Seemingly contradictory to the logical studies of happiness that had been going on for several years, Jean Piaget sought to bridge these two perspectives. In a remarkable series of experiments in his earliest years of clinical work, Piaget demonstrated that a child's awareness, anxiety, and happiness were distinctly interconnected. With the encouragement of Sigmund Freud and Alfred Adler, Piaget believed that children had to learn the things that adults did not want to learn: the critical consciousness of suffering, the agony of frustration, the anxiety of being uncertain. Piaget distinguished between "critical consciousness," which is what modern critical psychology is founded on, and the concepts that "Happiness" and "Anxiety" are derived from, which appear in childhood, are not meaningful, and go back to classical Greece.