Duncker did finish an article on ethical relativity and the psychology of ethics, which was published in 1939 in Mind. In that article, Duncker ( 1939a) offered difficult but intriguing criticisms of the standard arguments for ethical relativism and, like his mentors Köhler and Wertheimer, opted for a position of ethical invariance that "does not apply to any given historical content of morality, but exclusively to the relationship between ethical variation and situational meanings" (p. 51). Duncker's discussion ranges across a variety of examples, including the practice of collecting interest on debts, clothing styles, and infanticide, all of which have different ethical interpretations in different cultures. The style of the entire article, one of Duncker's last publications, is hauntingly reminiscent of the style of the exercise in psychological anthropology in Wertheimer ( 1912a) account of quantitative reasoning in indigenous people, which was among the first publications of Gestalt psychology.
Despite a time of political and social upheaval that ended in World War II, an unsuccessful marriage that ended in divorce, consuming self-doubt, and severe psychopathology that ended in suicide, Karl Duncker--in his brief life of only 37 years--made substantial contributions in an astonishingly broad array of psychology's subfields. In a now-classic study of eminent contributors to psychology ( Annin, Boring, & Watson, 1968), he received a high rating as one of the more eminent among 500 deceased psychologists. He is recognized today for his creative work in problem solving, cognitive psychology, and the psychology of the perception of apparent movement, and deserves to be recognized as well for his work on pain, the role of past experience in perception, systematic psychology, phenomenology, and motivation. Although much younger than his teachers Kurt Koffka, Wolfgang Köhler, and Max Wertheimer, he died before any of them. More than a half century after his death, Karl Duncker's work remains an inspiring example of responsible, creative, and dedicated psychological scholarship at its best. As Köhler (cited in Duncker, 1945) wrote in the preface to the posthumous publication of the English translation of Duncker's monograph on problem solving, "In Duncker this was the greatest intellectual virtue: He was forever impatient of little things and happy only when he found a way that led to fundamentals. The best we can do in remembering our friend is to give his work as an example which others may follow" (p. iv).
Earlier versions of some of the material in this chapter were presented at conventions in 1991 of the Rocky Mountain Psychological Association and the American Psychological Association.