Logical abductivism is the epistemic view about logic according to which logical theories are justified by abduction (or Inference to the Best Explanation), that is on how well they explain the relevant evidence, so that the correct logical theory turns out to be the one that explains it best. Arguably, this view should be equally applied to both deductive and non-deductive logics, abduction included. But while there seems to be nothing wrong in principle in using abduction to determine the (...) correct logical theories of deduction and induction, things might be more complicated regarding logical theories of abduction. We may wonder whether allowing for an abductive justification of a theory of abduction is an epistemically legitimate move, since here circularity casts its shadow and makes the situation darker. This is the issue to which this work is devoted. I will defend that, to be effective, an abductive justification for a theory of abduction calls for a justification of abduction in advance, which we do not yet have. (shrink)

Logical abductivism features in the recent literature as a _new epistemology_ for logic, in connection with logical anti-exceptionalism. According to this account, (i) logical knowledge is obtained by the justified _choice_ of a logical theory using abduction, which (ii) _replaces_ problematic approaches in traditional logical epistemology. We argue that such claims are not properly warranted; they conflate justification and theory choice methods. Abduction requires that one starts with _justified data_, and justification, in such cases, needs to appeal to sources (...) that are not granted by abduction. In this sense, abduction cannot be all there is to the epistemology of logic. Some abductivists, we shall see, even appeal to methods of the traditional epistemology to obtain the data. Keeping justification and theory choice separated may contribute to avoid obscurities in discussion of the nature of data in logic and in understanding more clearly how to frame the anti-exceptional nature of logic. (shrink)

I argue against abductivism about logic, which is the view that rational theory choice in logic happens by abduction. Abduction cannot serve as a neutral arbiter in many foundational disputes in logic because, in order to use abduction, one must first identify the relevant data. Which data one deems relevant depends on what I call one's conception of logic. One's conception of logic is, however, not independent of one's views regarding many of the foundational disputes that one may hope (...) to solve by abduction. (shrink)

Logic, in one of the many sense of that term, is a theory about what follows from what and why. Arguably, the correct theory has to be determined by abduction. Over recent years, so called logical anti-exceptionalists have investigated this matter. Current discussions have been restricted to deductive logic. However, there are also, of course, various forms of non-deductive reasoning. Indeed, abduction itself is one of these. What is to be said about the way of choosing the best theory of (...) non-deductive inferences? It would seem clear that an anti-exceptionalist should hold that essentially the same method of choice should apply to non-deductive logic. A number of issues need to be faced in the process, not the least of which is the circularity involved in an abductive justification for a theory of abduction. This paper discusses matters. (shrink)

Logical abductivism is the method which purports to use Inference to the Best Explantion (IBE) to determine the best logical theory. The present essay argues that this is not the case, since the method fails to meet the criteria requisite for the fruitful application of IBE. This occurs due to an intrinsic difficulty in choosing the appropriate evidence and theoretical virtues which guide theory revision in logic: one’s previous conception of logic influences both these choices. Logical abductivism fails, (...) moreover, to select the best logical theory, exactly because a lack of agreement on theory and virtues for Logic. Rather than direct comparison between two options, a more suitable approach to theory revision in logic is piecemeal, because this method neither assumes nor needs a neutral ground from which to start revising theories. (shrink)

Abstract: According to Laurence BonJour, the problem of induction can be solved by recognizing the a priori necessity that inductive conclusions constitute the best explanations of inductive premises. I defend an interpretation of the key probability claims BonJour makes about inductive premises and show that they are not susceptible to many of the objections that have been lodged against them. I then argue that these purportedly necessary probability claims nevertheless remain deeply problematic and that, as a result, BonJour's proposal fails (...) to provide a satisfactory resolution of the problem of induction. (shrink)

The notion of strength has featured prominently in recent debates about abductivism in the epistemology of logic. Following Williamson and Russell, we distinguish between logical and scientific strength and discuss the limits of the characterizations they employ. We then suggest understanding logical strength in terms of interpretability strength and scientific strength as a special case of logical strength. We present applications of the resulting notions to comparisons between logics in the traditional sense and mathematical theories.

Abductivists claim that explanatory considerations (e.g., simplicity, parsimony, explanatory breadth, etc.) favor belief in the external world over skeptical hypotheses involving evil demons and brains in vats. After showing how most versions of abductivism succumb fairly easily to obvious and fatal objections, I explain how rationalist versions of abductivism can avoid these difficulties. I then discuss the most pressing challenges facing abductivist appeals to the a priori and offer suggestions on how to overcome them.

