The human body, like all organic bodies, is a machine. Artificial automata and natural bodies are distinguished only in degree. Machines fashioned by the hand of man perform their functions by means of visible and tangible instruments, while natural bodies employ organs which, for the most part, are too minute to be perceived. As the clock-maker constructs a clock from wheels and weights so that it is able to go of itself, so God has made man's body out of dust, only, being a far superior artist, he produces a work of art which is better constructed and capable of far more wonderful movements. The cause of death is the destruction of some important part of the machine, which prevents it from running longer; a corpse is a broken clock, and the departure of the soul comes only as a result of death. The common opinion that the soul generates life in the body is erroneous. It is rather true that life must be present before the soul enters into union with the body, as it is also true that life must have ended before it dissolves the bond.
The sole principles of physiology are motion and heat. The heat (vital warmth, a fire without light), which God has put in the heart as the central organ of life, has for its function the promotion of the circulation of the blood, in the description of which Descartes mentions with praise the discoveries of Harvey (De Motu Cordis et Sanguinis in Animalibus, 1628). From the blood are separated its finest, most fiery, and most mobile parts, called by Descartes "animal spirits" (spiritus animales sive corporales), and described as a "very subtle wind" or "pure and vivid flame," which ascend into the cavities of the brain, reach the pineal gland suspended in its center (conarion, glans pinealis, glandula), pass into the nerves, and, by their action on the muscles connected with the nerves, effect the motions of the limbs. These views refer to the body alone, and so are as true of animals as of men. If automata existed similar to animals in all respects, both external and internal, it would be absolutely impossible to distinguish them from real animals. If, however, they were made to resemble human bodies, two signs would indicate their unreality—we would find no communication of ideas by means of language, and also an absence of those bodily movements which take their origin in the reason (and not merely in the constitution of the body). The only thing which raises man above the brute is his rational soul, which we are on no account to consider a product of matter, but which is an express creation of God, superadded. The union of the soul or the mind (anima sive mens) with the body is, it is true, not so loose that the mind merely dwells in the body, like a pilot in a ship, nor, on the other hand, in view of the essential contrariety of the two substances, is it so intimate as to be more than a unio compositionis. Although the soul is united to the whole body, an especially active intercourse between them is developed at a single point, the pineal gland, which is distinguished by its central, protected position, above all, by the fact that it is the only cerebral organ that is not double. This gland, together with the animal spirits passing to and from it, mediates between mind and body; and as the point of union for the twofold impressions from the (right and left) eyes and ears, without which objects would be perceived double instead of single, is the seat of the soul. Here the soul exercises a direct influence on the body and is directly affected by it; here it dwells, and at will produces a slight, peculiar movement of the gland, through this a change in the course of the animal spirits (for it is not capable of generating motion, but only of changing its direction), and, finally, movements of the members; just as, on the other hand, it remarks the slightest change in the course of the spiritus through a corresponding movement of the gland, whose motions vary according to the sensuous properties of the object to be perceived, and responds by sensations. Although Descartes thus limits the direct interaction of soul and body to a small part of the organism, he makes an exception in the case of memoria, which appears to him to be more of a physical than a psychical function, and which he conjectures to be diffused through the whole brain.
In spite of the comprehensive meaning which Descartes gives to the notion cogitatio, it is yet too narrow to leave room for an anima vegetativa and an anima sensitiva. Whoever makes mind and soul equivalent, holds that their essence consists in conscious activity alone, and interprets sensation as a mode of thought, cannot escape the paradox of denying to animals the possession of a soul. Descartes does not shrink from such a conclusion. Animals are mere machines; they are bodies animated, but soulless; they lack conscious perception and appetition, though not the appearance of them. When a clock strikes seven it knows nothing of the fact; it does not regret that it is so late nor long soon to be able to strike eight; it wills nothing, feels nothing, perceives nothing. The lot of the brute is the same. It sees and hears nothing, it does not hunger or thirst, it does not rejoice or fear, if by these anything more than mere corporeal phenomena is to be meant; of all these it possesses merely the unconscious material basis; it moves and motion goes on in it—that is all. The psychology of Descartes, which has had important results,[1] divides cogitationes into two classes: actiones and passiones. Action denotes everything which takes its origin in, and is in the power of, the soul; passion, everything which the soul receives from without, in which it can make no change, which is impressed upon it. The further development of this distinction is marred by the crossing of the most diverse lines of thought, resulting in obscurities and contradictions. Descartes's simple, naïve habits of thought and speech, which were those of a man of the world rather than of a scholar, were quite incompatible with the adoption and consistent use of a finely discriminated terminology; he is very free with sive, and not very careful with the expressions actio, passio, perceptio, affectio, volitio. First he equates activity and willing, for the will springs exclusively from the soul—it is only in willing that the latter is entirely independent; while, on the other hand, passivity is made equivalent to representation and cognition, for the soul does not create its ideas, but receives them,—sensuous impressions coming to her quite evidently from the body. These equations, "actio—the practical, passio = the theoretical function," are soon limited and modified, however. The natural appetites and affections are forms of volition, it is true, but not free products of the mind, for they take their origin in its connection with the body. Further, not all perceptions have a sensuous origin; when the soul makes free use of its ideas in imagination, especially when in pure thought it dwells on itself, when without the interference of the imagination it gazes on its rational nature, it is by no means passive merely. Every act of the will, again, is accompanied by the consciousness of volition. The volitio is an activity, the cogitatio volitionis a passivity; the soul affects itself, is passively affected through its own activity, is at the same instant both active and passive.
[Footnote 1: For details cf. the able monograph of Dr. Anton Koch, 1881.]
