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 policy 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.