The concept of sufficiency has deep philosophical roots, dating back to Ancient Greece. Its emergence as a modern academic framework, however, is more recent.
Philosopher (external link)Harry Frankfurt (external link) (1987) (external link)reintroduced sufficiency as a lower limit-the idea that everyone should have "enough" to live a decent life. The idea simultaneously gained traction in political science. Laura Spengler (external link) (2016) (external link)was among the first to emphasize the need to integrate both social and ecological thresholds into policymaking. Expanding on this, Liam Shields (external link) (2020) (external link) argued for a more complete conception that includes both a lower and upper limit: ensuring everyone has enough while recognizing that excessive consumption can be unjust and unsustainable.
This interdisciplinary evolution culminated in Yamina Saheb's (external link) (2021) widely cited definition:
"Sufficiency is a set of policy measures and daily practices which avoid the demand for energy, materials, land, water, and other natural resources, while delivering wellbeing for all within planetary boundaries."
This framing introduced the sufficiency corridor in which societal well-being is ensured without overshooting ecological boundaries. Thus, moving beyond abstract ideals to define a clear and actionable space where policies and practices can deliver a "good life for all "while maintaining environmental integrity.
The importance of sufficiency was further recognized in the IPCC's Sixth Assessment Report (external link) (2022) (external link), indicating a major step in embedding sufficiency into sustainability science.
Despite growing momentum, recent applications of sufficiency often place disproportionate emphasis on demand reduction, overlooking critical aspects of social justice and basic well-being. Bridging this gap requires interdisciplinary collaboration that integrates normative, technical, and empirical perspectives.
That is precisely the mission of the Sufficiency PhD Days.