The paradox of thrift (or paradox of saving) is a paradox of economics, popularized by John Maynard Keynes, though it had been stated as early as 1714 in The Fable of the Bees,<1> and similar sentiments date to antiquity.<2> The paradox states that if everyone tries to save more money during times of recession, then aggregate demand will fall and will in turn lower total savings in the population because of the decrease in consumption and economic growth. The paradox is, narrowly speaking, that total savings may fall even when individual savings attempt to rise, and, broadly speaking, that increases in savings may be harmful to an economy.<3> Both the narrow and broad claims are paradoxical within the assumption underlying the fallacy of composition, namely that what is true of the parts must be true of the whole. The narrow claim transparently contradicts this assumption, and the broad one does so by implication, because while individual thrift is generally averred to be good for the economy, the paradox of thrift holds that collective thrift may be bad for the economy.
http://en.wikipedia.org/wiki/Paradox_of_thrift