The principal arguments for and against our present energy theory are briefly summarized, after which there follows review and discussion of the concepts of the nature and origin of psychic energy, as well as its vicissitudes in the form of neutralization, fusion, binding, discharge and structure formation. In the course of these discussions the following points are developed:

1Grave theoretical complexities are produced by our attempt to derive almost all the energies of the ego and superego from instinctual sources, and a case can be made for considering each system to have its own inherent energies.