Online research in philosophy

Jarrett Leplin in A Novel Defense of Scientific Realism (1997) argues that if the thesis of empirical equivalence is cogent, then the thesis of underdetermination cannot even get off the ground. Part of Leplin's argument rests on the claim that auxiliary hypotheses can be independently confirmed, thus enabling us to determine the epistemic worth of a theory. This, in turn, helps in determining about what we should be realists. Leplin's claims are demonstrated to be problematic. Leplin wants, inconsistently, to use only those auxiliary hypotheses which dovetail with confirmed theories. Finally, a detail of Leplin's argument is found wanting.

One typical realist response to the argument from underdetermination of theories by evidence is an appeal to epistemic criteria besides the empirical evidence to argue that, while scientific theories might be empirically equivalent, they are not epistemically equivalent. In this article, I spell out a new and reformulated version of the underdetermination argument that takes such criteria into account. I explain the notion of epistemic equivalence which this new argument appeals to, and argue that epistemic equivalence can be achieved in several, significantly different, ways. On the basis of this ‘multiple realisability’ of epistemic equivalence, I then proceed to explain and examine some of the main consequences of this reformulated underdetermination argument for both realists and anti-realists.

Underdetermination is a relation between evidence and theory. More accurately, it is a relation between the propositions that express the (relevant) evidence and the propositions that constitute the theory. Evidence is said to underdetermine theory. This may mean two things. First, the evidence cannot prove the truth of the theory. Second, the evidence cannot render the theory probable. Let’s call the first deductive underdetermination, and the second inductive (or ampliative) underdetermination. Both kinds of claim are supposed to have a certain epistemic implication, viz., that belief in theory is never warranted by the evidence. This is the underdetermination thesis.

Advocates have sought to prove that underdetermination obtains because all theories have empirical equivalents. But algorithms for generating empirical equivalents simply exchange underdetermination for familiar philosophical chestnuts, while the few convincing examples of empirical equivalents will not support the desired sweeping conclusions. Nonetheless, underdetermination does not depend on empirical equivalents: our warrant for current theories is equally undermined by presently unconceived alternatives as well-confirmed merely by the existing evidence, so long as this transient predicament recurs for each theory and body of evidence we consider. The historical record supports the claim that this recurrent, transient underdetermination predicament is our own.

After a thorough examination of the claim that "the underdetermination of theory by evidence forces us to seek sociological explanations of scientists' cognitive choices", Samir Okasha concludes that the only significant problem with this argument is that the thesis of underdetermination is not adequately supported. Against Okasha, I argue (1) that there is a very good reason to question the inference from the underdetermination of a theory to a sociological account of that theory's acceptance, and (2) that Okasha's own objection to the argument is too weak.

This paper compares two kinds of epistemic principles-an underdetermination principle and a deductive closure principle. It argues that each principle provides the basis for an independently motivated skeptical argument. It examines the logical relations between the premises of the two kinds of skeptical argument and concludes that the deductive closure argument cannot be refuted without refuting the underdetermination argument. The underdetermination argument, however, can be refuted without refuting the deductive closure argument. In this respect, the deductive closure argument is the stronger of the two.

This paper compares two kinds of epistemic principles-an underdetermination principle and a deductive closure principle. It argues that each principle provides the basis for an independently motivated skeptical argument. It examines the logical relations between the premises of the two kinds of skeptical argument and concludes that the deductive closure argument cannot be refuted without refuting the underdetermination argument. The underdetermination argument, however, can be refuted without refuting the deductive closure argument. In this respect, the deductive closure argument is the stronger of the two.

The antirealist argument from the underdetermination of theories by data relies on the premise that the empirical content of a theory is the only determinant of its belief-worthiness (premise NN). Several authors have claimed that the antirealist cannot endorse NN, on pain of internal inconsistency. I concede this point. Nevertheless, this refutation of the underdetermination argument fails because there are weaker substitutes for NN that will serve just as well as a premise to the argument. On the other hand, antirealists have not made a convincing casefor NN (or its weaker substitutes) either. In particular, I criticize van Fraassen's recent claim that all ampliative rules in epistemology must be rejected on the grounds that they lead to incoherence. The status of the underdetermination argument remains unsettled.

I examine the argument that scientific theories are typically 'underdetermined' by the data, an argument which has often been used to combat scientific realism. I deal with two objections to the underdetermination argument: (i) that the argument conflicts with the holistic nature of confirmation, and (ii) that the argument rests on an untenable theory/data dualism. I discuss possible responses to both objections, and argue that in both cases the proponent of underdetermination can respond in ways which are individually plausible, but that the best response to the first objection conflicts with the best response to the second. Consequently underdetermination poses less of a problem for scientific realism than has often been thought.

Advocates of the "strong programme" in the sociology of knowledge have argued that, because scientific theories are "underdetermined" by data, sociological factors must be invoked to explain why scientists believe the theories they do. I examine this argument, and the responses to it by J.R. Brown (1989) and L. Laudan (1996). I distinguish between a number of different versions of the underdetermination thesis, some trivial, some substantive. I show that Brown's and Laudan's attempts to refute the sociologists' argument fail. Nonetheless, the sociologists' argument falls to a different criticism, for the version of the underdetermination thesis that the argument requires, has not been shown to be true.