Classical economists did not deny the possibility of shortlived periods of economic difficulty characterised by unsold commodities, idle capital and redundant labour. Even James Mill, ever prone to outbursts of intellectual frustration with those who failed to grasp the tautological nature of his formulation of Say's Law, accepted the possibility of partial gluts. Yet for Mill, the overproduction of one commodity implied the underproduction of another. A surfeit of capital and labour applied to the production of one good necessarily entailed a deficiency of capital and labour in some other productive sphere: ‘It is … impossible, that there should be in any country a commodity or commodities in quantity greater than the demand, without there being to an equal amount, some other commodity or commodities in quantity less than demand.’ Such partial gluts must, therefore, be temporary phenomena disappearing when the movement of capital and labour reoriented the nation's productive base to match the prevailing structure of demand.

Ricardo also accepted the existence of temporary economic disequilibria when, for example, the too rapid accumulation of fixed capital produced a redundancy of labour.