That idle boy who had the temerity to preach caution and to question our curves was Alfred Marshall , who in his inaugural lecture as Professor of Political Economy at Cambridge offered in 1885 the following observation on his subject: 'The fitful and irregular incidents of the market cannot for the greater part be reduced to order, and brought directly within the grasp of scientific machinery." Such a declaration would seem to be as much a defence of economics as Arbeit Macht Frei was a defence of liberty ; and it might even be supposed that Marshall in 1885 was as sceptical concerning the scientific pretensions of economics as had been Sir Francis Galton (and he was not alone in this) when in 1877 he proposed the abandonment of the economics contribution to the British Association for the Advancement of Science.' Yet there are grades and degrees of scepticism; and Marshall's cautious questioning never led him so far along the road to agnosticism as to challenge the status of his

discipline. Simply, Marshall stressed that the economist should not confuse the self-confidence of theory with the muddiness of practice, nor forget how little we know or can know about economic phenomena. That caveat out of the way, however, Marshall was only too happy to theorise about demand and supply. In our previous chapter we considered his views on demand and in this chapter we must turn to his theory of supply.