This evolutionary moment gives the complete type of love. As it goes on, a breach of equilibrium is produced at the expense of the physiological and instinctive elements, which gradually efface themselves before a more and more intellectualised image. Certainly, there lies at the root of all love the unconscious search for an ideal, but for an ideal perceived in a concrete, personal form, incarnate for the moment in an individual. By a process of mental abstraction similar to that which draws from perceptions the most general ideas, the concrete image is transformed into a vague scheme, a concept, an absolute ideal, and we have a purely intellectual, Platonic, mystical love; the emotion is totally intellectualised. Let us remark that this last stage of evolution is not so very rare. Not only do we meet with it sporadically, but it has been fixed and expressed, at certain moments of history, in institutions, such as the chivalric love, of which Geoffrey Rudel seeking the Lady of Tripoli is the most perfect example; the troubadours, the Provençal Courts of Love, deciding that true love cannot exist in marriage, and excludes all cohabitation, etc. We must not, however, allow ourselves to be misled by appearances. Platonic and mystic lovers have always maintained that their sentiment is perfectly pure, and has nothing in common with the senses; the contrary opinion seeming to them a profanation and a sacrilege. Yet how could love exist without physical conditions, however attenuated we may suppose them? If they are wanting, all we have or can have is a purely intellectual state, the representation of an ideal conceived but not felt. Besides, we have more satisfactory evidence than suppositions and arguments; facts of tolerably frequent occurrence show how rapidly we may fall from the ideal plane. It is only because all the circumstances are in its favour that the fall is so easy.[160] Footnote 160: For some curious observations on this point see especially Moreau (of Tours), _Psychologie morbide_, pp. 264-278.