And yet, as we have indicated, the thing, whatever it is, is certainly by no means insubstantial and unreal. Nothing seems indeed more certain than that in this strange revolution in the relations of two people to each other—called “falling in love”—and behind all the illusions connected with it, _something is happening_, something very real, very important. The falling-in-love may be reciprocal, or it may be onesided; it may be successful, or it may be unsuccessful; it may be only a surface indication of other and very different events; but anyhow, deep down in the sub-conscious world, _something_ is happening. It may be that two unseen and only dimly suspected existences are becoming really and permanently united; it may be that for a certain period, or (what perhaps comes to the same thing) that to a certain _depth_, they are transfusing and profoundly modifying each other; it may be that the mingling of elements and the transformation is taking place almost entirely in one person, and only to a slight degree or hardly at all in the other; yet in all these cases—beneath the illusions, the misapprehensions, the mirage and the _maya_, the surface satisfactions and the internal disappointments—something very real is happening, an important growth and evolution is taking place. To understand this phenomenon in some slight degree, to have some inkling of the points of the compass by which to steer over this exceedingly troubled sea, is, one might say, indispensable for every youthful human creature; but alas! the instruction is not provided—for indeed, as things are to-day, the adult and the mature are themselves without knowledge, and their eyes without speculation on the subject. Treatises on the Art of Love truly exist—and some (for the field they cover) very good ones, like the _Ars Amatoria_ of Ovid or the _Kama-sutra_ of Vatsayana; but they are concerned mainly or wholly with the details and technicalities of the subject—with the conduct of intrigues and amours, with times and seasons, positions and preparations, unguents and influences. It is like instructions given to a boatman on the minutiæ of his craft—how to contend with wind and wave, how to use sail and oar, to steer, to tack, to luff to a breaker, and so forth; all very good and necessary in their way, but who is there to point us our course over the great Ocean, and the stars by which to direct it? The later works on this great subject—though not despising the more elementary aspects—will no doubt have to proceed much farther, into the deep realms of psychology, biological science, and ultimately of religion.[20]