Summa Theologica, by St. Thomas Aquinas, [1947], at sacred-texts.com
We have now to consider the soul's passions in particular, and (1) the passions of the concupiscible faculty; (2) the passions of the irascible faculty.
The first of these considerations will be threefold: since we shall consider (1) Love and hatred; (2) Desire and aversion; (3) Pleasure and sadness.
Concerning love, three points must be considered: (1) Love itself; (2) The cause of love; (3) The effects of love. Under the first head there are four points of inquiry:
(1) Whether love is in the concupiscible power?
(2) Whether love is a passion?
(3) Whether love is the same as dilection?
(4) Whether love is properly divided into love of friendship, and love of concupiscence?
Objection 1: It would seem that love is not in the concupiscible power. For it is written (Wis. 8:2): "Her," namely wisdom, "have I loved, and have sought her out from my youth." But the concupiscible power, being a part of the sensitive appetite, cannot tend to wisdom, which is not apprehended by the senses. Therefore love is not in the concupiscible power.
Objection 2: Further, love seems to be identified with every passion: for Augustine says (De Civ. Dei xiv, 7): "Love, yearning for the object beloved, is desire; having and enjoying it, is joy; fleeing what is contrary to it, is fear; and feeling what is contrary to it, is sadness." But not every passion is in the concupiscible power; indeed, fear, which is mentioned in this passage, is in the irascible power. Therefore we must not say absolutely that love is in the concupiscible power.
Objection 3: Further, Dionysius (Div. Nom. iv) mentions a "natural love." But natural love seems to pertain rather to the natural powers, which belong to the vegetal soul. Therefore love is not simply in the concupiscible power.
On the contrary, The Philosopher says (Topic. ii, 7) that "love is in the concupiscible power."
I answer that, Love is something pertaining to the appetite; since good is the object of both. Wherefore love differs according to the difference of appetites. For there is an appetite which arises from an apprehension existing, not in the subject of the appetite, but in some other: and this is called the "natural appetite." Because natural things seek what is suitable to them according to their nature, by reason of an apprehension which is not in them, but in the Author of their nature, as stated in the FP, Q[6], A[1], ad 2; FP, Q[103], A[1], ad 1,3. And there is another appetite arising from an apprehension in the subject of the appetite, but from necessity and not from free-will. Such is, in irrational animals, the "sensitive appetite," which, however, in man, has a certain share of liberty, in so far as it obeys reason. Again, there is another appetite following freely from an apprehension in the subject of the appetite. And this is the rational or intellectual appetite, which is called the "will."
Now in each of these appetites, the name "love" is given to the principle movement towards the end loved. In the natural appetite the principle of this movement is the appetitive subject's connaturalness with the thing to which it tends, and may be called "natural love": thus the connaturalness of a heavy body for the centre, is by reason of its weight and may be called "natural love." In like manner the aptitude of the sensitive appetite or of the will to some good, that is to say, its very complacency in good is called "sensitive love," or "intellectual" or "rational love." So that sensitive love is in the sensitive appetite, just as intellectual love is in the intellectual appetite. And it belongs to the concupiscible power, because it regards good absolutely, and not under the aspect of difficulty, which is the object of the irascible faculty.
Reply to Objection 1: The words quoted refer to intellectual or rational love.
Reply to Objection 2: Love is spoken of as being fear, joy, desire and sadness, not essentially but causally.
Reply to Objection 3: Natural love is not only in the powers of the vegetal soul, but in all the soul's powers, and also in all the parts of the body, and universally in all things: because, as Dionysius says (Div. Nom. iv), "Beauty and goodness are beloved by all things"; since each single thing has a connaturalness with that which is naturally suitable to it.
Objection 1: It would seem that love is not a passion. For no power is a passion. But every love is a power, as Dionysius says (Div. Nom. iv). Therefore love is not a passion.
Objection 2: Further, love is a kind of union or bond, as Augustine says (De Trin. viii, 10). But a union or bond is not a passion, but rather a relation. Therefore love is not a passion.
Objection 3: Further, Damascene says (De Fide Orth. ii, 22) that passion is a movement. But love does not imply the movement of the appetite; for this is desire, of which movement love is the principle. Therefore love is not a passion.
On the contrary, The Philosopher says (Ethic. viii, 5) that "love is a passion."
I answer that, Passion is the effect of the agent on the patient. Now a natural agent produces a twofold effect on the patient: for in the first place it gives it the form; and secondly it gives it the movement that results from the form. Thus the generator gives the generated body both weight and the movement resulting from weight: so that weight, from being the principle of movement to the place, which is connatural to that body by reason of its weight, can, in a way, be called "natural love." In the same way the appetible object gives the appetite, first, a certain adaptation to itself, which consists in complacency in that object; and from this follows movement towards the appetible object. For "the appetitive movement is circular," as stated in De Anima iii, 10; because the appetible object moves the appetite, introducing itself, as it were, into its intention; while the appetite moves towards the realization of the appetible object, so that the movement ends where it began. Accordingly, the first change wrought in the appetite by the appetible object is called "love," and is nothing else than complacency in that object; and from this complacency results a movement towards that same object, and this movement is "desire"; and lastly, there is rest which is "joy." Since, therefore, love consists in a change wrought in the appetite by the appetible object, it is evident that love is a passion: properly so called, according as it is in the concupiscible faculty; in a wider and extended sense, according as it is in the will.
Reply to Objection 1: Since power denotes a principle of movement or action, Dionysius calls love a power, in so far as it is a principle of movement in the appetite.
