 It is clear that Kuhn considered science more efficient on his own account than on Popper’s, because the double process enables extreme specialization (Wray 2011; De Langhe 2014c). Indeed, traditional accounts fail Kuhn’s demarcation criterion—that a genuine science supports a puzzle-solving tradition. Given Kuhn’s conviction that science is progressive in terms of problem-solving success, predictive accuracy, simplicity (the reworking and streamlining of problem-solving efficiency over time), and so on, it supposedly follows that his account makes science both rational and non-relativistic. Critics disagreed.