Reading Winnicott’s writings in reverse order reveals a major unacknowledged turning-point in his thinking. Based on the unveiling of this development it is proposed that: 1) It is only in his late writings that Winnicott makes a wholehearted shift to a monistic view of psychic energy, 2) The paradoxical joining of two opposing forces, taken together with the unification of “primitive love” and “motility” into a single energy source, as suggested in “The use of an object,” was the missing step that enabled Winnicott’s final shift to monistic thinking, 3) This shift allows to identify motility as the energetic origin of human behavior, and 4) Restoring the connection between aggression and motility is a major curative factor.