부산대학교 도서관

Hicks, in his delineation of substitutes based on the sign of the substitution term, established a definition that has been widely employed in discerning the relationship between two goods due to its intuitive and easily explicable nature. Samuelson in his paper, however, demonstrated that the relationship between two goods becomes less perspicuous when another good is concurrently consumed as both a substitute and a complement. In a more comprehensive context, substitution can be conceptualized as the process by which one good is replaced to achieve specific objectives. When applied to Hicks' definition of substitution, it suggests that a good is replaced by another good with a relatively lower price for utility. In this context, the price assumes the role of a mediating variable. By modifying the mediating variable, it becomes conceivable to redefine substitutes in alternative ways. This study suggests that income and physical constraints also serve as pertinent mediating variables. Consequently, the concept of substitutes can be extended beyond those contingent on price to encompass substitutes contingent on income and substitutes contingent on constraint. The integration of these new types of substitute categories into economic theory has the potential to yield alternative theoretical narratives.