As a matter of fact, love determines nothing less than the _establishment of the next generation_. The existence and nature of the _dramatis personae_ who come on to the scene when we have made our exit have been determined by some frivolous love-affair. As the being, the _existentia_ of these future people is conditioned by our instinct of sex in general, so is the nature, the _essentia_, of these same people conditioned by the selection that the individual makes for his satisfaction, that is to say, by love, and is thereby in every respect irrevocably established. This is the key of the problem. In applying it, we shall understand it more fully if we analyse the various degrees of love, from the most fleeting sensation to the most ardent passion; we shall then see that the difference arises from the degree of individualisation of the choice. All the love-affairs of the present generation taken altogether are accordingly the _meditatio compositionis generationis futurae, e qua iterum pendent innumerae generationes_ of mankind. Love is of such high import, because it has nothing to do with the weal or woe of the present individual, as every other matter has; it has to secure the existence and special nature of the human race in future times; hence the will of the individual appears in a higher aspect as the will of the species; and this it is that gives a pathetic and sublime import to love-affairs, and makes their raptures and troubles transcendent, emotions which poets for centuries have not tired of depicting in a variety of ways. There is no subject that can rouse the same interest as love, since it concerns both the weal and woe of the species, and is related to every other which only concerns the welfare of the individual as body to surface. This is why it is so difficult to make a drama interesting if it possesses no love motive; on the other hand, the subject is never exhausted, although it is constantly being utilised.