How did Adam Smith explain the relationship between higher wages and the supply of workers?

In The Wealth of Nations, Adam Smith did not propose a single, definitive theory regarding the relationship between wages and the supply of workers, though he anticipated several concepts later developed by other economists.1

Smith generally viewed wages as being determined by the market through the law of supply and demand. He observed that in an advancing economy, wage levels would need to rise above the subsistence level to encourage population growth, as a larger workforce would be required to fill the additional jobs created by economic expansion.1

Furthermore, elements of his thought contributed to the subsistence theory, which suggests that if wages rise above the level necessary for basic needs, the number of workers might increase, subsequently exerting downward pressure on wage rates. Smith also emphasized that workers must be compensated with higher wages to offset the costs associated with acquiring new skills, an idea that prefigures modern human-capital theory. Ultimately, Smith believed that the competitive pursuit of self-interest by both employers and workers would naturally guide labor toward areas of greatest need.213