How Do Logics Explain?

Anti-exceptionalists about logic maintain that it is continuous with the empirical sciences. Taking anti-exceptionalism for granted, we argue that traditional approaches to explanation are inadequate in the case of logic. We argue that Andrea Woody's functional analysis of explanation is a better fit with logical practice and accounts better for the explanatory role of logical theories.     

Underdetermination,realism and empirical equivalence

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.     

BOOK REVIEWS

Abstract

Theories are metaphysically equivalent just if there is no fact of the matter that could render one theory true and the other false. In this paper I argue that if we are judiciously to resolve disputes about whether theories are equivalent or not, we need to develop testable criteria that will give us epistemic access to the obtaining of the relation of metaphysical equivalence holding between those theories. I develop such ‘diagnostic’ criteria. I argue that correctly inter-translatable theories are metaphysically equivalent, and what we need are ways of determining whether a putative translation is correct or not. To that end I develop a number of tools we can employ to discern whether a translation is a correct one.     

Why We Shouldn't Swallow Worm Slices: A Case Study in Semantic Accommodation

A radical metaphysical theory typically comes packaged with a semantic theory that reconciles those radical claims with common sense. The metaphysical theory says what things exist and what their natures are, while the semantic theory specifies, in terms of these things, how we are to interpret everyday language. Thus may we “think with the learned, and speak with the vulgar.” This semantic accommodation of common sense, however, can end up undermining the very theory it is designed to protect. This paper is a case study, showing in detail how one popular version of temporal parts theory is self‐undermining. This raises the specter that the problem generalizes to other metaphysical theories. The traditional flavor of temporal parts theory, Worm Theory, claims that everyday objects are four‐dimensional space‐time worms. An alternative flavor, Slice Theory, claims that objects are not space‐time worms but are instead momentary slices of these worms. The differences, we find, are not nearly as great as advertised. In fact, the differences in the two metaphysical theories are entirely masked by compensating differences in the accompanying semantic theories. As a result, the two theories generate exactly the same truth conditions. Common sense says that I was born years ago. Slice Theory adopts a semantic theory that accommodates such claims, but in doing so, it also endorses the claim that I, like other everyday objects, persist and thus do not exist for a mere moment. That is, the metaphysical claims constitutive of Slice Theory are denied by the very semantic theory Slice Theory adopts to accommodate common sense. Slice Theory thus undermines itself.     

From Standard Scientific Realism and Structural Realism to Best Current Theory Realism

I defend a realist commitment to the truth of our most empirically successful current scientific theories—on the ground that it provides the best explanation of their success and the success of their falsified predecessors. I argue that this Best Current Theory Realism (BCTR) is superior to preservative realism (PR) and the structural realism (SR). I show that PR and SR rest on the implausible assumption that the success of outdated theories requires the realist to hold that these theories possessed truthful components. PR is undone by the fact that past theories succeeded even though their ontological claims about unobservables are false. SR backpeddles to argue that the realist is only committed to the truth about the structure of relations implied by the outdated theory, in order to explain its success. I argue that the structural component of theories is too bare-bones thin to explain the predictive/explanatory success of outdated theories. I conclude that BCTR can meet these objections to PR and SR, and also overcome the pessimistic meta-induction.     

