This paper offers a refutation of P. Duhem's thesis that the falsifiability of an isolated empirical hypothesis H as an explanans is unavoidably inconclusive. Its central contentions are the following: 1. No general features of the logic of falsifiability can assure, for every isolated empirical hypothesis H and independently of the domain to which it pertains, that H can always be preserved as an explanans of any empirical findings O whatever by some modification of the auxiliary assumptions A in conjunction (...) with which H functions as an explanans. For Duhem cannot guarantee on any general logical grounds the deducibility of O from an explanans constituted by the conjunction of H and some revised non-trivial version R of A: the existence of the required set R of collateral assumptions must be demonstrated for each particular case. 2. The categorical form of the Duhemian thesis is not only a non-sequitur but actually false. This is shown by adducing the testing of physical geometry as a counterexample to Duhem in the form of a rebuttal to A. Einstein's geometrical articulation of Duhem's thesis. 3. The possibility of a quasi a priori choice of a physical geometry in the sense of Duhem must be clearly distinguished from the feasibility of a conventional adoption of such a geometry in the sense of H. Poincare. And the legitimacy of the latter cannot be invoked to save the Duhemian thesis from refutation by the foregoing considerations. (shrink)

Normative naturalism is a view about the status of epistemology and philosophy of science; it is a meta-epistemology. It maintains that epistemology can both discharge its traditional normative role and nonetheless claim a sensitivity to empirical evidence. The first sections of this essay set out the central tenets of normative naturalism, both in its epistemic and its axiological dimensions; later sections respond to criticisms of that species of naturalism from Gerald Doppelt, Jarrett Leplin and Alex Rosenberg.

The distinction between discovery and justification is ambiguous. This obscures the debate over a logic of discovery. For the debate presupposes the distinction. Real discoveries are well established. What is well established is justified. The proper distinctions are three: initial thinking, plausibility, and acceptability. Logic is not essential to initial thinking. We do not need good supporting reasons to initially think of an hypothesis. Initial thoughts need be neither plausible nor acceptable. Logic is essential, as Hanson noted, to both plausibility (...) and acceptability. An hypothesis needs good supporting reasons to be either plausible or acceptable. Such reasons need not be relative to the particular scientific theory undergoing test at the time. There is no fundamental difference between reasons relevant to plausibility and acceptability. The difference is one of degree. Acceptability requires more than plausibility. (shrink)

The intention of the present essay is to urge a reconsideration of the Realism-Phenomenalism-Issue, mainly and primarily in regard to the interpretation of scientific hypotheses; secondarily also relating to the basic problems of epistemology.

One of the arguments advanced in favor of scientific realism is the 'miracle argument'. It says that for the anti-realist the predictive success of science appears as an utter miracle. This argument indeed has some prima facie plausibility, provided that it is sharpened by construing "predictive success" as prediction of previously unknown laws and the occurrence of a consilience of inductions. Still, the history of science teaches us that it is possible to arrive at predictive success in this sense by (...) employing radically non-referring theoretical mechanisms. The 'miracle argument' is thus unsound. Rather, the capacity of a theory to generate predictive success can be traced back to its "classificativity correspondence.". (shrink)

In this article I discuss the justification of scientific change and argue that it rests on different sorts of invariance. Against this background I consider notions of observation, meaning, and regulative standards. I sketch an account of the rationale of scientific change which preserves the merits and avoids the shortcomings of the approach of Feyerabend, Hanson, Kuhn, Toulmin, and others. Each of these writers would hold that transitions from one scientific tradition to another force radical changes in what is observed, (...) in the meanings of the terms employed, and in the metastandards involved. They would claim that "incommensurable" replacement is what does, and should, occur during scientific "revolutions." Such writers, however, have trouble in comparing different scientific theories. My account permits different theories to be compared in various ways. These comparisons, I argue, are possible through appeal to "first-level" and "second-level" invariance. In this connection I argue that observation, meaning, and regulative standards should be, and in fact usually are, nontrivially invariant with respect to scientific change. (shrink)