it is regularly made, the effect of it is, that the supply for the most part is found to be in proportion to it, and then the demand is simple". It is presumably from this chapter that the idea spread to other authors and economic thinkers. Adam Smith used the phrase after Steuart in his 1776 book The Wealth of Nations. In The Wealth of Nations, Smith asserted that the supply price was fixed but that its "merit" (value) would decrease as its "scarcity" increased, this idea by Smith was later named the law of demand. In 1803, Thomas Robert Malthus used the phrase "supply and demand" twenty times in the second edition of the Essay on Population. And David Ricardo in his 1817 work, Principles of Political Economy and Taxation, titled one chapter, "On the Influence of Demand and Supply on Price". In Principles of Political Economy and Taxation, Ricardo more rigorously laid down the idea of the assumptions that were used to build his ideas of supply and demand. In 1838, Antoine Augustin Cournot developed a mathematical model of supply and demand in his Researches into the Mathematical Principles of Wealth, it included diagrams. It is important to note that the use of the phrase was still rare and only a few examples of more than 20 uses in a single work have been identified by the end of the second decade of the 19th century. During the late 19th century the marginalist school of thought emerged. The main innovators of this approach were Stanley Jevons, Carl Menger, and Léon Walras. The key idea was that the price was set by the subjective value of a good at the margin. This was a substantial change from Adam Smith's thoughts on determining the supply price. In his 1870 essay "On the Graphical Representation of Supply and Demand", Fleeming Jenkin in the course of "introduc[ing] the diagrammatic method into the English economic literature" published the first drawing of supply and demand curves in English, including comparative statics from a shift of supply or demand and application to the labor market. The model was further developed and popularized by Alfred Marshall in the 1890 textbook Principles of Economics. Criticism The philosopher Hans Albert has argued that the ceteris paribus conditions of the marginalist theory rendered the theory itself an empty tautology and completely closed to experimental testing. In essence, he argues,