Mainstream views concerning the uselessness or usefulness of HET are illustrated. These rely on a hidden assumption: a 'cumulative view' according to which the provisional point of arrival of contemporary economics incorporates all previous contributions in an improved way. Critiques of positivism led philosophy of science to recognise the existence of different approaches – in economics, as in other sciences. Conceptualisation, recognised by Schumpeter as the first stage in economic theorising, is the stage in which the different visions of the (...) world underlying the different approaches, take shape – and are better recognised. In this, HET plays an essential role. As an illustration, the differences between the classical and marginalist conceptualisations of the economy are illustrated. Thus HET is essential in both undergraduate and graduate economic curricula, as a decisive help towards a better understanding and evaluation of formalised theories/models in the first case, and as an education to the philological method of research, essential in the first stage of theorising, in the case of graduate curricula. (shrink)