A reading of Winnicott's writings in reverse chronological order reveals an unacknowledged and significant turning point in his thinking. Based on the unveiling of this development in Winnicottian theory it is proposed that: 1) In his late writings Winnicott shifts from a dualistic to a monistic view of psychic energy. 2) This transition to monistic thinking coincides with unification of the “primitive love impulse” and the “motility impulse” into a single energy source in the “Use of the Object”. 3) The unification of primitive love with motility makes it possible to identify motility as the specific energetic origin of human behavior as a whole and of aggression in particular. 4) Recognition of motility as the primal life-force implies that human beings, upon emerging into the world, are neither “good” or “bad”. 5) A four-stage-developmental-model anchored in Winnicott's late monistic thinking is suggested. The model links a person's stage of development on the motility axis, his level of separation from object and his expressed form of aggression. 6)“Survival of the object” is not always sufficient when dealing with aggression in analysis. At times, restoring the connection between aggression and the life-force (motility) is needed. This process is demonstrated using a clinical example.