Final answer:
Adam Smith argued that self-interest leads to economic output and market efficiency, benefiting society as a whole through an 'invisible hand' mechanism, where personal gain drives positive societal outcomes.
Step-by-step explanation:
Adam Smith, in his seminal work The Wealth of Nations, suggested that self-interest benefits society by leading to economic growth and efficiency. When individuals act in their self-interest, they are likely to engage in work that they find rewarding and efficient, resulting in the creation of economic output. Additionally, as consumers pursue goods and services at the best possible prices, businesses are incentivized to produce what consumers want in the most efficient way possible. This interaction between producers and consumers driven by self-interest helps the economy to function fluidly and thus benefits society as a whole. Smith called this mechanism the 'invisible hand', a metaphor for the self-regulating behavior of the marketplace where individuals' pursuit of self-gain leads to societal benefits.