At the core of human existence is the act of choice. With limited resources and numerous problems to solve, individuals must make value judgments and select one out of many options. Each action represents a choice and implies that an infinite number of alternative choices were sacrificed. Choice necessitates exchange, as individuals trade a current state of affairs for a future one that they believe is superior. The list of alternatives that were not pursued represents the opportunity cost of an action, or the potential future scenarios that were disregarded and left unrealized.
[[Scarcity]] [[Law of marginal utility]] [[Subjective preference scale]]