Drawing on the epistemology of logic literature on anti-exceptionalism about logic, we set out to investigate the following metaphilosophical questions empirically: Is philosophy special? Are its methods (dis)continuous with science? More specifically, we test the following metaphilosophical hypotheses empirically: philosophical deductivism, philosophical inductivism, and philosophical abductivism. Using indicator words to classify arguments by type (namely, deductive, inductive, and abductive arguments), we searched through a large corpus of philosophical texts mined from the JSTOR database (N = 435,703) to find patterns (...) of argumentation. The results of our quantitative, corpus-based study suggest that deductive arguments are significantly more common than abductive arguments and inductive arguments in philosophical texts overall, but they are gradually and steadily giving way to non-deductive (i.e. inductive and abductive) arguments in academic philosophy. (shrink)

Given the plethora of competing logical theories of validity available, it’s understandable that there has been a marked increase in interest in logical epistemology within the literature. If we are to choose between these logical theories, we require a good understanding of the suitable criteria we ought to judge according to. However, so far there’s been a lack of appreciation of how logical practice could support an epistemology of logic. This paper aims to correct that error, by arguing for a (...) practice-based approach to logical epistemology. By looking at the types of evidence logicians actually appeal to in attempting to support their theories, we can provide a more detailed and realistic picture of logical epistemology. To demonstrate the fruitfulness of a practice-based approach, we look to a particular case of logical argumentation—the dialetheist’s arguments based upon the self-referential paradoxes—and show that the evidence appealed to support a particular theory of logical epistemology, logical abductivism. (shrink)

Logical anti‐exceptionalism is the view that logic is not special, it is continuous with science. This continuity is typically understood in terms of the use of the abductive method in logical theory choice, with logical knowledge resulting from our choice of the theory best accounting for the data. In this paper, we argue for two related claims: (i) that this understanding of the continuity between logic and science faces considerable challenges; and (ii) that such challenges may be avoided by elaborating (...) the continuity of logic with science in terms of the “logic‐as‐models” approach. More specifically, we defend that logical theories should be seen in the lights of the “models‐as‐epistemic‐tools” approach, an approach to the nature of models in empirical science more closely connected with current scientific practice. The result is a version of logical anti‐exceptionalism opening new perspectives for the philosophical understanding of logic. (shrink)

According to methodological anti-exceptionalism, logic follows a scientific methodology. There has been some discussion about which methodology logic has. Authors such as Priest, Hjortland and Williamson have argued that logic can be characterized by an abductive methodology. We choose the logical theory that behaves better under a set of epistemic criteria. In this paper, I analyze some important discussions in the philosophy of logic, and I show that they presuppose different methodologies, involving different notions of evidence and different epistemic values. (...) I argue that, rather than having a specific methodology such as abductivism, logic can be characterized by methodological pluralism. This position can also be seen as the application of scientific pluralism to the realm of logic. (shrink)

We ordinarily take it as obvious that we acquire knowledge of our world on the basis of sensory perception, and that such knowledge plays a central cognitive and practical role in our lives. Upon reflection, however, it is far from obvious what perception involves and how exactly it contributes to our knowledge. Indeed, skeptical arguments have led some to question whether we have any knowledge, or even rational or justified belief, regarding the world outside our minds. -/- Investigating the nature (...) and scope of our perceptual knowledge and perceptually justified belief, A Critical Introduction to the Epistemology of Perception provides an accessible and engaging introduction to a flourishing area of philosophy. Before introducing and evaluating the main theories in the epistemology of perception, Ali Hasan sets the stage with a discussion of skepticism, realism, and idealism in early modern philosophy, theories of perceptual experience (sense-datum theory, adverbialism, intentionalism, and metaphysical disjunctivism), and central controversies in general epistemology. Hasan then surveys the main theories in the contemporary debate, including coherentism, abductivism, phenomenal conservatism or dogmatism, reliabilism, and epistemological disjunctivism, presenting the motivations and primary objections to each. Hasan also shows how to avoid confusing metaphysical issues with epistemological ones, and identifies interesting connections between the epistemology and metaphysics of perception. -/- For students in epistemology or the philosophy of perception looking to better understand the central questions, concepts, and debates shaping contemporary epistemology, A Critical Introduction to the Epistemology of Perception is essential reading. (shrink)

Below are reflections on Peirce’s conception of abductive methods and Russell’s conception of regressive methods. Along the way, it will be necessary to examine the marked differences between Russell and Frege on the ins and outs of logicism, from which latter the regressivist ideas first emerged. Russell was aware of Peirce’s contributions to the algebraization of logic and Peirce was aware of Russell’s writings on logicism. However, in framing his thoughts about regressive methods, Russell showed no familiarity with Peirce’s treatment (...) of abductive methods. In 1907, Russell read to the Cambridge Mathematics Club an essay entitled “The regressive method of discovering the premises of mathematics.” Since that paper didn’t see the published light of day until three years after Russell’s death in 1970, Peirce couldn’t have taken notice of it in developing his ideas about abduction. Even so, it has been suggested that there exists a noteworthy similarity between Russell’s regressivism and Peirce’s abductivism. The principal purpose of this essay is to show the resemblance to have been misjudged, in which case, my title would have to be corrected. (shrink)

