[[Bernard Mandeville]] first introduced this concept in his ''The Fable of the Bes'' (1714) and [[classical economists]] later picked up on it. It became a central part of [[Keynesian economics]], but now is viewed as a short-run rather than a long-run issue. | [[Bernard Mandeville]] first introduced this concept in his ''The Fable of the Bes'' (1714) and [[classical economists]] later picked up on it. It became a central part of [[Keynesian economics]], but now is viewed as a short-run rather than a long-run issue. |