Reply to Objection 2: Union belongs to love in so far as by reason of the complacency of the appetite, the lover stands in relation to that which he loves, as though it were himself or part of himself. Hence it is clear that love is not the very relation of union, but that union is a result of love. Hence, too, Dionysius says that "love is a unitive force" (Div. Nom. iv), and the Philosopher says (Polit. ii, 1) that union is the work of love.
Reply to Objection 3: Although love does not denote the movement of the appetite in tending towards the appetible object, yet it denotes that movement whereby the appetite is changed by the appetible object, so as to have complacency therein.
Objection 1: It would seem that love is the same as dilection. For Dionysius says (Div. Nom. iv) that love is to dilection, "as four is to twice two, and as a rectilinear figure is to one composed of straight lines." But these have the same meaning. Therefore love and dilection denote the same thing.
Objection 2: Further, the movements of the appetite differ by reason of their objects. But the objects of dilection and love are the same. Therefore these are the same.
Objection 3: Further, if dilection and love differ, it seems that it is chiefly in the fact that "dilection refers to good things, love to evil things, as some have maintained," according to Augustine (De Civ. Dei xiv, 7). But they do not differ thus; because as Augustine says (De Civ. Dei xiv, 7) the holy Scripture uses both words in reference to either good or bad things. Therefore love and dilection do not differ: thus indeed Augustine concludes (De Civ. Dei xiv, 7) that "it is not one thing to speak of love, and another to speak of dilection."
On the contrary, Dionysius says (Div. Nom. iv) that "some holy men have held that love means something more Godlike than dilection does."
I answer that, We find four words referring in a way, to the same thing: viz. love, dilection, charity and friendship. They differ, however, in this, that "friendship," according to the Philosopher (Ethic. viii, 5), "is like a habit," whereas "love" and "dilection" are expressed by way of act or passion; and "charity" can be taken either way.
Moreover these three express act in different ways. For love has a wider signification than the others, since every dilection or charity is love, but not vice versa. Because dilection implies, in addition to love, a choice [electionem] made beforehand, as the very word denotes: and therefore dilection is not in the concupiscible power, but only in the will, and only in the rational nature. Charity denotes, in addition to love, a certain perfection of love, in so far as that which is loved is held to be of great price, as the word itself implies [*Referring to the Latin "carus" (dear)].
Reply to Objection 1: Dionysius is speaking of love and dilection, in so far as they are in the intellectual appetite; for thus love is the same as dilection.
Reply to Objection 2: The object of love is more general than the object of dilection: because love extends to more than dilection does, as stated above.
Reply to Objection 3: Love and dilection differ, not in respect of good and evil, but as stated. Yet in the intellectual faculty love is the same as dilection. And it is in this sense that Augustine speaks of love in the passage quoted: hence a little further on he adds that "a right will is well-directed love, and a wrong will is ill-directed love." However, the fact that love, which is concupiscible passion, inclines many to evil, is the reason why some assigned the difference spoken of.
Reply to Objection 4: The reason why some held that, even when applied to the will itself, the word "love" signifies something more Godlike than "dilection," was because love denotes a passion, especially in so far as it is in the sensitive appetite; whereas dilection presupposes the judgment of reason. But it is possible for man to tend to God by love, being as it were passively drawn by Him, more than he can possibly be drawn thereto by his reason, which pertains to the nature of dilection, as stated above. And consequently love is more Godlike than dilection.
Objection 1: It would seem that love is not properly divided into love of friendship and love of concupiscence. For "love is a passion, while friendship is a habit," according to the Philosopher (Ethic. viii, 5). But habit cannot be the member of a division of passions. Therefore love is not properly divided into love of concupiscence and love of friendship.
Objection 2: Further, a thing cannot be divided by another member of the same division; for man is not a member of the same division as "animal." But concupiscence is a member of the same division as love, as a passion distinct from love. Therefore concupiscence is not a division of love.
Objection 3: Further, according to the Philosopher (Ethic. viii, 3) friendship is threefold, that which is founded on "usefulness," that which is founded on "pleasure," and that which is founded on "goodness." But useful and pleasant friendship are not without concupiscence. Therefore concupiscence should not be contrasted with friendship.
On the contrary, We are said to love certain things, because we desire them: thus "a man is said to love wine, on account of its sweetness which he desires"; as stated in Topic. ii, 3. But we have no friendship for wine and suchlike things, as stated in Ethic. viii, 2. Therefore love of concupiscence is distinct from love of friendship.
I answer that, As the Philosopher says (Rhet. ii, 4), "to love is to wish good to someone." Hence the movement of love has a twofold tendency: towards the good which a man wishes to someone (to himself or to another) and towards that to which he wishes some good. Accordingly, man has love of concupiscence towards the good that he wishes to another, and love of friendship towards him to whom he wishes good.
Now the members of this division are related as primary and secondary: since that which is loved with the love of friendship is loved simply and for itself; whereas that which is loved with the love of concupiscence, is loved, not simply and for itself, but for something else. For just as that which has existence, is a being simply, while that which exists in another is a relative being; so, because good is convertible with being, the good, which itself has goodness, is good simply; but that which is another's good, is a relative good. Consequently the love with which a thing is loved, that it may have some good, is love simply; while the love, with which a thing is loved, that it may be another's good, is relative love.
Reply to Objection 1: Love is not divided into friendship and concupiscence, but into love of friendship, and love of concupiscence. For a friend is, properly speaking, one to whom we wish good: while we are said to desire, what we wish for ourselves.
Hence the Reply to the Second Objection.
Reply to Objection 3: When friendship is based on usefulness or pleasure, a man does indeed wish his friend some good: and in this respect the character of friendship is preserved. But since he refers this good further to his own pleasure or use, the result is that friendship of the useful or pleasant, in so far as it is connected with love of concupiscence, loses the character to true friendship.