(b) In its particular sense, charity refers to divine love, that is, to the love of God for man or the love of man for God. Here we are considering charity as the virtue by which the creature loves God for His own sake, and others on account of God.
1106. Love in general is the inclination towards a suitable good, or what is considered as one’s good. It is the root of all appetites of the soul, and hence the importance that the object of love be a true good.
(a) Every attraction is based on the recognition of some suitability in a certain good that attracts, and so is based on love. Example: Love may result from desire, as when from a desire of money springs love of the giver of money; but in the last analysis it will be found that the desire itself came from a previous love, for a person would not wish for money, unless he saw in it some advantage which inclined him towards its possession.
(b) Every repulsion is based on the fact that a certain thing is opposed to that which is suitable for self, and hence results from love. Example: Love sometimes is an effect of hate, as when one loves A because he hates A’s enemies; nevertheless, hate is basically always the result of some love, for one hates only those things that impede or destroy what one loves.
(c) Every satisfaction is due to the possession or presence of something helpful or congenial, and so it presupposes love. Example: A particular satisfaction may cause love, as when one loves a person because his company is entertaining; but the satisfaction is due to the love one has of being entertained.
1107. The effects of love are two; (a) union of affection, for the lover regards the object of love as another self and desires its presence; he delights to think of it and wishes what it wishes; (b) separation from other things, for the lover’s thoughts are on the object of his love, and he is jealous of anything that might take it from him.
1108. Several degrees of love may be distinguished:
(a) Natural love is the tendency of things to their ends which results, not from knowledge, but from nature, and which is found in the irrational and inanimate as well as in higher forms of being. Thus, we may say that fire loves to burn, that every being loves its own existence;
(b) Sense love (_amor_) is the attraction that follows on knowledge obtained through the senses, and that exists in the brutes as well as in man. Thus, a dog loves bones, a cat loves fish. Sex-attraction is a species of sense love;
(c) Rational love (_dilectio_) arises from the reflection of the mind, and is a choice based on the judgment of the reason concerning the worth of the beloved object.