A tendency, an inclination, or direction. As it is used by modern writers, the word appetite has a psychological meaning. It denotes "an organic need represented in consciousness by certain sensations . . . The appetites generally recognized are those of hunger, thirst, and sex; yet the need of air, the need of exercise, and the need of sleep come under the definition." The term appetence or appetency applies not only to organic needs, but also in a general manner to "conations which find satisfaction in some positive state or result"; to "conative tendencies of all sorts ". (Baldwin, Dictionary of Philosophy and Psychology, s. v. Appetite, Appetence.) For the schoolmen, appetitus had a far more general signification, which we shall briefly explain. (References are to St. Thomas's works.) Appetite includes all forms of internal inclination (Summa Theol., I-II, Q. viii, a. 1; Quæst. disputatæ, De veritate, Q. xxii, a. 1). It is found in all beings, even in those that are unconscious. The inclination to what is good and suitable, and consequently the aversion to what is evil - for the avoidance of evil is a good - are included in it. It may be directed towards an object that is absent or towards one that is actually present. Finally, in conscious beings, it is not restricted to organic needs or lower tendencies, but extends to the highest and noblest aspirations. Two main kinds of appetite are recognized by the scholastics; one unconscious, or naturalis; the other conscious, or elicitus, subdivided into sensitive and rational. From their very nature, all beings have certain tendencies, affinities, and forms of activity. The term natural appetite includes all these. It means the inclination of a thing to that which is in accord with its nature, without any knowledge of the reason why such a thing is appetible. This tendency originates immediately in the nature of each being, and remotely in God, the author of that nature (Quæst. disp., De veritate, Q. xxv, art. 1). The appetitus elicitus follows knowledge. Knowledge is the possession by the mind of an object in its ideal form, whereas appetite is the tendency towards the thing thus known, but considered in its objective reality (Quæst. disp., De veritate, Q. xxii, a. 10). But as knowledge is of two specifically different kinds, so also is the appetite (Summa Theol., I, Q. lxxx, a. 2). The appetitus sensitivus, also called animalis, follows sense-cognition. It is an essentially organic faculty; its functions are not functions of the soul alone, but of the body also. It tends primarily "to a concrete object which is useful or pleasurable", not to "the reason itself of its appetibility". The appetitus rationalis, or will, is a faculty of the spiritual soul, following intellectual knowledge, tending to the good as such and not primarily to concrete objects. It tends to these in so far as they are known to participate in the abstract and perfect goodness conceived by the intellect (Quæst. disp., De veritate, Q. xxv, a. 1). In the natural and the sensitive appetites there is no freedom. One is necessitated by the laws of nature itself, the other by the sense-apprehension of a concrete thing as pleasant and useful. The will, on the contrary, is not necessitated by any concrete good, because no concrete good fully realizes the concept of perfect goodness which alone can necessarily draw the will. In this is to be found the fundamental reason of the freedom of the will (cf. Quæst. disp., De veritate, Q. xxv, a. 1). The sensitive appetite is divided into appetitus concupiscibilis and appetitus irascibilis, according as its object is apprehended simply as good, useful, or pleasurable, or as being obtainable only with difficulty and by the overcoming of obstacles (Summa Theol., I, Q. lxxxi, a. 5; Q. lxxxii, a. 5; I-II, Q. xxiii, a. 1; Quæst. disp., De veritate, Q. xxv, a. 2). All the manifestations of the sensitive appetite are called passions. In the scholastic terminology this word has not the limited signification in which it is commonly used to-day. There are six passions for the concupiscible appetite: love and hatred, desire and aversion, joy and sadness; and five for the irascible appetite: hope and despair, courage, fear, and anger (Summa Theol., I-II, Q. xxiii, a. 4).

In man are found the natural, the sensitive, and the rational appetites. Certain of man's natural tendencies have in view his own personal interest. e.g. conservation of life, health, physical and mental welfare and perfection. Some of them regard the interest of other men, and some relate to God. Such inclinations, however, although springing immediately from human nature, become conscious and deliberate in many of their determinations (Summa Theol., I, Q. lx, a. 3, 4, 5). The tendency of the various faculties to perform their appropriate functions is also a natural appetite, but not a distinct faculty (Summa Theol., I, Q. lxxx, art. 1, ad 3; Q. lxxviii, art. 1, ad 3am). The sensitive appetite in man is under the control of the will and can be strengthened or checked by the will's determination. This control, however, is not absolute, for the sensitive appetite depends on organic conditions, which are not regulated by reason. Frequently, also, owing to its suddenness or intensity, the outburst of passion cannot be repressed (Summa Theol., I, Q. lxxxi, a. 3; I-II, Q. xvii, a. 7; Quæst. disp., De veritate, Q. xxv, a. 4). On the other hand, the sensitive appetite exerts a strong influence on the will, both because the passions modify organic conditions and thus influence all cognitive faculties, and because their intensity may prevent the mind from applying itself to the higher operations of intellect and will (Summa Theol., I-II, Q. ix, a. 2; Q. x, a. 3; Q. lxxvii, a. 1). The theory of appetite has various applications in theology. lt affects the solution of such problems as man's desire for God, the consequences of original sin, and the perfection of Christ's humanity. It is of importance also in questions concerning the natural moral law, responsibility, virtue, and vice, the influence of passion as a determinant of human action. Among the medieval theologians, St. Thomas held that intelligent creatures desire naturally to behold the essence of God. The knowledge which they have of Him through His effects serves only to quicken their desire for immediate vision. Scotus, while admitting this desire as a natural tendency in man, claimed that it could not be realized without the assistance of grace. The discussion of the problem was continued by the commentators of St. Thomas, and it has been revived by modern theologians. Cf. Sestili, "De naturali intelligentis animæ appetitu intuendi divinam essentiam" (Rome, 1896).

MAHER, Psychology (4th ed., London, 1900); MERCIER, Psychologie (6th ed., Louvain, 1903); GARDAIR, Les passions et la volonté (Paris, 1892); cf. also GARDEIL in Dict. de théol. cath., s. v. Appétit.

C.A. DUBRAY