Online research in philosophy

Larry Laudan has challenged the realist to come up with a program that submits realism to "those stringent empirical demands which the realist himself minimally insists on when appraising scientific theories." This paper shows how the realist can go about taking up Laudan on this challenge; and, in such a way that the realist hypothesis actually ends up being confirmed, by any empirical standards. In other words, it is shown that we can test for convergent realism, just as readily as Laudan can test for a connection between theories that are controlled by the cannons of science and their subsequent reliability.

Philosophers are drawn to the Atomic Theory like a dog to an old shoe, but my results about realism and anti-realism in Tracking Truth, and the distinctive position I have carved out on their basis, are independent of the fate of my comments about that historical case. I will defend those comments against Stanford’s objections below, but first I will explain the argument of my chapter, because its results undermine not only historically important antirealist positions, but also the approach via unconceived conceivables that Stanford’s criticisms (and his pessimistic induction) depend on. The issue is claims about equal evidential support that empiricist defenses of epistemological anti-realism, including Stanford’s, must and do appeal to. In Chapter 6 of Tracking Truth, I show that the best known probabilistic definitions of evidential support imply the anti-realist’s key equalsupport claims are either false or inconsistent with the view he wants to base on them. There are reasons to think that it is not even possible to define a probabilistic notion of support that will do the job the anti-realist needs. It follows from this, as I explain below, that the anti-realist has not defended the claim that we are in principle, or even probably, unable to confirm high-level theories – for this, I say, we must wait and see, and make our best estimates. This, and my claim that we have actually gotten beyond observables – a point made with pregnancy tests and tests for medical conditions – make room for realism. I do not endorse the kind of realist claim that says we generally have a right to believe our successful hypotheses that go beyond observables. Some successful hypotheses are better confirmed than others, and some are not at all. However, since the anti-realist’s general skeptical arguments fail, I also do not think we need such general claims in order to have a right to confidence in those particular hypotheses for which we do have good evidence. I call my approach to the epistemological realism-anti-realism debate “evidential.” The nub of the issue between the two camps has always been whether we have a right to believe our scientific theories – in some sense that includes at least some of their claims about unobservable matters – on the basis of our evidence.1 Answers to this question depend on what our evidence actually is, and on the definition or criteria for evidential support..

According to Wrights minimalism, a notion of truth neutral with respect to realism and antirealism can be built out of the notion of warranted assertibility and a set of a priori platitudes among which the Equivalence Schema has a prominent role. Wright believes that the debate about realism and antirealism will be properly and fruitfully developed if both parties accept the conceptual framework of minimalism. In this paper, I show that this conceptual framework commits the minimalist to the realist thesis that there are mind-independent propositions; with the consequence that minimalism is not neutral to realism and antirealism. I suggest that Wright could avert this conclusion if he rejected the customary interpretation of the Equivalence Schema according to which this Schema applies to propositions. This would however render minimalism unpalatable to philosophers who welcome the traditional reading of the Equivalence Schema and believe that propositions are bearers of truth.

Are theories ‘underdetermined by the evidence’ in any way that should worry the scientific realist? I argue that no convincing reason has been given for thinking so. A crucial distinction is drawn between data equivalence and empirical equivalence. Duhem showed that it is always possible to produce a data equivalent rival to any accepted scientific theory. But there is no reason to regard such a rival as equally well empirically supported and hence no threat to realism. Two theories are empirically equivalent if they share all consequences expressed in purely observational vocabulary. This is a much stronger requirement than has hitherto been recognised—two such ‘rival’ theories must in fact agree on many claims that are clearly theoretical in nature. Given this, it is unclear how much of an impact on realism a demonstration that there is always an empirically equivalent ‘rival’ to any accepted theory would have—even if such a demonstration could be produced. Certainly in the case of the version of realism that I defend—structural realism—such a demonstration would have precisely no impact: two empirically equivalent theories are, according to structural realism, cognitively indistinguishable.

In this paper, I explore Larry Laudan's and Jarrett Leplin's recent claim that empirically equivalent theories may be differentially confirmed. I show that their attempt to prise apart empirical equivalence and epistemic parity commits them to two principles of confirmation that Hempel demonstrated to be incompatible.

This paper criticizes the attempt to found the epistemological doctrine that all theories are evidentially underdetermined on the thesis that all theories have empirically equivalent rivals. The criticisms focus on the role of auxiliary hypotheses in prediction. It is argued, in particular, that if auxiliaries are underdetermined, then the thesis of empirical equivalence is undecidable. The inference from empirical equivalence to the underdetermination of total theories would seem to survive the criticisms, because total theories do not require auxiliaries to yield observational consequences. It is shown that, nevertheless, underdetermination cannot be established for total theories.

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.