Both these types are to my judgment obviously unsatisfactory. The ideal organization of the mind must be one in which first there is a minimum of waste of energy, secondly a maximum realization of potentiality. The operations of mind may further be thought of from two different angles--a subserving the biological needs of the organism, or as ends in themselves. From the first point of view, thought is action _in posse_: efficiency and full utilization of energy are here the requirements, and it is obvious that any method which even partially separates one part of the mental organization from the rest must be a poor one, that a refusal to face any portion of reality, such as, in our special case, the physical side of sex, must put the organism at a disadvantage in a world in which that portion of reality plays, as it obviously does, an important rôle. The correct type of organization is one of the type which has been developed over and over again in the course of evolution, for different functions: it is the hierarchical one, in which some parts are dominant, others subordinate, the dominant parts helpless without the subordinate, the subordinate different, through the fact of their subordination, from what they would otherwise have been, doing most of the hard work, but under the guidance of the dominant. Only in this way is a unitary organization arrived at in which there is the minimum of waste, of antagonism between the parts. The psycho-analysts have, by analysing the pathology of mind, shown us how waste of energy may arise in particular cases, and so make it easier for us to avoid it in general.