The determination of the meaning of theoretical terms by the axioms of theories as meaning postulates and the merely fictitious character of a basic observational language leads to Feyerabends problem of the incommensurability of physical theories. Different theories are actually compared by physicists as well. They might have a common sublanguage as the language of macroscopic physics in atomic physics. Furthermore shared metalaws (e. g. invariance principles) define an equivalence relation which identifies terms of different theories and enables physicists to (...) talk about them in a common language. (shrink)

The following definition of “objective” is proposed: A statement S is objective if and only if in S all parameters that are relevant to its truth value are made explicit. The objectivity of predicates and relations can be defined in a similar manner. This simple conception of objectivity-which could be called “explicitness conception of objectivity”-can be found in Hermann Weyl and plays a central part in the natural sciences. There are grades of objectivity depending on the ‘quality’ and the number (...) of parameters our predicates are relativized to A relativistic Ockham principle has to be recognized: Relativization parameters are not to be multiplied beyond necessity. The explicitness conception of objectivity is accessible to mathematical specifications, is the core of the idea of invariance, has a lot of philosophical applications and leads to precise notions of ‘subjectivity’ and a precise formulation of the problem of the limits of objectivity. (shrink)

Summary Some leading ideas of the constructivist protophysics are discussed on the basis of P. Janich's Protophysik der Zeit. After having reviewed the contents of the second edition Janich's claim that analytical philosophy of science is purely affirmative and not critical towards science in its historical appearence is refuted. In the next section the principles of constructivist methodology of physics are criticised, and the claim is refuted that prescriptions for measurement cannot without circularity be shown to be invalid by experimental (...) results. In the last section we discuss Janich's foundation of time measurement in a mathematical frame similar to that for extensive systems. Thus the relation between Janich's and the ordinary account is cleared up. (shrink)

The determination of the meaning of theoretical terms by the axioms of theories as meaning postulates and the merely fictitious character of a basic observational language leads to Feyerabends problem of the incommensurability of physical theories. Different theories are actually compared by physicists as well. They might have a common sub-language as the language of macroscopic physics in atomic physics. Furthermore shared metalaws define an equivalence relation which identifies terms of different theories and enables physicists to talk about them in (...) a common language. (shrink)