Plato has devoted himself more than any one else to the subject of love, especially in the _Symposium_ and the _Phaedrus_; what he has said about it, however, comes within the sphere of myth, fable, and raillery, and only applies for the most part to the love of a Greek youth. The little that Rousseau says in his _Discours sur l'inégalité_ is neither true nor satisfactory. Kant's disquisition on love in the third part of his treatise, _Ueber das Gefühl des Schönen und Erhabenen_, is very superficial; it shows that he has not thoroughly gone into the subject, and therefore it is somewhat untrue. Finally, Platner's treatment of it in his _Anthropology_ will be found by every one to be insipid and shallow. To amuse the reader, on the other hand, Spinoza's definition deserves to be quoted because of its exuberant naïveté: _Amor est titillatio, concomitante idea causae externae_ (_Eth._ iv., prop. 44). It is not my intention to be either influenced or to contradict what has been written by my predecessors; the subject has forced itself upon me objectively, and has of itself become inseparable from my consideration of the world. Moreover, I shall expect least approval from those people who are for the moment enchained by this passion, and in consequence try to express their exuberant feelings in the most sublime and ethereal images. My view will seem to them too physical, too material, however metaphysical, nay, transcendent it is fundamentally. First of all let them take into consideration that the creature whom they are idealising to-day in madrigals and sonnets would have been ignored almost entirely by them if she had been born eighteen years previously.