Muqaddimah empires to collapse, with the result that lower revenue was collected from high rates." He wrote: Ibn Khaldun introduced the concept now popularly known as the Laffer curve, that increases in tax rates initially increase tax revenues, but eventually the increases in tax rates cause a decrease in tax revenues. This occurs as too high a tax rate discourages producers in the economy. Ibn Khaldun used a dialectic approach to describe the sociological implications of tax choice (which now forms a part of economics theory): This analysis is very similar to the modern economic concept known as the Laffer curve.
To each according to his contribution concept also formed the basic definition of socialism for its pre-Marxist proponents, including Ricardian socialists, classical economists, and individualist anarchists. "To each according to his contribution" was a concept espoused by many members of the socialist and labor movement. Examples of this can be found from Ferdinand Lassalle's and Eugen Dühring's statements to Leon Trotsky's writings. However, it was Vladimir Lenin, inspired by Marx's writing on the subject in his "Critique of the Gotha Programme", who claimed the principle to be a fundamental element of socialism within Marxist theory. Libertarian socialist thinkers, such as American anarchist Benjamin Tucker, defined socialism