French logician and philosopher, younger brother of Abbé de Mably. He was the main French contributor to the British empiricist philosophical tradition of Locke, Berkeley and Hume. Refusing Locke's distinction between sensations (from outer sense) and reflection (from inner sense), Condillac (1754) argued that external impressions through the outer senses can account for all ideas and all mental operations.
Condillac's main economic work (1776) was remarkably prescient in his conception of interacting markets and competition. Following up on Galiani, he developed a utility-cum-scarcity theory of value that anticipates the Marginalist Revolution by a century. For Condillac, value depends on the utility of a commodity in relation to the subjective needs of those who use it, increasing or decreasing as these needs become more or less intense. Condillac connected these variations with the degree of scarcity. In his words:
"Value is not an attribute of matter, but represents our sense of its usefulness and this utility is relative to our need. It grows or diminishes according as our need expands or contracts. But since the value of things is based upon need, it is natural that a more keenly felt need should endow things with a greater value, while a less urgent need endows them with less. Value increases with scarcity and diminishes with plenty." (Condillac, 1776: Ch. I, Pt.1)
Condillac's theories -- in economics, philosophy and psychology -- were taken up by Destutt de Tracy and (less faithfully) by Jean-Baptiste Say.
Major Works of Etienne Bonnot de Condillac
Resources on Etienne de Condillac