The theory of economic liberalism emerged in the context of the end of mercantilism, a period in which it was necessary to establish new paradigms, as capitalism was increasingly taking root. The central idea of economic liberalism is the defense of the economy's emancipation from any dogma external to itself, that is, the elimination of interference from any means in the economy.
Such theory emerged at the end of the 18th century, with François Quesnay as one of its main theorists. Quesnay claimed that the real productive activity was embedded in agriculture. Another thinker who contributed to the development of the theory of economic liberalism was Vincent de Gournay, who said that the commercial and industrial activities should enjoy freedom, to develop and achieve the accumulation of capitals.
However, the main theorist and father of the theory of economic liberalism was Adam Smith. The Scottish economist confronted the ideas of Quesnay and Gournay, stating in his book “The Wealth of Nations” the main ideas of economic liberalism: prosperity economic and wealth accumulation are not conceived through rural or commercial activity, but through free labor, without any regulatory or intervener.
For Smith, interventions in the economy were not necessary, since the market itself had its own mechanisms for regulating the the same: the so-called “invisible hand”, which would be responsible for bringing benefits to the entire society, in addition to promoting evolution widespread. Liberalists defend free competition and the law of supply and demand. These theorists were the first to treat economics as a science.
Source: Brazil School - https://brasilescola.uol.com.br/economia/liberalismo-economico.htm