# Treatise of Human Nature/Book 2: Of the passions/Part 2/Section 11

SECTION XI.
Of the amorous passion, or love betwixt the sexes.
Of all the compound passions, which proceed from a mixture of love and hatred with other affections, no one better deserves our attention, than that love, which arises betwixt the sexes, as well on account of its force and violence, as those curious principles of philosophy, for which it affords us an incontestable argument. 'Tis plain, that this affection, in its most natural state, is deriv'd from the conjunction of three different impressions or passions, viz. The pleasing sensation arising from beauty; the bodily appetite for generation; and a generous kindness or good-will. The origin of kindness from beauty may be explain'd from the foregoing reasoning. The question is how the bodily appetite is excited by it.
The appetite of generation, when confin'd to a certain degree, is evidently of the pleasant kind, and has a strong connexion with all the agreeable emotions. Joy, mirth, vanity, and kindness are all incentives to this desire; as well as music, dancing, wine, and good cheer. On the other hand, sorrow, melancholy, poverty, humility are destructive of it. From this quality 'tis easily conceiv'd why it shou'd be connected with the sense of beauty.
But there is another principle that contributes to the same effect. I have observ'd that the parallel direction of the desires is a real relation, and no less than a resemblance in their sensation, produces a connexion among them. That we may fully comprehend the extent of this relation, we must consider, that any principal desire may be attended with subordinate ones, which are connected with it, and to which if other desires are parallel, they are by that means related to the principal one. Thus hunger may oft be consider'd as the primary inclination of the soul, and the desire of ​approaching the meat as the secondary one; since 'tis absolutely necessary to the satisfying that appetite. If an object, therefore by any separate qualities, inclines us to approach the meat, it naturally encreases our appetite; as on the contrary, whatever inclines us to set our victuals at a distance, is contradictory to hunger, and diminishes our inclination to them. Now 'tis plain that beauty has the first effect, and deformity the second: Which is the reason why the former gives us a keener appetite for our victuals, and the latter is sufficient to disgust us at the most savoury dish, that cookery has invented. All this is easily applicable to the appetite for generation.
From these two relations, viz. resemblance and a parallel desire, there arises such a connexion betwixt the sense of beauty, the bodily appetite, and benevolence, that they become in a manner inseparable: And we find from experience, that 'tis indifferent which of them advances first; since any of them is almost sure to be attended with the related affections. One, who is inflam'd with lust, feels at least a momentary kindness towards the object of it, and at the same time fancies her more beautiful than ordinary; as there are many, who begin with kindness and esteem for the wit and merit of the person, and advance from that to the other passions. But the most common species of love is that which first arises from beauty, and afterwards diffuses itself into kindness and into the bodily appetite. Kindness or esteem, and the appetite to generation, are too remote to unite easily together. The one is, perhaps, the most refin'd passion of the soul; the other the most gross and vulgar. The love of beauty is plac'd in a just medium betwixt them, and partakes of both their natures: From whence it proceeds, that 'tis so singularly fitted to produce both.
This account of love is not peculiar to my system, but is unavoidable on any hypothesis. The three affections, which compose this passion, are evidently distinct, and has each of ​them its distinct object. 'Tis certain, therefore, that 'tis only by their relation they produce each other. But the relation of passions is not alone sufficient. 'Tis likewise necessary, there shou'd be a relation of ideas. The beauty of one person never inspires us with love for another. This then is a sensible proof of the double relation of impressions and ideas From one instance so evident as this we may form a judgment of the rest.
This may also serve in another view to illustrate what I have insisted on concerning the origin of pride and humility, love and hatred I have observ'd, that tho' self be the object of the first set of passions, and some other person of the second, yet these objects cannot alone be the causes of the passions; as having each of them a relation to two contrary affections, which must from the very first moment destroy each other. Here then is the situation of the mind, as I have already describ'd it. It has certain organs naturally fitted to produce a passion; that passion, when produc'd, naturally tums the view to a certain object. But this not being sufficient to produce the passion, there is requir'd some other emotion, which by a double relation of impressions and ideas may set these principles in action, and bestow on them their first impulse. This situation is still more remarkable with regard to the appetite of generation. Sex is not only the object, but also the cause of the appetite. We not only turn our view to it, when actuated by that appetite; but the reflecting on it suffices to excite the appetite. But as this cause loses its force by too great frequency, 'tis necessary it shou'd be quicken'd by some new impulse; and that impulse we find to arise from the beauty of the person; that is, from a double relation of impressions and ideas. Since this double relation is necessary where an affection has both a distinct cause, and object, how much more so, where it has only a distinct object, without any determinate cause?