Metaphysics as modeling: the handmaiden’s tale

Critics of contemporary metaphysics argue that it attempts to do the hard work of science from the ease of the armchair. Physics, not metaphysics, tells us about the fundamental facts of the world, and empirical psychology is best placed to reveal the content of our concepts about the world. Exploring and understanding the world through metaphysical reflection is obsolete. In this paper, I will show why this critique of metaphysics fails, arguing that metaphysical methods used to make claims about the world are similar to scientific methods used to make claims about the world, but that the subjects of metaphysics are not the subjects of science. Those who argue that metaphysics uses a problematic methodology to make claims about subjects better covered by natural science get the situation exactly the wrong way around: metaphysics has a distinctive subject matter, not a distinctive methodology. The questions metaphysicians address are different from those of scientists, but the methods employed to develop and select theories are similar. In the first section of the paper, I will describe the sort of subject matter that metaphysics tends to engage with. In the second section of the paper, I will show how metaphysical theories are classes of models and discuss the roles of experience, common sense and thought experiments in the construction and evaluation of such models. Finally, in the last section I will discuss the way these methodological points help us to understand the metaphysical project. Getting the right account of the metaphysical method allows us to better understand the relationship between science and metaphysics, to explain why doing metaphysics successfully involves having a range of different theories (instead of consensus on a single theory), to understand the role of thought experiments involving fictional worlds, and to situate metaphysical realism in a scientifically realist context.     

Frege on the generality of logical laws

Frege claims that the laws of logic are characterized by their “generality,” but it is hard to see how this could identify a special feature of those laws. I argue that we must understand this talk of generality in normative terms, but that what Frege says provides a normative demarcation of the logical laws only once we connect it with his thinking about truth and science. He means to be identifying the laws of logic as those that appear in every one of the scientific systems whose construction is the ultimate aim of science, and in which all truths have a place. Though an account of logic in terms of scientific systems might seem hopelessly antiquated, I argue that it is not: A basically Fregean account of the nature of logic still looks quite promising.     

ROCKMORE ON ANALYTIC PRAGMATISM

Abstact: This article responds critically to Tom Rockmore's essay “On Classical and Neo‐Analytic Forms of Pragmatism,” which appeared in Metaphilosophy in 2005. Rockmore charges analytic pragmatism with having a conflicted epistemology, relying on incoherent appropriations of Hegel, and maintaining an unpragmatic commitment to metaphysical realism. We rebut these charges by arguing that what Rockmore sees as conflicted in analytic pragmatist epistemology is simply fallibilism, that appropriations of Hegel needn't be as global as Rockmore claims, and that commitments to metaphysical realism need not disqualify philosophers from being pragmatists.     

The Argument from Underconsideration as Grounds for Anti‐realism: A Defence

The anti‐realist argument from underconsideration focuses on the fact that, when scientists evaluate theories, they only ever consider a subset of the theories that can account for the available data. As a result, when scientists judge one theory to be superior to competitor theories, they are not warranted in drawing the conclusion that the superior theory is likely true with respect to what it says about unobservable entities and processes. I defend the argument from underconsideration from the objections of Peter Lipton. I argue that the inconsistency that Lipton claims to find in the argument vanishes once we understand what the anti‐realist means when she claims that scientists are reliable. I also argue that collapsing the distinction between relative and absolute evaluations, as Lipton recommends, has its costs. Finally, I briefly examine Richard Boyd’s influential defence of realism.     

PRIEST AND THE BISHOP

Abstract:  According to metaphysical realism, there may be features of reality which we cannot conceive. If this thesis of cognitive closure is inconsistent, then, pace dialetheism, metaphysical realism proves incoherent. Recently, Graham Priest has revived Berkeley's idealist argument meant to show that cognitive closure is inconsistent. If cogent, this argument poses a threat to metaphysical realism. I argue that while Priest's reconstruction of Berkeley's argument may be seen to be paradoxical on one interpretation of 'conceive', that interpretation is not the intended one. On the intended interpretation, the argument fails and hence leaves metaphysical realism unassailed.     

Against Radical Quantum Ontologies

Some theories of quantum mechanical phenomena endorse wave function realism, according to which the physical space we inhabit is very different from the physical space we appear to inhabit. In this paper I explore an argument against wave function realism that appeals to a type of simplicity that, although often overlooked, plays a crucial role in scientific theory choice. The type of simplicity in question is simplicity of fit between the way a theory says the world is and the way the world appears to be. This argument can be understood as one way of spelling out the so‐called “incredulous stare objection” that is sometimes leveled against surprising metaphysical theories.     

