The paper deals with four interdependent issues: (1) the relationship between “excessive debts” and the occurrence of fi nancial and economic crises throughout history ; (2) the medium to long term impact of economic theory on ideology and economic policy in the context of the systemic crisis of 2008; (3) a critical view of some basic of contemporary economic theory from a philosophical viewpoint; (4) the concept of world governance and the role of the G20 in the aftermath of the 2008 crisis.