I just re-read Will Baumol’s Welfare Economics and the Theory of the State, first published in 1952, based on his doctoral dissertation, with a 2nd edition in 1965. I started mulling over welfare economics while writing my latest book, Markets, State and People: Economics for Public Policy (OUT THIS WEEK – TA-DAH!).

This is the area of economics concerned with the question of what it means for society to be better off. As a branch of theory, welfare economics is highly abstract and mathematical, covering the existence of a general equilibrium, its optimality properties (and the extent to which these are delivered by the market economy), and the various impossibility theorems about aggregating individual utlities into social welfare. As a matter of practice, some hazy sense of all of this theory lies behind policies such as the use of cost-benefit analysis. In writing the book, I became increasingly and uncomfortably aware of the theory-practice gap.

Better economists than me were on to this earlier. In 2001 the late, great Tony Atkinson wrote a powerful article noting the ‘strange disappearance of welfare economics’, largely ignored since the 1970s – it was published in a journal (*Kyklos*) unknown to many economists unfortunately. As it turns out, Baumol skewered the basic problem in this book. “Mathematical manipulation can yield no more than is contained in the premises which are being examined. Walras [in his work on general equilibrium], by assuming that every indivudal independently sought his own ends, obtained mathematical statements which amounted to the not excessively surprising assertion that every individual did as well for himself as possible under the circumstances.”

In other words, if you assume individuals are wholly independent, you conclude that the optimal economic organisation simply requires individual decision-making. But as Baumol points out in the final chapter, titled The Wreck of Welfare Economics, any brush with empirical reality underlines the interdependence of both production and consumption decisions. His conclusion: if economics is to say anything of practical use about economic progress, we need to start filling – with both theory and empirics – the currently empty boxes with labels like ‘externalities’ and ‘increasing returns’.