I objected that the defeasibility theory of knowledge prohibits you from knowing that you know that p if your knowledge that p is a posteriori. Rodrigo Borges claims that Peter Klein has already satisfactorily answered a version of my objection. He attempts to defend Klein’s reply and argues that my objection fails because a principle on which it is based is false.I will show that my objection is not a version of the old one that Klein attempts (unsuccessfully) (...) to address, that Borges’ defence of Klein’s reply fails and that his argument against my new objection leaves it untouched. (shrink)

According to the Reasoning View about normative reasons, facts about normative reasons for action can be understood in terms of facts about the norms of practical reasoning. I argue that this view is subject to an overlooked class of counterexamples, familiar from debates about Subjectivist theories of normative reasons. Strikingly, the standard strategy Subjectivists have used to respond to this problem cannot be adapted to the Reasoning View. I think there is a solution to this problem, however. I argue that (...) the norms of practical reasoning, like the norms of theoretical reasoning, are characteristically defeasible, in a sense I make precise. Recognizing this property of those norms makes space for a solution to the problem. The resulting view is in a way analogous to the familiar defeasibility theory of knowledge, but it avoids a standard objection to that theory. (shrink)

According to the so-called ‘Taking Condition’ (a label due to Boghossian 2014) on inference, for a response R in circumstances C to count as an instance of reasoning or inferring, it must be the case that the agent’s taking it that R is warranted or justified in C plays (the right sort of) explanatory role in her R-ing. The Taking Condition has come under much criticism in the theory of reasoning. While I believe that these criticisms can be answered, (...) my aim in this paper is to build a positive case for the Taking Condition. More specifically, I argue that views based on the Taking Condition do a much better job accounting for crucial features of reasoning—especially once we recognize the pervasiveness and significance of defeasibility in our reasoning. (shrink)

In recent years, the e ffort to formalize erotetic inferences (i.e., inferences to and from questions) has become a central concern for those working in erotetic logic. However, few have sought to formulate a proof theory for these inferences. To fill this lacuna, we construct a calculus for (classes of) sequents that are sound and complete for two species of erotetic inferences studied by Inferential Erotetic Logic (IEL): erotetic evocation and regular erotetic implication. While an attempt has been made (...) to axiomatize the former in a sequent system, there is currently no proof theory for the latter. Moreover, the extant axiomatization of erotetic evocation fails to capture its defeasible character and provides no rules for introducing or eliminating question-forming operators. In contrast, our calculus encodes defeasibility conditions on sequents and provides rules governing the introduction and elimination of erotetic formulas. We demonstrate that an elimination theorem holds for a version of the cut rule that applies to both declarative and erotetic formulas and that the rules for the axiomatic account of question evocation in IEL are admissible in our system. (shrink)

Two truisms about empirical justification are that experience plays a crucial role in it and that it is defeasible. There are, of course, different ways of developing these truisms into philosophical theories. I favor one particular view about the role of experience in empirical justification which may be thought to lead to problems in accommodating its defeasibility. My aim in this paper is to argue that the problems are illusory, based on an entrenched misconception how defeaters work.

Ranking theory is one of the salient formal representations of doxastic states. It differs from others in being able to represent belief in a proposition (= taking it to be true), to also represent degrees of belief (i.e. beliefs as more or less firm), and thus to generally account for the dynamics of these beliefs. It does so on the basis of fundamental and compelling rationality postulates and is hence one way of explicating the rational structure of doxastic states. (...) Thereby it provides foundations for accounts of defeasible or nonmonotonic reasoning. It has widespread applications in philosophy, it proves to be most useful in Artificial Intelligence, and it has started to find applications as a model of reasoning in psychology. (shrink)

In some recent work, John N.Williams defends a new objection to the defeasibility theory of knowledge. But the objection is of wider interest, since Williams also suggests that this style of objection may undermine other theories of knowledge. I distinguish two versions of Williams’ objection. I then show that the first version relies on false conceptual principles, and the second relies on a specific and dubious conception of the goal of the analysis of knowledge.

