower functions of life are most energetically exercised, the mind is less fit for its own activity. Thus, while wrapped in deep thought, a man scarcely sees or hears; he digests imperfectly. Now, all this cannot be explained except by supposing that the same principle performs the higher and the lower functions of human life.
Proof 3. Anatomy shows that the entire organism of the human body is one unit, combining the organs of vegetable and animal action into one harmonious whole.
205. Corollaries. 1, The soul is in every part of the body, acting in every organ with a vitality appropriate to such organ; seeing in the eye, hearing in the ear, breathing in the lungs, digesting in the stomach, moving in the muscles, etc.
2. All organic action in man is the action of the compound soul and body; for matter can do nothing except in virtue of its form.
3. The soul is directly united with the prime matter or potential principle, being itself the active principle: it gives to the body all its powers and its very nature of a body, and such a body. Still, when the soul departs at death, the body cannot cease to be a body of some kind; for the potential principle of matter cannot exist without a form. Whether this new form be one form for the whole corpse, a form supplied for the purpose by the laws of nature, or whether the flesh, bone, sinew, etc., have each its own form, existing before death under the control of the life principle and now acting independently, matters very little. (Pesch, Inst. Phil. Nat., No. 210.)
206. Those who do not understand the Peripatetic system of matter and form are greatly embarrassed to explain how body and soul act on each other. Various theories have been imagined, all of them unscientific. Plato supposed that the soul is seated in the brain, whence it rules the body as the rider does his horse. The assistance theory of Descartes maintains that soul and body do not act on each other, but God acts on either one of them whenever a modification occurs in the other. Leibnitz's theory of pre-established harmony teaches that God, foreseeing all that any soul would do in the course of life, has in his wisdom given to each soul a body so constructed that it will automatically act just when and as the soul wills, though the soul does not influence it in the least. The theory of physical influence makes the soul and the body act on each other as two distinct beings. Günther imagined a principle of animal life, called by him psyche, which he supposed to be substantially united with the intellectual soul. No system can be scientific which makes man to be, not one but two beings, each having its own activity; the only theory in harmony with man's essential unity is that which views the soul as the form of the body. The form is not acted upon by the body, nor does it act on the body; but it is itself the active principle of the body. Thus, the soul is not acted upon by the eye or the ear, but the living eye, the living ear acts, perceiving color and sound. The whole question about the interaction of body and soul thus ceases to be a question at all; for there can be no interaction where there are not two agents each having its own action, but the action is common to both.