Was born in Jerusalem in 1935.
In 1958 his obtained his B.A. degree in economics and philosophy from the Hebrew University of Jerusalem, and in 1962 he was awarded a Ph.D. in economics and statistics at Stanford University. He served as professor of economics at Yale University for five years and after his return to Israel in 1967 he was appointed professor at the Department of Economics of the Hebrew University.
Over the years he held visiting appointments at many universities around the world. His studies examined the principles of economic theory and contributed to the understanding of the connection between economics, philosophy, and psychology. In his works, some of them on the subject of distributive justice, he indicated how economic theory relates to analytical philosophy. His view is that the link between economic theory and reality is sometimes similar to the link between philosophical debate and reality.
His 1965 work about choosing a consumption and life insurance plan for a consumer who deals with survival uncertainty has solved a basic and extremely intricate problem of its time. Even today this work is considered important for understanding economic growth rates as a consequence of policy. In the 1980s he examined a problem linked to the von Neumann-Morgenstern Expected Utility Hypothesis. He proposed an alternative theory which is in keeping with the findings of psychological research and yet provides explanations for questions regarding the individual’s behavior under conditions of uncertainty.
In 1991 he initiated and helped found the Center for the Study of Rationality at the Hebrew University and served as chair of the Center’s Academic Committee until 2004.
Between 1992 and 1997 he was the president of the Open University of Israel. He was also a founding member of the Israeli-Palestinian Science Organization (IPSO).
In 2004 he was elected president of the Israel Academy of Sciences and Humanities, a position he held until 2010. His work won him many prizes, among them the Israel Prize for Economics (1987) and the Rothschild Prize in Social Sciences (1994). He is a foreign member of the American Academy of Arts and Sciences, the American Philosophical Society, the Berlin-Brandenburg Academy of Sciences and.Humanities and a foreign honorary member of the American Economic Association.