The paper considers contemporary models of presumption in terms of their ability to contribute to a working theory of presumption for argumentation. Beginning with the Whatelian model, we consider its contemporary developments and alternatives, as proposed by Sidgwick, Kauffeld, Cronkhite, Rescher, Walton, Freeman, Ullmann-Margalit, and Hansen. Based on these accounts, we present a picture of presumptions characterized by their nature, function, foundation and force. On our account, presumption is a modal status that is attached to a claim and has (...) the effect of shifting, in a dialogue, a burden of proof set at a local level. Presumptions can be analysed and evaluated inferentially as components of rule-based structures. Presumptions are defeasible, and the force of a presumption is a function of its normative foundation. This picture seeks to provide a framework to guide the development of specific theories of presumption. (shrink)

Despite its central role in our cognitive lives, rational belief revision has received relatively little attention from epistemologists. This dissertation begins to fill that absence. In particular, we explore the phenomenon of defeasible epistemic justification, i.e., justification that can be lost as well as gained by epistemic agents. We begin by considering extant theories of defeat, according to which defeaters are whatever cause a loss of justification or things that somehow neutralize one's reasons for belief. Both of these theories are (...) both extensionally and explanatorily inadequate and, so, are rejected. We proceed to develop a novel theory of defeat according to which defeaters are reasons against belief. According to this theory, the dynamics of justification are explained by the competition between reasons for and reasons against belief. We find that this theory not only handles the counter-examples that felled the previous theories but also does a fair job in explaining the various aspects of the phenomenon of defeat. Furthermore, this theory accomplishes this without positing any novel entities or mechanisms; according to this theory, defeaters are epistemic reasons against belief, the mirror image of our epistemic reasons for belief, rather than sui generis entities. (shrink)

Given that conspiracies exist, can we be justified in dismissing conspiracy theories without concerning ourselves with specific details? I answer this question by focusing on contrarian conspiracy theories, theories about conspiracies that conflict with testimony from reliable sources of information. For example, theories that say the CIA masterminded the assassination of John F. Kennedy, 9/11 was an inside job, or the Freemasons are secretly running the world are contrarian conspiracy theories. When someone argues for a contrarian conspiracy theory, their (...) options are to appeal to eyewitness testimony, incriminating documents, photographs, audio recordings, video recordings, allegedly scientific evidence, anomalies, or considerations of cui bono (who benefits). Most laypeople don’t know how to adequately respond to arguments for contrarian conspiracy theories, but this doesn’t mean that it’s dogmatic to reject them. I argue that many laypeople are defeasibly justified in rejecting a variety of contrarian conspiracy theories based on testimony and this justification is rarely defeated by arguments for contrarian conspiracy theories even if we don’t know how to respond to these arguments. (shrink)

In his article “Why Philosophical Theories of Evidence Are (and Ought to Be) Ignored by Scientists,” Peter Achinstein argues that philosophical theories of evidence are ignored by scientists because they rest on assumptions which make their concepts of evidence too weak for scientists to work with, or which entail that the truth or falsity of evidential statements can be determined a priori. Given that, as Achinstein argues, the truth of many evidential statements can only be determined empirically, this “a priorist” (...) assumption makes scientists consider philosophical accounts of evidence irrelevant to their work. -/- In this article I examine the value of evidence, its nature, and its relation to science. I try to show that, while Achinstein’s conclusions are mostly right, the arguments and examples he gives to support them are flawed in some of their details. Specifically, I propose an account of evidence according to which, though evidential claims are objective to a large extent, something counts as evidence only if, ultimately, it has a relation to beings for whom it counts as evidence. On this view something’s status as evidence does not derive merely from people’s beliefs, but from shared practices that are embodied in what I call contexts of inquiry. I also propose that this concept of evidence is one according to which evidential claims, though defeasible, are in one respect a priori. I argue that this account of evidence is one that should be of interest to scientists. (shrink)

This paper investigates the logic of reasons. Its aim is to provide an analysis of the sentences of the form ‘p is a reason for q’ that yields a coherent account of their logical properties. The idea that we will develop is that ‘p is a reason for q’ is acceptable just in case a suitably defined relation of incompatibility obtains between p and ¬q. As we will suggest, a theory of reasons based on this idea can solve three (...) challenging puzzles that concern, respectively, contraposing reasons, conflicting reasons, and supererogatory reasons, and opens a new perspective on some classical issues concerning non-deductive inferences. (shrink)

