Hempel and Giere contend that the existence of provisos poses grave difficulties for any regularity account of physical law. However, Hempel and Giere rely upon a mistaken conception of the way in which statements acquire their content. By correcting this mistake, I remove the problem Hempel and Giere identify but reveal a different problem that provisos pose for a regularity account — indeed, for any account of physical law according to which the state of affairs described by a law-statement presupposes (...) a Humean regularity. These considerations suggest a normative analysis of law-statements. On this view, law-statements are not distinguished from accidental generalizations by the kind of Humean regularities they describe because a law-statement need not describe any Humean regularity. Rather, a law-statement says that in certain contexts, one ought to regard the assertion of a given type of claim, if made with justification, as a proper way to justify a claim of a certain other kind. (shrink)

Normic Laws and the Significance of Nonmonotonic Reasoning for Philosophy of Science. Normic laws have the form ‘if A then normally B’. They have been discovered in the explanation debate, but were considered as empirically vacuous (§1). I argue that the prototypical (or ideal) normality of normic laws implies statistical normality (§2), whence normic laws have empirical content. In §3–4 I explain why reasoning from normic laws is nonmonotonic, and why the understanding of the individual case is so important here. (...) After sketching some foundations of nonmonotonic reasoning as developed by AI-researchers (§5), Iargue that normic laws are also the best way to understand ceteris paribus laws (§6). §7 deals with the difference between physical and non-physical disciplines and §9 with the difference between normicity and approximation. In §8 it is shown how nonmonotonic reasoning provides a new understanding of the protection of theories against falsification by auxiliary hypotheses. §10, finally, gives a system- and evolution-theoretical explanation of the deeper reason for the omnipresence of normic laws in practice and science, and forthe connection between ideal and statistical normality. (shrink)

Gerhard Schurz [2001, Journal for General Philosophy of Science, 32, 65-107] has proposed to reconstruct auxiliary hypothesis addition, e.g., postulation of Neptune to immunize Newtonian mechanics, with concepts from non-monotonous inference to avoid the retention of false predictions that are among the consequence-set of the deductive model. However, the non-monotonous reconstruction retains the observational premise that is indeed rejected in the deductive model. Hence, his proposal fails to do justice to Lakatos' core-belt model, therefore fails to meet what Schurz coined (...) "Lakatos' challenge". It is argued that Lakatos's distinction between core and belt of a research program is not mapable onto premise-set and consequence-set and that Schurz's understanding of a ceteris paribus clause as a transfinite list of interfering factors is problematic. I propose a simple reading of Lakatos's use of the term ceteris paribus clause and motivate why the term hypothesis addition, despite not being interpretable literally, came to be entrenched. (shrink)

Summary Canfield and Lehrer argued in [1] that it is impossible to predict an event deductively from given laws and initial conditions. In [2] I showed (1) that there are counterexamples to C&L's claim, (2) that their argument was based on an assumption which they failed to recognize, let alone support (the assumption that there are ‘rejectible’ facts), (3) that if certain simple conditions on predictability were granted, it could be shown that C&L's tacit assumption is false. In a recent (...) issue of this Journal Dr. Harnatt has criticized (3) (ignoring (1) and (2)), and he has concluded that we should still wonder whether there are any deductive predictions. Dr. Harnatt's arguments are shown to be defective. (shrink)