Arrow did not state SO as a separate condition. He built it into the very notion of a social welfare function, arguing that the result of aggregating preferences will have to be an ordering if it is to “reflect rational choice-making” (Arrow 1951 [1963]: 19). Criticized by Buchanan (1954) for transferring properties of individual choice to collective choice, Arrow in the second edition of Social Choice and Individual Values gave a different rationale. There he argued that transitivity is important because it ensures that collective choices are independent of the path taken to them (Arrow 1951 [1963]: 120). He did not develop this idea further.