Anti-exceptionalists about logic claim that logical methodology is not different from scientific methodology when it comes to theory choice. Two anti-exceptionalist accounts of theory choice in logic are abductivism and predictivism. These accounts have in common reliance on pre-theoretical logical intuitions for the assessment of candidate logical theories. In this paper, I investigate whether intuitions can provide what abductivism and predictivism want from them and conclude that they do not. As an alternative to these approaches, I propose a (...) Carnapian view on logical theorizing according to which logical theories do not simply account for pre-theoretical intuitions, but rather improve on them. In this account, logical theories are ameliorative, rather than representational. (shrink)

The abductivist reply to skepticism is the view that commonsense explanations of the patterns and regularities that appear in our sensory experiences should be rationally preferred to skeptical explanations of those same patterns and regularities on the basis of explanatory considerations. In this article I critically examine Laurence BonJour’s rationalist version of the abductivist position. After explaining why BonJour’s account is more defensible than other versions of the view, I argue that the notion of probability he relies upon is deeply (...) problematic, that he incorporates an implausible double-standard concerning a priori and a posteriori justification, and that his view is vulnerable to skepticism about the a priori. I suggest that some of these problems are due to idiosyncratic commitments BonJour makes and that abductivists would be better off without them. I conclude with some suggestions about how to improve BonJour’s abductivist response to skepticism. (shrink)

This paper is about the pragmatic inferences in play as conversational implicatures (Grice, P. 1989. Studies in the way of words. Cambridge, MA: Harvard University Press) occur. First, it constructs the deductivism versus abductivism debate that transpires from the extant literature but is rarely elaborated. Against deductivism, the paper argues that implicating inferences in conversational implicatures can instantiate an abductive logical form, as abductivism suggests. Against abductivism, however, it grants to deductivism that implicating inferences can have a (...) deductive form provided the latter is of a defeasible type. In sum, it thus argues for pluralist defeasibilism. Second, it turns to the issue of the ontological nature of implicating inferences and advocates normative inferentialism, on which these inferences are not primarily real psychological processes but rules of the practice of implicating. While this allows for the possibility of their psychological instantiation, to be sure, the paper also insists that psychological inferring processes in implicatures are neither necessarily isomorphic to the aforementioned rules nor even necessarily occur as an implicature occurs. (shrink)

We face reality presented with the data of conscious experience and nothing else. The project of early modern philosophy was to build a complete theory of the world from this starting point, with no cheating. Crucial to this starting point is the data of conscious sensory experience – sense data. Attempts to avoid this project often argue that the very idea of sense data is confused. But the sense-data way of talking, the sense-data language, can be freed from every blemish (...) using ideas from contemporary metaontology. We can adopt a sense-data framework that vindicates the traditional claims of sense-data theories and leads to plausible theories of perception and color. We can, we should, and in a sense, we must. Yet when we do, we face the traditional problem of external world skepticism, head-on. The real challenge of skepticism is forced upon us; it cannot honestly be avoided using externalist tricks, burden of proof shifting, or other razzle dazzle. But the challenge can be met: we are rational to posit the external world as the best explanation of the many synchronic and diachronic patterns over our sense-data. This paper argues for all of these points and ends with a plea for analytic empiricism – a traditional sense-data version of empiricism that uses all of the tools of analytic philosophy while avoiding the more questionable doctrines of the Vienna Circle (phenomenalism, verificationism). Analytic empiricism is our last best hope for completing the great philosophical project of early modern philosophy. (shrink)

Anti-exceptionalism about logic is the thesis that logic is not special. In this paper, I consider, and reject, a challenge to this thesis. According to this challenge, there are basic logical principles, and part of what makes such principles basic is that they are epistemically exceptional. Thus, according to this challenge, the existence of basic logical principles provides reason to reject anti-exceptionalism about logic. I argue that this challenge fails, and that the exceptionalist positions motivated by it are thus unfounded. (...) I make this case by disambiguating two senses of ‘basic’ and showing that, once this disambiguation is taken into account, the best reason we have for thinking that there are basic principles actually implies that those principles do not require a special epistemology. Consequently, the existence of basic logical principles provides reason to accept, rather than reject, anti-exceptionalism concerning the epistemology of logic. I conclude by explaining how an abductivist, anti-exceptionalist approach to the epistemology of logic can accommodate the notion of basic logical principles. (shrink)

Some philosophers argue that we are justified in rejecting skepticism because it is explanatorily inferior to more commonsense hypotheses about the world. Focusing on the work of Jonathan Vogel, I show that this “abductivist” or “inference to the best explanation” response rests on an impoverished explanatory framework which ignores the explanatory gap between an object's having certain properties and its appearing to have those properties. Once this gap is appreciated, I argue, the abductivist strategy is defeated.

