節儉悖論

解釋

圖解

• 由此得出兩條函數：
• ${\displaystyle I={\overline {I}}+iY}$
• ${\displaystyle S={\overline {S}}+sY}$

歷史

As this prudent economy, which some people call Saving, is in private families the most certain method to increase an estate, so some imagine that, whether a country be barren or fruitful, the same method if generally pursued (which they think practicable) will have the same effect upon a whole nation, and that, for example, the English might be much richer than they are, if they would be as frugal as some of their neighbours. This, I think, is an error.

Had the whole population been alike bent

on saving, the total saved would positively have been much less, inasmuch as (other tendencies remaining the same) industrial paralysis would have been reached sooner or oftener, profits would be less, interest much lower, and earnings smaller and more precarious. This ... is no idle paradox, but the strictest economic truth.

——John M. Robertson, The Fallacy of Saving, p. 131–2

……僅僅節制並不足以建立城市或枯竭沼澤。……如果企業進行中，不論節儉發生甚麼財富也會累積；如果企業停滯不前，不論節儉做了甚麼財富也會消耗。因此，節儉可以是企業的婢女。但同樣地她可以不是。甚或乎，她經常不是。
...mere abstinence is not enough by itself to build cities or drain fens. ... If Enterprise is afoot, wealth accumulates whatever may be happening to Thrift; and if Enterprise is asleep, wealth decays whatever Thrift may be doing. Thus, Thrift may be the handmaiden of Enterprise. But equally she may not. And, perhaps, even usually she is not.

For although the amount of his own saving is unlikely to have any significant influence on his own income, the reactions of the amount of his consumption on the incomes of others makes it impossible for all individuals simultaneously to save any given sums. Every such attempt to save more by reducing consumption will so affect incomes that the attempt necessarily defeats itself. It is, of course, just as impossible for the community as a whole to save less than the amount of current investment, since the attempt to do so will necessarily raise incomes to a level at which the sums which individuals choose to save add up to a figure exactly equal to the amount of investment.
——John Maynard Keynes, The General Theory of Employment, Interest and Money, Chapter 7, p. 84

參考文獻

1. ^ Keynes, 《就業、利息與貨幣的一般理論》（The General Theory of Employment, Interest and Money）, Chapter 23. Notes on Merchantilism, the Usury Laws, Stamped Money and Theories of Under-consumption
2. ^ These two formulations are given in Campbell R. McConnell (1960: 261–62), emphasis added: "By attempting to increase its rate of saving, society may create conditions under which the amount it can actually save is reduced. This phenomenon is called the paradox of thrift....[T]hrift, which has always been held in high esteem in our economy, now becomes something of a social vice."
3. ^ Hayek on the Paradox of Saving
4. ^ Pages 37-39 of http://www.mises.org/rothbard/agd.pdf
5. ^ 5.0 5.1 Nash, Robert T.; Gramm, William P. A Neglected Early Statement the Paradox of Thrift. History of Political Economy. 1969, 1 (2): 395–400. doi:10.1215/00182702-1-2-395.
6. ^