Pigou, a British welfare economist (meaning that his economic theories focuses on maximizing the well-being of society), studied at King's College in Cambridge and later served as the chair of political economy at Cambridge from 1908 to 1943.
Pigou is also known for his contributions to the aggregate demand-aggregate supply model (the "real balances effect"), and to theories of price discrimination.
Pigou's reasoning was that the marginal utility of a dollar for a poor man was greater than for a rich man, and so by transferring dollars from the rich to the poor, the net gain in social welfare would be positive.