The structure of the Lorentz transformation depends intimately on the conventional operations for measurement of lengths (L) and time intervals (T). The prescription for length measurement leads to justifiable utilization of Euclidean geometry over finite values of the coordinates. Then T-values can be regarded as ratios of length measurements within a suitably defined clock. In certain cases the synchronization process should be supplemented by measurements providing position certification. The Lorentz transformation emerges from three specific symmetry statements, assured by the nature (...) of the L and T operations: (1) one-one correspondence of finite values of the coordinates of two inertial frames, (2) frame reciprocity, and (3) spatial isotropy. (Light signaling is not needed in this derivation. Afterward, it is assumed that light is indeed an agent moving with the common speed revealed by the transformation.) When rest masses have been determined in the conventional fashion, the conservation of momentum and of energy follow from the kinematics—a result due to Einstein. (shrink)

This work examines the nature of what philosophers call de re mental attitudes, paying close attention to the controversies over the nature of these and allied...

Le positivisme, de Comte à Carnap, a marqué une étape dans le développement d’une science spéciale en dehors des sujets traités jusque là par la philosophie. Cette communication montre que la « syntaxe logique » de Carnap comme la « synthèse subjective » de Comte est un hybride, — une tranche de la philosophie en train de devenir science, et essayant, à l’étape intermédiaire de son processus, d’être à la fois science et philosophie.