The paradox of thrift (or paradox of saving) is a paradox of economics. The paradox states that an increase in autonomous saving leads to a decrease in aggregate demand and thus a decrease in gross output which will in turn lower total saving. The paradox is, narrowly speaking, that total saving may fall because of individuals' attempts to increase their saving, and, broadly speaking, that increase in saving may be harmful to an economy. The paradox of thrift is an example of the fallacy of composition, the idea that what is true of the parts must always be true of the whole. The narrow claim transparently contradicts the fallacy, and the broad one does so by implication, because while individual thrift is generally averred to be good for the individual, the paradox of thrift holds that collective thrift may be bad for the economy.
It had been stated as early as 1714 in The Fable of the Bees, and similar sentiments date to antiquity. It was popularized by John Maynard Keynes and is a central component of Keynesian economics.
The paradox
The argument begins from the observation that in equilibrium, total income must equal total output. Assuming that income has a direct effect on saving, an increase in the autonomous component of saving, other things being equal, will move the equilibrium point at which income equals output to a lower value, thereby inducing a decline in saving that may more than offset the original increase.
In this form it represents a prisoner's dilemma as saving is beneficial to each individual but deleterious to the general population. This is a "paradox" because it runs contrary to intuition. Someone unaware of the paradox of thrift would fall into a fallacy of composition and assume that what seems to be good for an individual within the economy will be good for the entire population. However, exercising thrift may be good for an individual by enabling that individual to save for a "rainy day", and yet not be good for the economy as a whole.
This paradox can be explained by analyzing the place, and impact, of increased savings in an economy. If a population decides to save more money at all income levels, then total revenues for companies will decline. This decreased demand causes a contraction of output, giving employers and employees lower income. Eventually the population's total saving will have remained the same or even declined because of lower incomes and a weaker economy. This paradox is based on the proposition, put forth in Keynesian economics, that many economic downturns are demand-based.
History
While the paradox of thrift was popularized by Keynes, and is often attributed to him, it was stated by a number of others prior to Keynes, and the proposition that spending may help and saving may hurt an economy dates to antiquity; similar sentiments occur in the Bible verse:
which has found occasional use as an epigram in underconsumptionist writings.
Keynes himself notes the appearance of the paradox in The Fable of the Bees: or, Private Vices, Publick Benefits (1714) by Bernard Mandeville, the title itself hinting at the paradox, and Keynes citing the passage:
Keynes suggests Adam Smith was referring to this passage when he wrote "What is prudence in the conduct of every private family can scarce be folly in that of a great Kingdom."
The problem of underconsumption and oversaving, as they saw it, was developed by underconsumptionist economists of the 19th century, and the paradox of thrift in the strict sense that "collective attempts to save yield lower overall savings" was explicitly stated by John M. Robertson in his 1892 book The Fallacy of Saving, writing:
Similar ideas were forwarded by William Trufant Foster and Waddill Catchings in the 1920s in The Dilemma of Thrift.
Keynes distinguished between business activity/investment ("Enterprise") and savings ("Thrift") in his Treatise on Money (1930):
He stated the paradox of thrift in The General Theory, 1936:
The theory is referred to as the "paradox of thrift" in Samuelson's influential Economics of 1948, which popularized the term.
Paradox of thrift according to Balances Mechanics
The paradox of thrift formally can be well described as a circuit paradox using the terms of Balances Mechanics developed by the German economist Wolfgang Stützel (German: Saldenmechanik): It is about saving by cut of expenses, which always leads to a revenue surplus of the individual, so to saving of money. But once the totality (in the meaning of every each) saves at expenses, the revenues of economy only decline.