An important line of response to scepticism appeals to the best explanation. But anti-sceptics have not engaged much with work on explanation in the philosophy of science. I plan to investigate whether plausible assumptions about best explanations really do favour anti-scepticism. I will argue that there are ways of constructing sceptical hypotheses in which the assumptions do favour anti-scepticism, but the size of the support for anti-scepticism is small.

A key question in the philosophy of logic is how we have epistemic justification for claims about logical entailment (assuming we have such justification at all). Justification holism asserts that claims of logical entailment can only be justified in the context of an entire logical theory, e.g., classical, intuitionistic, paraconsistent, paracomplete etc. According to holism, claims of logical entailment cannot be atomistically justified as isolated statements, independently of theory choice. At present there is a developing interest in—and endorsement of—justification holism (...) due to the revival of an abductivist approach to the epistemology of logic. This paper presents an argument against holism by establishing a foundational entailment-sentence of deduction which is justified independently of theory choice and outside the context of a whole logical theory. (shrink)

K. R. Popper distinguished between two main uses of logic, the demonstrational one, in mathematical proofs, and the derivational one, in the empirical sciences. These two uses are governed by the following methodological constraints: in mathematical proofs one ought to use minimal logical means (logical minimalism), while in the empirical sciences one ought to use the strongest available logic (logical maximalism). In this paper I discuss whether Popper’s critical rationalism is compatible with a revision of logic in the empirical sciences, (...) given the condition of logical maximalism. Apparently, if one ought to use the strongest logic in the empirical sciences, logic would remain immune to criticism and, thus, non-revisable. I will show that critical rationalism is theoretically compatible with a revision of logic in the empirical sciences. However, a question that remains to be clarified by the critical rationalists is what kind of evidence would lead them to revise the system of logic that underlies a physical theory, such as quantum mechanics? Popper’s falsificationist methodology will be compared with the recently advocated extension of the abductive methodology from the empirical sciences to logic by T. Williamson, since both of them arrive at the same conclusion concerning the status of classical logic. (shrink)

The distinguished theologian, David Ray Griffin, has advanced a set of thirteen theses intended to characterize (what he calls) "Neo-Darwinism" and which he contrasts with "Intelligent Design". Griffin maintains that Neo-Darwinism is "atheistic" in forgoing a creator but suggests that, by adopting a more modest scientific naturalism and embracing a more naturalistic theology, it is possible to find "a third way" that reconciles religion and science. The considerations adduced here suggest that Griffin has promised more than he can deliver. On (...) his account, God is in laws of nature; therefore, any influence He exerts is natural rather than supernatural. But if the differences God makes are not empirically detectable, then Griffin's account is just as objectionable as a theory of supernatural intervention. And Griffin has not shown that evolution as distinct from his idiosyncratic sense of Neo-Darwinism is incompatible with theism. (shrink)

A common response to radical skeptical challenges to our knowledge of the external world has been that there are explanatory reasons (e.g., simplicity, coherence, explanatory power, conservatism) for favoring commonsense explanations of our sensory experiences over skeptical explanations. Despite the degree of visibility this class of response has enjoyed, it has often been viewed with skepticism [sic] by the epistemological community because of concerns about the epistemic merits of explanatory reasoning. I argue that skeptical challenges that employ skeptical hypotheses presuppose (...) central explanationist tenets and that this fact should raise one’s estimation of the strength of explanationist responses to skepticism. (shrink)

This paper develops an account of disagreement and agreement in logic in terms of rules of acceptance, rejection, and suspension of judgement. Acceptance, rejection, and suspension in logic are thereby taken to be doxastic attitudes resulting from, respectively, assenting, dissenting, or refraining from assenting and dissenting to arguments or propositions in light of their logical validity/invalidity. Disagreement between advocates of different logics is characterized as a form of doxastic noncotenability. A full account of agreement in logic does not only require (...) doxastic cotenability between two logicians. It is also necessary that they share the reasons that ground their respective doxastic attitudes. These notions of disagreement and agreement will be applied to disagreements/agreements between advocates of three different logical systems: classical logic, the paracomplete logic K3 , and the paraconsistent logic LP. In particular, it will be discussed which doxastic attitudes those logicians ought to have with regard to a proposition expressed by the Liar sentence. In the last part of the paper, it will be examined in what sense a disagreement in logic can be understood as a genuine disagreement, even if no single neutral intertheoretic concept of validity is available that is shared by all logicians. (shrink)