Three uses of critical thought experiments outlined in the paper are related to general questions of evaluation. A proposal offered by Karl Popper concerning the so-called "apologetic" use of Gedankenexperimente is critically assessed. Specifically, his methodological principle that one should not use a second theory in order to defend a first theory against a critical thought experiment is discussed with reference to the photon-box Gedankenexperiment and the Maxwell-demon paradox. It is argued that the rescuing of one theory from conceptual anomaly (...) by appealing to another need not constitute a misuse of a critical thought experiment. (shrink)

A drastic resolution of the quantum paradoxes is proposed, combining (I) von Neumann's postulate that collapse of the state vector is due to the act of observation, and (II) my reinterpretation of von Neumann's quantal irreversibility as an equivalence between wave retardation and entropy increase, both being “factlike” rather than “lawlike” (Mehlberg). This entails a coupling of the two de jure symmetries between (I) retarded and (II) advanced waves, and between Aristotle's information as (I) learning and (II) willing awareness. Symmetric (...) acceptance of cognizance as a source of retarted waves, and of will as a sink of advanced waves, is submitted as a central “paradox” of the Copernican or Einsteinian sort, out of which new light is shed upon previously known paradoxes, such as the EPR paradox, Schrödinger's cat, and Wigner's friend. Parapsychology is thus found to creep into the picture. (shrink)

Once upon a time the well-known paradoxes of quantum mechanics seemed especially difficult because of the rather bizarre behavior of the wave packet under the von Neumann theory of measurement, to which behavior these paradoxical situations seemed to draw especial attention. Quite recently quantum theoretical accounts of the measurement process have been appearing which sidestep direct reference to such things as “contraction” of the wave packet. With this development it has become increasingly popular to take a “cool” approach to these (...) paradoxes, arguing that the new approach to measurement provides a consistent, nonbizarre account of the physical situations and that the paradoxicality was due largely to intuitive blunders—even plausible intuitive blunders—accentuated by the unfortunate features of the von Neumann approach to measurement. Both Krips and Jauch, for example, adopt this approach. (shrink)

Contrary to the Empiricist model of science, successful sufficiently fundamental theories not only fit and unify their data fields but also prescribe the general terms in which relevantly to describe observation; specify what is and is not observable; specify the conditions under which what is observable, is observable; specify the instrumental means and reliability by which what is measurable is measured; specify what is causally, statistically, and merely accidentally connected. Moreover, such theories typically require all or most of the entire (...) remainder of science to be properly applied in any given situation and theoreticians' models play a crucial role in such applications. (I call these respectively the internal and external globalnesses of theories.) A discussion of the consequences of these global features of theories for philosophy of science is offered in the context of specific examples and a structural model for science. (shrink)