This dissertation defends a “non-ideal theory” of justice: a systematic theory of how to respond justly to injustice. Chapter 1 argues that contemporary political philosophy lacks a non-ideal theory of justice, and defends a variation of John Rawls’ famous original position – a Non-Ideal Original Position – as a method with which to construct such a theory. Chapter 1 then uses the Non-Ideal Original Position to argue for a Fundamental Principle of Non-Ideal Theory: a principle (...) that requires injustices to be dealt with in whichever way will best satisfy the preferences of all relevant individuals, provided those individuals are all rational, adequately informed, broadly moral, and accept the correct “ideal theory” of fully just conditions. Chapter 2 then argues for the Principle of Application – an epistemic principle that represents the Fundamental Principle’s satisfaction conditions in terms of the aims of actual or hypothetical reformist groups. Chapters 3-5 then use these two principles to argue for substantive views regarding global/international justice. Chapter 3 argues that the two principles establish a higher-order human right for all other human rights to promoted and protected in accordance with the two principles of non-ideal theory. Chapter 4 argues that the two principles defeasibly require the international community to tolerate unjust societies, provided those societies respect the most basic rights of individuals. Finally, Chapter 5 argues that the two principles imply a duty of the international community to ameliorate the most severe forms of global poverty, as well as a duty to pursue “fair trade” in international economics. (shrink)

I argue that recent rationalists' accounts of a priori knowledge suffer from two substantial weaknesses: an inadequate phenomenology of a priori insight , and the error of psychologism. I show that Husserl's theory of a priori knowledge presents a defensible and viable alternative for the contemporary rationalist, an alternative that addresses both the ontology and phenomenology of rational intuition, as well as such contemporary concerns as the possibility and character of a priori error, the empirical defeasibility of a (...) priori claims, the relation of mind to necessity, and the role of conception and imagination in a priori knowledge. Consequently, I conclude that Husserl's theory provides the needed response to the 20 th century critique of rationalism, and its attendant a priorism, as mysterious and obscure. (shrink)

This is a very selective survey of developments in epistemology, concentrating on work from the past twenty years that is of interest to philosophers of science. The selection is organized around interesting connections between distinct themes. I first connect issues about skepticism to issues about the reliability of belief-acquiring processes. Next I connect discussions of the defeasibility of reasons for belief to accounts of the theory-independence of evidence. Then I connect doubts about Bayesian epistemology to issues about the (...) content of perception. The last detailed connection is between considerations of the finiteness of cognition and epistemic virtues. To connect the connections I end by briefly discussing the pressure that consideration of social roles in the transmission of belief puts on the purposes of epistemology. (shrink)

A growing number of authors defend putative examples of knowledge from falsehood (KFF), inferential knowledge based in a critical or essential way on false premises, and they argue that KFF has important implications for many areas of epistemology (whether evidence can be false, the Gettier debate, defeasibility theories of knowledge, etc.). I argue, however, that there is no KFF, because in any supposed example either the falsehood does not contribute to the knowledge or the subject lacks knowledge. In particular, (...) I show that if the subject actually has knowledge in putative KFF cases, then there is always a veridical evidential path meeting the basing conditions that accounts for her knowledge; if there is no such path, then the subject is in a type of Gettier case. All the recent arguments that rely on KFF are therefore based on a mistake. (shrink)

In this article, we redefine classical notions of theory reduction in such a way that model-theoretic preferential semantics becomes part of a realist depiction of this aspect of science. We offer a model-theoretic reconstruction of science in which theory succession or reduction is often better - or at a finer level of analysis - interpreted as the result of model succession or reduction. This analysis leads to 'defeasible reduction', defined as follows: The conjunction of the assumptions of a (...) reducing theory T with the definitions translating the vocabulary of a reduced theory T' to the vocabulary of T, defeasibly entails the assumptions of reduced T'. This relation of defeasible reduction offers, in the context of additional knowledge becoming available, articulation of a more flexible kind of reduction in theory development than in the classical case. Also, defeasible reduction is shown to solve the problems of entailment that classical homogeneous reduction encounters. Reduction in the defeasible sense is a practical device for studying the processes of science, since it is about highlighting different aspects of the same theory at different times of application, rather than about naive dreams concerning a metaphysical unity of science. (shrink)

