The chapter investigates the 2017–2018 Finnish basic income (BI) trial as an example of experimental policymaking fostered by ideas from behavioral economics. The BI trial is used as a window through which emerging ideas of experimental society are explored within a broader historical, cultural, and political framework. The chapter contextualizes and historicizes the two tenets of behavioral economics: nudge theory, and utilizing randomized controlled trials (RCTs) in evidence-based policymaking. The analysis offers a new perspective on the ways RCTs have changed from a medical research method to an all-around philosophy for testing, learning, and adapting. Societal experiments enforce precise science–society configurations. In the BI trial, the Finnish government turned its social security agency into a quasi-experimental laboratory where the “disease” under investigation was unemployment and the “medicine” was BI. The BI experiment evidenced that the ideals of an experimental society evolve with the assistance of epidemiological concepts such as risk, population, and health. This chapter concludes by stating that the scientization of politics obscures the boundaries between medical and societal experiments as if unemployment were a purely scientific, not a political, issue.