This article attempts to carry further the discussion of some aspects of the issues of the analysis of relations between African traditional thought and Western concepts of causation presented by Robin Horton (1967) in earlier articles in this journal. It will also be clear to some readers that its title has been inspired by the theme of Sir Karl Popper's two-volume work, The Open Society and Its Enemies, which first appeared in 1945. In this work Popper makes a systematic attack on modern totalitarians and their predecessors, and in so doing contrasts two types of societies, ‘the open society’, which is the ideal aspired to by liberal democrats, and ‘the closed society’, which he equates with tribalism; and it is to a form of this tribalism, he contends, that the totalitarians would have us return. Popper belongs to a long line of thinkers, including philosophers, lawyers, economists, and sociologists, who have used tribal or so-called primitive man—or rather their conceptions of him—as a means of illuminating their analysis of the problems of society in general and of modern society in particular, and in so doing have often raised the hackles of social anthropologists, who, by virtue of having lived in non-literate societies, tend to consider themselves the profession most likely to know something about the people whom their social-science colleagues cite with deceptive facility. It so happens, I believe, that Popper's conception of tribal or primitive man implied in his picture of ‘the closed society’ is much nearer the mark than, say, Hobbes's picture of man in ‘the state of nature’ or of Rousseau's idea of ‘the noble savage’.