Say's Law

In economics, Say’s Law or Say’s Law of Markets is a principle attributed to French businessman and economist Jean-Baptiste Say (1767-1832) stating that there can be no demand without supply. A central element of Say's Law is that recession does not occur because of failure in demand or lack of money. The more goods (for which there is demand) that are produced, the more those goods (supply) can constitute a demand for other goods. For this reason, prosperity should be increased by stimulating production, not consumption. In Say's view, creation of more money simply results in inflation; more money demanding the same quantity of goods does not represent an increase in real demand.
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see theory of.