You reach for the bowl with ‘sugar’ written on it only to discover, from the bad taste of your coffee, that it contained salt. Mundane experiences like these show that epistemic justification does not necessarily hold stable across possible changes of information. One can be justified in believing a proposition at a certain time (that the bowl contains sugar) and cease to be justified at a later time, as one enlarges one’s epistemic perspective (as one drinks a salty coffee). When (...) this happens, one’s justification has been defeated. An epistemic defeater, broadly speaking, is that in terms of which the defeat of justification proceeds. The notion of an epistemic defeater is mostly associated with J. Pollock’s work on reasoning and inference. Pollock has provided the canonical definition of an epistemic defeater and proposed an influential taxonomy in terms of the way different types of defeaters induce their characteristic effects. The notion of an epistemic defeater has acquired a broader meaning in current epistemology, and several distinctions have been introduced that have contributed to a more nuanced understanding of the phenomenon of defeat as well as to complement Pollock’s original taxonomy. The correlated notion of a propositional defeater, defined in terms of would-be defeat of justification, is appealed to by the proponents of the defeasibility theory in the parallel debate about knowledge to explain what prevents a justified true belief from constituting knowledge in Gettier cases. (shrink)

Drawing on the puzzling behavior of ordinary knowledge ascriptions that embed an epistemic (im)possibility claim, we tentatively conclude that it is untenable to jointly endorse (i) an unfettered classical logic for epistemic language, (ii) the general veridicality of knowledge ascription, and (iii) an intuitive ‘negative transparency’ thesis that reduces knowledge of a simple negated ‘might’ claim to an epistemic claim without modal content. We motivate a strategic trade-off: preserve veridicality and (generalized) negative transparency, while abandoning the general validity of contraposition. (...) We criticize various approaches to incorporating veridicality into domain semantics, a paradigmatic ‘information-sensitive’ framework for capturing negative transparency and, more generally, the non-classical behavior of sentences with epistemic modals. We then present a novel information-sensitive semantics that successfully executes our favored strategy: stable acceptance semantics, extending a vanilla bilateral state-based semantics for epistemic modals with a knowledge operator loosely inspired by the defeasibility theory of knowledge. (shrink)

Virtue reliabilism provides an account of epistemic integration that explains how a reliable-belief forming process can become a knowledge-conducive ability of one’s cognitive character. The univocal view suggests that this epistemic integration can also explain how an external process can extend one’s cognition into the environment. Andy Clark finds a problem with the univocal view. He claims that cognitive extension is a wholly subpersonal affair, whereas the epistemic integration that virtue reliabilism puts forward requires personal-level agential involvement. To adjust the (...) univocal view, Clark recommends a subpersonal epistemic integration account that also paves way for a wholly subpersonal epistemology. Accordingly, an epistemic agent can take responsibility for her reliable belief-forming process by way of entirely subpersonal mechanisms. The aim of this thesis is to argue against a subpersonal epistemology and the need for it. First, I bring into question the conditions that motivate extended cognition: the so-called ‘glue and trust’ requirements and the functional parity principle. Neither of these conditions demands that extension should be understood in entirely subpersonal terms. On the contrary, the glue and trust conditions suggest that agents should personally and actively engage with their external vehicles to extend cognition. Further, I consider an important disparity between the two kinds of integration. Integration that prompts extension can happen immediately, but the integration that makes a reliable belief-forming process knowledge-conducive is almost always a slow process. In light of this and other similar inconsistencies between the two integration accounts, I conclude that a type of univocal view is difficult to defend. And, since that type of univocal view is the main reason for a subpersonal epistemology, the need for it does not arise. Next, I locate Clark’s main motivation for his subpersonal epistemology in his account of the predictive brain. While the predictive brain provides useful insight into how an external process might extend one’s cognition, I show it runs into problems when it tries to account for epistemic integration. Then, I explore how the concept of epistemic defeaters informs epistemic integration. Agents have to meet a specific no-defeater condition to be sensitive to the reliability of their belief-forming processes and to employ them responsibly. In an entirely subpersonal epistemology, defeasibility theory has no means to explain how an agent is rendered sensitive to the reliability of her process. Subpersonal mechanisms can become sensitive to the new process, but that does not allow the agent to employ said process responsibly. Finally, I use an AI case, based on Amazon Alexa, to argue that all accounts of epistemic integration ought to explicitly describe how one’s subpersonal mechanisms link to one’s whole person, even if the link is weak and indirect. Without this connection between one’s subpersonal mechanisms and one’s person, it can become difficult to ascribe beliefs to the agent. This becomes apparent when Alexa leads to ever-increasing layers of cognitive, mental, and agential extension. (shrink)

