Trifunctional hypothesis
The trifunctional hypothesis of prehistoric Proto-Indo-European society postulates a tripartite ideology (""idéologie tripartite"") reflected in the existence of three classes or castes—priests, warriors, and commoners (farmers or tradesmen)—corresponding to the three functions of the sacral, the martial and the economic, respectively. The trifunctional thesis is primarily associated with the French mythographer Georges Dumézil, who proposed it in 1929 in the book "Flamen-Brahman", and later in "Mitra-Varuna". Three-way division. According to Georges Dumézil (1898–1986), Proto-Indo-European society had three main groups, corresponding to three distinct functions: In the Proto-Indo-European mythology , each social group had its own god or family of gods to represent it and the function of the god or gods matched the function of the group. Many such divisions occur in the history of Indo-European societies: Reception. Supporters of the hypothesis include scholars such as Émile Benveniste, Bernard Sergent and Iaroslav Lebedynsky, the last of whom concludes that "the basic idea seems proven in a convincing way". The hypothesis was embraced outside the field of Indo-European studies by some mythographers, anthropologists and historians such as Mircea Eliade, Claude Lévi-Strauss, Marshall Sahlins, Rodney Needham, Jean-Pierre  Vernant and Georges Duby. On the other hand, Allen concludes that the tripartite division may be an artefact and a selection effect, rather than an organising principle that was used in the societies themselves. Benjamin W. Fortson reports a sense that Dumézil blurred the lines between the three functions and the examples that he gave often had contradictory characteristics, which had caused his detractors to reject his categories as nonexistent. John Brough surmises that societal divisions are common outside Indo-European societies as well and so the hypothesis has only limited utility in illuminating prehistoric Indo-European society. Cristiano Grottanelli  states that while Dumézilian trifunctionalism may be seen in modern and medieval contexts, its projection onto earlier cultures is mistaken. Belier is strongly critical. The hypothesis has been criticised by the historians Carlo Ginzburg, Arnaldo Momigliano and Bruce Lincoln as being based on Dumézil's sympathies with the political right. Guy Stroumsa sees those criticisms as unfounded.