Marx presents two theories about employment contracts: one views it as a trade of labor for money, the other sees it as a way for capitalists to control workers. In the first theory, workers sell their ability to work for a wage, which leads to exploitation. The second theory sees the contract as a tool for capitalists to dominate workers in the production process. Marx's ideas were influenced by Saint-Simon and Hegel, and he believed that exploitation stems from power imbalances between workers and capitalists.