John N. Williams argued that Peter Klein's defeasibility theory of knowledge excludes the possibility of one knowing that one has (first-order) a posteriori knowledge. He does that by way of adding a new twist to an objection Klein himself answered more than forty years ago. In this paper I argue that Williams' objection misses its target because of this new twist.

I will discuss a variety of cases such that the subject's believing truly is somewhat of an accident, but less so than in a Gettier case. In each case, this is because her reasons are not ultimately undefeated full stop, but they are ultimately undefeated with certain qualifications. For example, the subject's reasons might be ultimately defeated considered in themselves but ultimately undefeated considered as a proper part of an inference to the best explanation that is undefeated without qualification. In (...) each section of the paper, I consider different qualifications and show how in each case we get an epistemic standing I call “coach-class knowledge”. First-class knowledge requires justifying reasons that are undefeated without qualification. Coach-class knowledge only requires qualified lack of defeat. I will use this distinction to bring debates over knowledge from falsehood and fake barns to an ecumenical resolution. In both cases, the subject enjoys coach-class rather than first-class knowledge. I will also show that the defeasible reasoning tradition can better account for graded accidental truth than safety theories. (shrink)

According to conciliatory views on the significance of disagreement, it’s rational for you to become less confident in your take on an issue in case your epistemic peer’s take on it is different. These views are intuitively appealing, but they also face a powerful objection: in scenarios that involve disagreements over their own correctness, conciliatory views appear to self-defeat and, thereby, issue inconsistent recommendations. This paper provides a response to this objection. Drawing on the work from defeasible logics paradigm and (...) abstract argumentation, it develops a formal model of conciliatory reasoning and explores its behavior in the troubling scenarios. The model suggests that the recommendations that conciliatory views issue in such scenarios are perfectly reasonable—even if outwardly they may look odd. (shrink)

The article examines the issue of a necessary connection between the phenomena of law and morality. According to legal positiv- ism, morality is not a criterion of the legitimacy for legal norms. The law can have any content including absolutely immoral (the so-called “separability thesis”). Law issues are not connected with discussing the moral merits of a possible judicial decision. They are only closely related to studying various purely legal phenomena like precedents, judicial discretion, legislatures, etc. The ascriptive legal statements (...) theory proposed by the Oxford School of Law (Herbert Hart, Joseph Raz, and others) serves as the core of contemporary legal positivism. This theory is based on the notion of defeasibility for legal responsibility without any moral reasoning. There, phenomena of law are interpreted as purely linguistic, not social constructions. Analysis of pure law language should provide all the needful tools to extract hidden meaning from any legal norm. This analysis does not require going beyond the legal language since it does not describe any real situations in the world, but merely expresses legal requirements, allowing to legally qualify some observed events. It completely eliminates any references to moral principles from the analysis of legal language. However the critical reconstruction theory of ascriptive legal statements shows limitations of the legal positivism’s analytical approach to the phenomena of law. The example of a fictitious legal collision offered demonstrates limitations of the legal positivism approach to the understand- ing of law phenomena. This collision is a complex conceptual mix of Frankfurt-style examples and imaginary situations in the Trolley Problem widely known in analytical ethics. It clearly demonstrates the possible paradox of a law judgment in situations where conditions for the recognition and cancellation of legal liability are the property of two different (not necessarily openly contradictory) legal norms. It can serve as a strong argument in favor of contemporary theories of natural law (Lon Fuller, John Finnis, Ronald Dworkin, and others), which questioned the possibility of creating a theory of pure law. They considered it senseless and impossible to draw any strict border between moral and legal norms. Immoral law cannot have the particular property of creating a moral obliga- tion to follow such like a law. Law cannot be built on legality only, and the answers to all significant legal questions should be found in moral theories. (shrink)

