It is because they imply the sacrifice of a more or less advantageous position to a purely private happiness that, as a general rule, "impossible" marriages are the happiest of all. (One cannot very well include among the "impossible" marriages those that are made for money, there being no instance on record of a couple, of whom the wife or even the husband has thus sold himself, who have not sooner or later been admitted into society, if only by tradition, and on the strength of so many precedents, and so as not to have two conflicting standards.) Perhaps, on the other hand, the artistic, if not the perverse side of Swann's nature would in any event have derived a certain amount of pleasure from coupling with himself, in one of those crossings of species such as Mendelians practise and mythology records, a creature of a different race, archduchess or prostitute, from contracting a royal alliance or from marrying beneath him.