Adam Smith's ideas in The Wealth of Nations influenced the development of capitalism during the Industrial Revolution. He believed in free markets and that economic liberty guaranteed progress. Competition forces businesses to make better products at lower prices according to the laws of self-interest, supply and demand, and competition. Thomas Malthus and David Ricardo built on Smith's ideas and opposed government assistance to workers. Under capitalism, private individuals and businesses own property and means of production, and progress results from self-interest and competition between businesses. This system replaced feudalism and helped bring about the Industrial Revolution through investment, increased production, trade, transportation innovations, and changes in industries.