 Hull (1988) argued that the success of science can be explained by an invisible hand mechanism rather than in terms of rational decision-making. He did not deny that most scientists regard themselves as rational truth seekers, but on his account the primary motivation is the drive for professional recognition and credit via positive citation by others, and avoidance of violations of institutionalized standards. The term ‘rationality’ does not even appear in the book’s index. Nonetheless, the institutional incentive structure of science works to produce generally reliable results and scientific progress, so that, to rationality-minded philosophers, science looks as if it is driven by the intentional rationality of its practitioners. We might say that, for Hull, rationality explains nothing without causal backing, but once we bring the causal mechanisms into play, there is no longer a need to foreground rationality, at least not intentional rationality.