Janet, like Freud, met the problem of explaining why certain people have not conscious memory of past, for them, tremendous experiences, and yet those experiences exert a marked influence on conduct. To account for these facts he assumed the existence of a force inherent in consciousness, enabling this to hold to itself memories of events. A loss of conscious memory of some past tremendous event would thus be due to consciousness being too weak to hold that event to itself—an hypothesis which also explains why great joy can be as disturbing as great sorrow.