Abstract: After briefly presenting the concepts of orthodox, mainstream and heterodox economics, and applying them to the contemporary period, this article discusses the Post Keynesian school and its relation to contemporary orthodox and mainstream economics. While opposed to the neoclassical orthodoxy, the Post Keynesian school has some positive unifying ideas, although some internal tensions remain. There are also some overlaps between Post Keynesianism and other approaches, and a careful combination of contributions from different approaches and different disciplines is not only possible, but also necessary. Post Keynesianism is located outside current mainstream economics, although this argument partly depends on a more precise specification of the concept of uncertainty. The non-mainstream character of Post Keynesian economics has at least two types of important implications. The first involves the approach's ability to influence the economy and the danger of ‘the scholastic fallacy’; the second refers to a reproductive difficulty inside academia Ver menos