Hedonic calculus refers to the philosophical theory of calculating pleasure and pain. There are different synonyms for hedonic calculus, such as the law of diminishing returns, pleasure principle, and utility maximization. The law of diminishing returns states that the marginal utility, or pleasure, decreases as more of a good or activity is consumed. The pleasure principle pertains to the idea that people are motivated to seek pleasure and avoid pain. Lastly, utility maximization is a concept in economics that assumes people make decisions based on their perceived value or utility. All these synonyms highlight the importance of pleasure and pain in decision-making and how individuals strive to maximize their pleasure while minimizing their pain.