This chapter argues for understanding feasibility as a form of restricted possibility, drawing on Wiens’ (2015) account, and demonstrates its fittingness and relevance to understanding scientific feasibility assessments in the climate context. Feasibility concerns the question of how we can achieve a particular outcome. An outcome is feasible when there is a trajectory from here to the outcome in question that is compatible with the various limitations we face. The chapter begins with four illustrative anecdotes of feasibility judgments made by various actors in the climate policy debate. The chapter then reviews two prominent philosophical accounts of feasibility. The Conditional Probability Account defines feasibility as the probability of success given an agent’s efforts but is critiqued for being too narrow for assessing complex social goals. In contrast, Wiens’ conception of feasibility as restricted possibility – attainability constrained by available resources and processes – captures the pathway-oriented nature of feasibility assessments better in scientific and policy contexts. However, the chapter argues that Wiens’ account faces two unresolved challenges: distinguishing feasibility from mere practical possibility and explaining how we sometimes make meaningful comparative feasibility claims among policy options.