Thus not every volition, e.g. sensuous desire, is action nor all perception, e.g. that of the pure intellect, passion. Finally, certain psychical phenomena fall indifferently under the head of perception or of volition, e.g., pain, which is both an indistinct idea of something and an impulse to shun it. In accordance with these emendations, and omitting certain disturbing points of secondary importance, the matter may be thus represented:
COGITATIO.
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ACTIO ¦ PASSIO
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(Mens sola; clarae et distinctae ¦ (Mens unita cum corpore;
ideae.) ¦ confusae ideae.)
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VOLITIO: ¦
6. Voluntas. 3b. Commotiones ¦ 3a. Affectus. 2. Appetitus naturales.
¦ intellectuales¦ ¦ ¦
¦ ¦ \ /
¦ ¦ ————v———-
Judicium. ¦ Sensus interni
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PERCEPTIO: 4. Imaginatio
———^———
/ \
5. Intellectus 4b. Phantasia. ¦ 4a. Memoria. 1. Sensus externi.
Accordingly six grades of mental function are to be distinguished: (1) The external senses. (2) The natural appetites. (3) The passions (which, together with the natural appetites, constitute the internal senses, and from which the mental emotions produced by the intellect are quite distinct). (4) The imagination with its two divisions, passive memory and active phantasy. (5) The intellect or reason. (6) The will. These various stages or faculties are, however, not distinct parts of the soul, as in the old psychology, in opposition to which Descartes emphatically defends the unity of the soul. It is one and the same psychical power that exercises the higher and the lower, the rational and the sensuous, the practical and the theoretical activities.
Of the mental functions, whether representative images, perceptions, or volitions, a part are referred to body (to parts of our own body, often also to external objects), and produced by the body (by the animal spirits and, generally, by the nerves as well), while the rest find both object and cause in the soul. Intermediate between the two classes stand those acts of the will which are caused by the soul, but which relate to the body, e.g., when I resolve to walk or leap; and, what is more important, the passions, which relate to the soul itself, but which are called forth, sustained, and intensified by certain motions of the animal spirits. Since only those beings which consist of a body as well as a soul are capable of the passions, these are specifically human phenomena. These affections, though very numerous, may be reduced to a few simple or primary ones, of which the rest are mere specializations or combinations. Descartes enumerates six primitive passions (which number Spinoza afterward reduced one-half)—admiratio, amor et odium, cupiditas (désir), gaudium et tristitia. The first and the fourth have no opposites, the former being neither positive nor negative, and the latter both at once. Wonder, which includes under it esteem and contempt, signifies interest in an object which neither attracts us by its utility nor repels us by its hurtfulness, and yet does not leave us indifferent. It is aroused by the powerful or surprising impression made by the extraordinary, the rare, the unexpected. Love seeks to appropriate that which is profitable; hate, to ward off that which is harmful, to destroy that which is hostile. Desire or longing looks with hope or fear to the future. When that which is feared or hoped for has come to pass, joy and grief come in, which relate to existing good and evil, as desire relates to those to come.
The Cartesian theory of the passions forms the bridge over which its author passes from psychology to ethics. No soul is so weak as to be incapable of completely mastering its passions, and of so directing them that from them all there will result that joyous temper advantageous to the reason. The freedom of the will is unlimited. Although a direct influence on the passions is denied it,—it can neither annul them merely at its bidding, nor at once reduce them to silence, at least, not the more violent ones,—it still has an indirect power over them in two ways. During the continuance of the affection (e.g., fear) it is able to arrest the bodily movements to which the affection tends (flight), though not the emotion itself, and, in the intervals of quiet, it can take measures to render a new attack of the passion less dangerous. Instead of enlisting one passion against another, a plan which would mean only an appearance of freedom, but in fact a continuance in bondage, the soul should fight with its own weapons, with fixed maxims (judicia), based on certain knowledge of good and evil. The will conquers the emotions by means of principles, by clear and distinct knowledge, which sees through and corrects the false values ascribed to things by the excitement of the passions. Besides this negative requirement, "subjection of the passions," Descartes' contributions to ethics—in the letters to Princess Elizabeth on human happiness, and to Queen Christina on love and the highest good—were inconsiderable. Wisdom is the carrying out of that which has been seen to be best, virtue is steadfastness, sin inconstancy therein. The goal of human endeavor is peace of conscience, which is attained only through the determination to be virtuous, i.e., to live in harmony with self.
Besides its ethical mission, the will has allotted to it the theoretical function of affirmation and negation, i.e., of judgment. If God in his veracity and goodness has bestowed on man the power to know truth, how is misuse of this power, how is error possible? Single sensations and ideas cannot be false, but only judgments—the reference of ideas to objects. Judgment or assent is a matter of the will; so that when it makes erroneous affirmations or negations, when it prefers the false judgment to the true, it alone is guilty. Our understanding is limited, our will unlimited; the latter reaches further than the former, and can assent to a judgment even before its constituent parts have attained the requisite degree of clearness. False judgment is prejudgment, for which we can hold neither God nor our own nature responsible. The possibility of error, as well as the possibility of avoiding error, resides in the will. This has the power to postpone its assent or dissent, to hold back its decision until the ideas have become entirely clear and distinct. The supreme perfection is the libertas non errandi. Thus knowledge itself becomes a moral function; the true and the good are in the last analysis identical. The contradiction with which Descartes has been charged, that he makes volition and cognition reciprocally determinative, that he bases moral goodness on the clearness of ideas and vice versa, does not exist. We must distinguish between a theoretical and a practical stadium in the will; it is true of the latter that it depends on knowledge of the right, of the former that the knowledge of the right is dependent on it. In order to the possibility of moral action the will must conform to clear judgment; in order to the production of the latter the will must be moral. It is the unit-soul, which first, by freely avoiding overhasty judgment, cognizes the truth, to exemplify it later in moral conduct.