What economic principle means "all other things being equal" when analyzing determinants?

The economic principle that translates to "all other things being equal" is known as Ceteris Paribus. This Latin phrase is fundamental in economic analysis as it allows economists to isolate the effect of one variable while assuming that other relevant factors remain unchanged.

For instance, when examining the relationship between the price of a good and the quantity demanded, Ceteris Paribus permits the analysis to focus solely on price changes, without the complication of other variables like consumer preferences or income levels affecting demand simultaneously. This simplification ensures a clearer understanding of the direct effects of a specific change, which is crucial in economic modeling and theory.

In contrast, the other options do not encompass this principle. Market equilibrium pertains to a state where supply equals demand and does not inherently involve the notion of holding other variables constant. Opportunity cost refers to the value of the next best alternative foregone when a decision is made, addressing trade-offs rather than isolating variables. Marginal utility relates to the additional satisfaction or benefit derived from consuming one more unit of a good, which also does not reflect the concept of controlling for other factors.