How is it that people working in their own self- intrest produce goods services and wealth for others?

People working in their own self-interest contribute to the production of goods, services, and wealth for others through the mechanism of the market. When individuals pursue their own goals, such as profit or personal satisfaction, they are incentivized to create products or services that others want or need. This drive for self-gain fosters competition and innovation, leading to better quality and lower prices, ultimately benefiting consumers. In this way, self-interest aligns with the collective welfare, as it stimulates economic growth and improves overall living standards.