This paper points out the limitations of the risk mitigation approach centered on "responsible AI" in AI regulatory discourse and proposes a social impact assessment framework that utilizes the concept of freedom to systematically examine the social impacts of AI. Drawing on Kantian philosophy and its contemporary interpretation, it defines freedom as the counterpart of responsibility and proposes two dimensions: freedom as a capability and freedom as an opportunity. Applying this framework to the Sustainable Development Goals (SDGs), it develops a prototype framework that systematically considers the social impacts of AI. This framework complements existing risk-based approaches and presents a first step toward realizing the concept of freedom in policymaking.