Transitioning into a circular economy (CE) has been recently proposed as an agenda for reconciling global industrial systems with natural equilibria, but the current understanding of CE is ambiguous among scholars. Informed by recent growing CE literature, this study summarizes through three key propositions a set of indisputable insights emerging from the CE debate. In particular, the paper: remarks how CE takes stock of concepts of other schools of thought to drive policy interventions; depicts CE as a systemic transition of global industrial systems; and highlights the role of eco-effectiveness to upgrade business-centered approaches to sustainability. The proposed propositions are expected to contribute to reducing ambiguities in the CE debate and to convey coherence to future research.