© The Author 2016. Published by Oxford University Press on behalf of the Cambridge Political Economy Society. All rights reserved. We draw on the seminal contribution to economics by Luigi Pasinetti, respond to his call to reverse what he saw as the 'original sin' of classical economists exacerbated by neoclassical economists, namely the assumption of non-increasing returns to scale, and move towards building a post-classical economics. We outline the contours of a post-classical framework that draws on key themes and contributions from Pasinetti on learning, technical progress, increasing returns, resource creation, trade and catching up, and contributions from within and without economics that are in line with, lend support to and challen...