Indifference curve

A diagram depicting equal levels of utility (satisfaction) for a consumer faced with various combinations of goods. Or Indifference curve is a graph showing different bundles of goods between which a consumer is indifferent. That is, at each point on the curve, the consumer has no preference for one bundle over another. One can equivalently refer to each point on the indifference curve as rendering the same level of utility (satisfaction) for the consumer. Utility is then a device to represent preferences rather than something from which preferences come.

The main use of indifference curves is in the representation of potentially observable demand patterns for individual consumers over commodity bundles. There are infinitely many indifference curves: one passes through each combination. A collection of (selected) indifference curves, illustrated graphically, is referred to as an indifference map. Or a graph of indifference curves for an individual consumer associated with different utility levels is called an indifference map. The theory of indifference curves was developed by Francis Ysidro Edgeworth, who explained in his book "Mathematical Psychics: an Essay on the Application of Mathematics to the Moral Sciences”, 1881.