Theism,metaphysics, and D. Z. Phillips

Section I argues that theistic religions incorporate metaphysical systems and that these systems are explanatory. Section II defends these claims against D. Z. Phillips's objections to the epistemic realism and correspondence theory of truth which they imply. I conclude by raising questions about the status of Phillips's own project.     

The logic of epistemic justification

Theories of epistemic justification are commonly assessed by exploring their predictions about particular hypothetical cases—predictions as to whether justification is present or absent in this or that case. With a few exceptions, it is much less common for theories of epistemic justification to be assessed by exploring their predictions about logical principles. The exceptions are a handful of ‘closure’ principles, which have received a lot of attention, and which certain theories of justification are well known to invalidate. But these closure principles are only a small sample of the logical principles that we might consider. In this paper, I will outline four further logical principles that plausibly hold for justification and two which plausibly do not. While my primary aim is just to put these principles forward, I will use them to evaluate some different approaches to justification and (tentatively) conclude that a ‘normic’ theory of justification best captures its logic.     

Essence and modal knowledge

During the last quarter of a century, a number of philosophers have become attracted to the idea that necessity can be analyzed in terms of a hyperintensional notion of essence. One challenge for proponents of this view is to give a plausible explanation of our modal knowledge. The goal of this paper is to develop a strategy for meeting this challenge. My approach rests on an account of modality that I developed in previous work, and which analyzes modal properties in terms of the notion of a metaphysical law (which is a generalization of the concept of an essential truth). I discuss what information about the metaphysical laws (including essential truths) is required for modal knowledge. Moreover, I describe two ways in which we might be able to acquire this information. The first way employs inference to the best explanation. The metaphysical laws, including the essential truths, play a crucial role in causal and grounding explanations and we can gain knowledge of these laws by abductive inferences from facts of which we have perceptual or a priori knowledge. The second way of gaining information about the metaphysical laws rests on knowledge that is partly constitutive of competence with the concepts that are needed to express the relevant information. Finally, I consider how knowledge of the metaphysical laws can be used to establish modal claims, paying special attention to the much-discussed connection between conceiving and possibility.

     

Why Evolution is Really Indeterministic

Leslie Graves, Barbara Horan and Alex Rosenberg (1999) have argued that the process of evolution is really deterministic, so we should be instrumentalists about our probabilistic evolutionary theory. I criticize the consistency of their view. I argue that because they are realists towards multiple theories (quantum mechanics and macrophysics) their arguments against realism for another scientific theory fail. The main point of this paper is critical, but in order to set up this criticism I explore the ramifications of realism for multiple theories. Finally, I offer a brief metaphysical justification for realism about multiple theories. This view justifies realism for evolutionary theory, which has been defended by Robert Brandon and Scott Carson (1996).     

Now is the time

The aim of this paper is to consider some logical aspects of the debate between the view that the present is the only ‘real’ time, and the view that the present is not in any way metaphysically privileged. In particular I shall set out a language of first-order predicate tense logic with a now predicate, and a first order (extensional) language with an abstraction operator, in such a way that each language can be shewn to be exactly translatable into the other. I shew that this translation is preserved at the metalinguistic level, so that equivalent truth conditions can be defined in a tensed metalanguage or an indexical metalanguage. I then make some remarks about the connection between proofs of relative consistency and metaphysical truth; and some historical remarks about Arthur Prior's use of formal logic in expressing his presentist views.     

Semantic Challenges to Scientific Realism

This paper is concerned with connections between scientific and metaphysical realism. It is not difficult to show that scientific realism, as expounded by Psillos (1999) clearly qualifies as a kind of metaphysical realism in the sense of Putnam (1980). The statement of scientific realism therefore must not only deal with underdetermination and the dynamics of scientific theories but also answer the semantic challenges to metaphysical realism. As will be argued, the common core of these challenges is the proposition that a (metaphysical) realist semantics leads to semantic agnosticism in the sense that we are unable to grasp the proper meanings and referents of our linguistic expressions. Having established this, I will focus more specifically on the question of whether scientific realism—in its state-of-the-art account—has the resources to make reference to scientific concepts intelligible such that the semantic challenges can be answered.     

