The productive-unproductive puzzle in Adam Smith: what have we missed?

This paper returns to Adam Smith's much maligned distinction of productive versus unproductive labour to flesh out a dimension of capital productivity that has been missed by the modern theory of production and welfare. The puzzle lies in Smith's use of a binary measurement scale to suggest opposing productivity, and household welfare outcomes obtained with a durable versus non-durable good. A durable good generates a permanent fund of labour savings and service spillovers over time. This dimension of productivity exists separate from, and beyond, any marginal productivity attributed to capital or labour services within the neoclassical production function. And, it forms the basis of improvements in household welfare that Smith described in the Wealth of Nations – in terms of continual net increases in the consumption-production possibility frontier enjoyed by the household, as a result of service spillovers obtained with a durable good over time. In contrast, no such spillovers are obtained with a non-durable good. A preference-bias for non-durable goods, instead, proves to be welfare-reducing – by having households under-invest and/or fail in maintaining the accumulated stock of durable-goods-as-capital. Both lead to a loss of production-consumption possibilities available within the household economy. An exploration of Smith's concern with 'unproductive labour' brings back into focus the broad set of behavioural traits and ethical-legal restraints that underlie economic progress and have been missed by neoclassical theory.