On account of the impressive yield of empirical science since the dawn of modern era, theorists of human behavior have sought eagerly to adopt its methodology to explain and predict behavior in the same way that natural science does with respect to natural phenomena. Thus, the positivist principle endorsed the unity of science approach to both the natural and social worlds. Modern social science, in its specific forms of sociology, economics, and so on, confidently embraced the positivist principle. In a short period of time, political economy was transformed into economic science. The goal was to purge the social sciences of their supposedly evaluative content. In due course, the idea of objective scientific truth came to be questioned along with the positivist paradigm. Epistemological relativism à la Kuhn is to be credited with this intellectual shift. But this novel theoretical approach was more easily accommodated by epistemologists of science than scientists themselves. Scientists hardly questioned their methodologies of research and the cognitive field of successful theories. Similarly, in the social sciences, neoclassical economics remained dominant. The neoclassical motto was that economics as science answered only questions of efficiency, not evaluative questions of social justice. The Human Project and the Temptations of Science argues that the model of epistemological unity, at one time embracing positivism, at another time supporting epistemological relativism, is questionable. While empirical science does yield knowledge of the natural world, knowledge of the social world - the world of humans - is necessarily value-laden. Despite the quantitative veneer of neoclassical economics - the dominant paradigm in economics - economic analysis cannot avoid questions of value. The reason is that its foundational concepts, such as rationality and the maximization of expected utility, reflect the necessary value-oriented nature of human behavior. The question posed, then, by The Human Project and the Temptations of Science is what sort of optimal values should humans adopt.