In this article we demonstrate why and how in the Western science of policymaking a challenge posited by empirical behaviouralism aimed at reforming the over-politicised plicy process along the analytical-rational lines in 1950s did not succeeded. However, it produced a meaningful shift in understanding the policy process and it formed by the 1970s a completely new conceptual context and discourse on the policy process. As a result, by the new millennium the positivist and constructivists perspectives, that are located at the opposite ends of the continuum of methodological presumptions, started to complement each other and even to intermingle at the level of providing practical policy solutions. In the first part we analyse how the cognitive limits and uncertainty of the context forces to re-focus policy analysis from substantive issues to the policy arena design, and to work out conceptions of interactive policymaking. Simultaneously several concepts of constructivist social science (frames, learning, narratives) were applied and adapted in the positivist perspective. We demonstrate why constructivist-interpretivist policy analysis could not for a long time get to the forefront of practical policy analysis. We demonstrate how the application of the pragmatist approach made it possible to develop the conception of design rationality. Overall, we explore the framework in which different methodologies would complement each other in providing policy advice and analysis from different practical angles.