Keynes, Kalecki, Sraffa: Coherence?

This paper, in honour of John King, addresses the question raised by him in his A History of Post-Keynesian since 1936, reflected in the title. Initial surveys of post-Keynesian economics defined it in term of the Keynesian, Kaleckian and Sraffian strands. However, subsequently, it has become less clear that the Sraffian stream should be included under the ‘broad church’ known as post-Keynesian economics. Serious and irreconcilable methodological differences exist between Sraffians and post-Keynesians about the validity of comparisons of long-run equilibrium positions, the role of historical time and the importance of uncertainty.