Jevons was a British economist (1835-1882), who is considered, along with Carl Menger and M.-E.-L. Walras, a co-founder of marginalism and theory of utility. Jevons is the author of the book “The Theory of Political Economy”, 1871, in which he devised the concept of marginal utility, from an additive and separable utility function, although it was not measurable on cardinal terms. These studies were possible thanks to Johann H. von Thünen’s works, who was the first economist to use the word “marginal”, which meaning Jevons adopted in his works using the term “final”. He is also considered as a precursor of Econometrics for his work on business cycle, index numbers and moving averages, topics on which he used his extensive knowledge of mathematics.

Although his works on marginal utility are considered pioneer during the marginal revolution, and important for the development of neoclassical economics, Jevons considered there would be only one possible solution when considering barter exchange. However, there are infinite solutions, as was demonstrated later on by Francis Y. Edgeworth, whose indifference curves are based on Jevons’ earlier work.

Carl Menger, was an Austrian economist (1840-1921), who is considered to be, along with W. S. Jevons and M.-E.-L. Walras, a co-founder of marginalism and of the theory of utility, and was also founder of the Austrian School, where his main followers Wieser and Böhm-Bawerk were his disciples. In his “Principles of Economics”, 1871, Menger attacked as incorrect the labor theory of value, expressing his view that the factor determining the value of a good is not the amount of work nor other goods needed to produce it, but the importance we place on the basis of the satisfaction we believe that it can offer.

Karl Marx was a German politician, philosopher, economist, and sociologist (1818-1883). He studied law and it was in his famous “Thesis on Feuerbach”, where he formulated the proposition that the philosopher must not be contented with the contemplation of life, but must contribute in changing it. Marx’s early contributions to Economics were as editor of the “Rheinische Zeitung”, whose radical content made him face Prussian authorities. In 1847, along with Friedrich Engels, he wrote the Communist Manifesto, true synthesis of his thinking. However, his most important work is “Capital: Critique of Political Economy”.

Although he is the one who gave name to the Classical school of Economics, and he might not be considered a part of it because of his different conclusions on theory of value, we consider he should be considered part of this school, mainly because he worked on the same issues as other classical authors.

Adam Smith was born in 1723. His father was a lawyer and civil servant, and during his years as a moral philosophy student at the University of Glasgow, Adam Smith developed an increasing interest in liberty, reason and free speech. He then went on to continue his studies at Oxford, where he started writing about the low quality of education in English universities. Later, he taught at Edinburgh and the University of Glasgow, where he would end up occupying the position of rector until his death, in 1790.

During his lifetime, Smith met well known philosophers such as David Hume and Voltaire and other intellectual leaders such as Benjamin Franklin, François Quesnay or A.-R.-J. Turgot, who influenced his work, helping him become the first great economist of the Classical school of economics.

“The Wealth of Nations,” which took twelve long years to write, finally published in 1776, is the foundation of modern economics. It was basically against prevailing mercantilist theories, introducing the importance of the principle of division of labour and defending free trade. Basically, Smith understood that the satisfaction of individual self-interest, limited by that of the others was the best means to achieve the greatest good for the greatest number of people. However, he supported the State’s action in justice, education, health, and in all those enterprises that private initiative was unable to address.

Ricardo, an English economist (1772-1823), from Dutch-Sephardi origins, became rich at a very young age on the stock market and devoted the rest of his life to the study of mathematics and natural sciences and, from 1799, Economics. He became known with his pamphlet “The high price of bullion” on economic issues, and ended his work with his “Principles of Political Economy and Taxation.” Ricardo took the major step in the process of deductive abstraction of what later became known as the Classical school of economics in the path initiated by Adam Smith. His theories of comparative advantage, which were firstly stated in 1815 by Col. Robert Torrents (Ricardian trade theory), rent of land (Ricardian distribution theory) and the steady state, were some of their major contributions to economic science.

Malthus was an English reverend (1766-1843), who in his book “An Essay on the Principles of Population,” wrote an argument against his contemporary Mr. Godwin, who believed in unlimited population growth. Malthusian population theory warned of the possibility, that while the population grew geometrically, food resources grew only in arithmetical proportion, thus creating the conditions for a shortage in the long term that would require an adjustment in the birth rate. This law of Malthus’s population was severely criticized by Karl Marx, another heterodox economist from the Classical school of economics, who called the parish of Albury “advocate of the bourgeoisie.” The principles of Malthus had great influence on the thinking of Darwin and Wallace about the struggle for life as the source of the natural selection of the strongest.

In his “Principles of Political Economy”, Malthus explained how he was against Say’s Law, by considering demand as an aggregate. Thus, if wages were to be mantained at a subsistence level, aggregate demand would drop. Therefore there would be a production surplus, idea that would be used by J.M. Keynes in his “The General Theory of Employment, Interest and Money”.