Action (physics)

Abstract: An action principle technique for the direct computation of expectation values is described and illustrated in detail by a special physical example, the effect on an oscillator of another physical system. This simple problem has the advantage of combining immediate physical applicability (e.g., resistive damping or maser amplification of a single electromagnetic cavity mode) with a significant idealization of the complex problems encountered in many‐particle and relativistic fieldtheory. Successive sections contain discussions of the oscillator subjected to external forces, the oscillator loosely coupled to the external system, an improved treatment of this problem and, finally, there is a brief account of a general formulation.

Abstract: Abstract Alfred Gell puts forward a new anthropological theory of visual art, seen as a form of instrumental action: the making of things as a means of influencing the thoughts and actions of others. He argues that existing anthropological and aesthetic theories take an overwhelmingly passive point of view, and questions the criteria that accord art status only to a certain class of objects and not to others. The anthropology of art is here reformulated as the anthropology of a category of action: Gell shows how art objects embody complex intentionalities and mediate social agency. He explores the psychology of patterns and perceptions, art and personhood, the control of knowledge, and the interpretation of meaning, drawing upon a diversity of artistic traditions--European, Indian, Polynesian, Melanesian, and Australian. Art and Agency was completed just before Alfred Gell's death at the age of 51 in January 1997. It embodies the intellectual bravura, lively wit, vigour, and erudition for which he was admired, and will stand as an enduring testament to one of the most gifted anthropologists of his generation.