It will be seen that the definition of chastity remains somewhat lacking in precision. That is inevitable. We cannot grasp purity tightly, for, like snow, it will merely melt in our hands. "Purity itself forbids too minute a system of rules for the observance of purity," well says Sidgwick (_Methods of Ethics_, Bk. iii, Ch. IX). Elsewhere (op. cit., Bk. iii, Ch. XI) he attempts to answer the question: What sexual relations are essentially impure? and concludes that no answer is possible. "There appears to be no distinct principle, having any claim to self-evidence, upon which the question can be answered so as to command general assent." Even what is called "Free Love," he adds, "in so far as it is earnestly advocated as a means to a completer harmony of sentiment between men and women, cannot be condemned as impure, for it seems paradoxical to distinguish purity from impurity merely by less rapidity of transition." Moll, from the standpoint of medical psychology, reaches the same conclusion as Sidgwick from that of ethics. In a report on the "Value of Chastity for Men," published as an appendix to the third edition (1899) of his _Konträre Sexualempfindung_, the distinguished Berlin physician discusses the matter with much vigorous common sense, insisting that "chaste and unchaste are _relative ideas_." We must not, he states, as is so often done, identify "chaste" with "sexually abstinent." He adds that we are not justified in describing all extra-marital sexual intercourse as unchaste, for, if we do so, we shall be compelled to regard nearly all men, and some very estimable women, as unchaste. He rightly insists that in this matter we must apply the same rule to women as to men, and he points out that even when it involves what may be technically adultery sexual intercourse is not necessarily unchaste. He takes the case of a girl who, at eighteen, when still mentally immature, is married to a man with whom she finds it impossible to live and a separation consequently occurs, although a divorce may be impossible to obtain. If she now falls passionately in love with a man her love may be entirely chaste, though it involves what is technically adultery.