Underdetermination and Meaning Indeterminacy: What is the Difference?

The first part of this paper discusses Quine’s views on underdetermination of theory by evidence, and the indeterminacy of translation, or meaning, in relation to certain physical theories. The underdetermination thesis says different theories can be supported by the same evidence, and the indeterminacy thesis says the same component of a theory that is underdetermined by evidence is also meaning indeterminate. A few examples of underdetermination and meaning indeterminacy are given in the text. In the second part of the paper, Quine’s scientific realism is discussed briefly, along with some of the difficulties encountered when considering the ‘truth’ of different empirically equivalent theories. It is concluded that the difference between underdetermination and indeterminacy, while significant, is not as great as Quine claims. It just means that after we have chosen a framework theory, from a number of empirically equivalent ones, we still have further choices along two different dimensions.     

On inconsistent entities. A reply to Colyvan

In a recent article M. Colyvan has argued that Quinean forms of scientific realism are faced with an unexpected upshot. Realism concerning a given class of entities, along with this route to realism, can be vindicated by running an indispensability argument to the effect that the entities postulated by our best scientific theories exist. Colyvan observes that among our best scientific theories some are inconsistent, and so concludes that, by resorting to the very same argument, we may incur a commitment to inconsistent entities. Colyvan’s argument could be interpreted, and in part is presented, as a reductio of Quinean scientific realism; yet, Colyvan in the end manifests some willingness to bite the bullet, and provides some reasons why we shouldn’t feel too uncomfortable with those entities. In this paper we wish to indicate a way out to the scientific realist, by arguing that no indispensability argument of the kind suggested by Colyvan is actually available. To begin with, in order to run such an indispensability argument we should be justified in believing that an inconsistent theory is true; yet, in so far as the logic we accept is a consistent one it is arguable that our epistemic predicament could not be possibly one in which we are justified in so believing. Moreover, also if our logic admitted true contradictions, as Dialetheism does, it is arguable that Colyvan’s indispensability argument could not rest on a true premise. As we will try to show, dialetheists do not admit true contradictions for cheap: they do so just as a way out of paradox, namely whenever we are second-level ignorant as to the metaphysical possibility of evidence breaking the parity among two or more inconsistent claims; Colyvan’s examples, however, are not of this nature. So, even under the generous assumption that Dialetheism is true, we will conclude that Colyvan’s argument doesn’t achieve its surprising conclusion.     

Direct perception and the predictive mind

Predictive approaches to the mind claim that perception, cognition, and action can be understood in terms of a single framework: a hierarchy of Bayesian models employing the computational strategy of predictive coding. Proponents of this view disagree, however, over the extent to which perception is direct on the predictive approach. I argue that we can resolve these disagreements by identifying three distinct notions of perceptual directness: psychological, metaphysical, and epistemological. I propose that perception is plausibly construed as psychologically indirect on the predictive approach, in the sense of being constructivist or inferential. It would be wrong to conclude from this, however, that perception is therefore indirect in a metaphysical or epistemological sense on the predictive approach. In the metaphysical case, claims about the inferential properties of constructivist perceptual mechanisms are consistent with both direct and indirect solutions to the metaphysical problem of perception (e.g. naïve realism, representationalism, sense datum theory). In the epistemological case, claims about the inferential properties of constructivist perceptual mechanisms are consistent with both direct and indirect approaches to the justification of perceptual belief. In this paper, I demonstrate how proponents of the predictive approach have conflated these distinct notions of perceptual directness and indirectness, and I propose alternative strategies for developing the philosophical consequences of the approach.