In a 2002 article Stewart Cohen advances the “bootstrapping problem” for what he calls “basic justification theories,” and in a 2010 followup he offers a solution to the problem, exploiting the idea that suppositional reasoning may be used with defeasible as well as with deductive inference rules. To curtail the form of bootstrapping permitted by basic justification theories, Cohen insists that subjects must know their perceptual faculties are reliable before perception can give them knowledge. But how is such knowledge of (...) reliability to be acquired if not through perception itself? Cohen proposes that such knowledge may be acquired a priori through suppositional reasoning. I argue that his strategy runs afoul of a plausible view about how epistemic principles function; in brief, I argue that one must actually satisfy the antecedent of an epistemic principle, not merely suppose that one does, to acquire any justification by its means – even justification for a merely conditional proposition. (shrink)

This dissertation is about the relationship between Epistemology and other domains. In it I want to show that in an important sense, Epistemology is an autonomous domain. That is, epistemic vocabulary (e.g., “knowledge”, “justification”, “rationality”, “epistemic reason”, etc.) cannot be analyzed without remainder into non-epistemic vocabulary. Epistemic phenomena must be explained in terms of epistemic reasons and the form of assessment proprietary to them. Although epistemic vocabulary cannot be reduced to the vocabulary of other domains, Epistemology is nonetheless connected with (...) other domains in an important way. In this dissertation I focus on the connection between Epistemology and the Philosophy of Mind. I distinguish different forms cognitive self-monitoring can take and corresponding forms of cognitive autonomy. The kind of self-monitoring that receives the most attention involves simulating interpersonal argumentation. I argue that the capacity to self-monitor in this way grounds familiar epistemic standards (e.g., knowledge and justification) and explains how reasons get their grip on us. On the picture that emerges, Epistemology and Philosophy of Mind need to be done in tandem. Epistemology gives us the normative framework that is modeled by the self-monitoring system. The self-monitoring system, conversely, explains the kind of activity we engage in that makes that normative framework applicable to us. Epistemic reasons themselves are just episodes of this kind of activity. In Chapter 1 I argue that epistemic luck cannot be analyzed in non-epistemic terms. Here I generalize Jennifer Lackey’s criticism of Duncan Pritchard’s safety-based account of epistemic luck to all reductive theories. I argue that they will either be extensionally inadequate, or they will illicitly presuppose the vocabulary they are trying to reduce. The upshot is that epistemic luck can only be understood in terms of the epistemic assessment of reasons. By extension, we can’t give a reductive analysis of knowledge. This is not to say we cannot analyze knowledge, just that we can’t analyze away the epistemic vocabulary without remainder. In chapter 2 I explain the relation between epistemic luck, epistemic justification, and knowledge. I argue that previous work in the defeasible reasoning tradition, despite being on the right track, fell short of realizing its full potential. This is because the account of how these three things relate given by its proponents was insufficiently unified, which encouraged many epistemologists to abandon the defeasible reasoning tradition entirely. I argue that a unified and principled account of their relation is possible, and it allows for an elegant analysis of knowledge. In slogan form: good reasons are apparent to the knowing subject. In chapter 3 I extend the defeasible reasoning tradition to explain how knowledge is gradable. I show that this enables us to bring the debates about fake barns and knowledge from falsehoods to ecumenical resolutions, while also shedding light on a new kind of case. Furthermore, I explain how background assumptions are themselves defeasible and some of the epistemic significance of this fact. In chapter 4 I make the connection between Epistemology and Philosophy of Mind. I argue that the self-monitoring system of cognitively mature humans uses a model of the normative framework described in the previous chapters to regulate its own cognition. Here I build on that claim to develop an account of the role played by knowledge and justification in doxastic social coordination. I build on the claim that background assumptions are themselves defeasible to develop an account of the foundations of knowledge according to which they are social but not brutely sociological. In chapter 5 I discuss the relation between the epistemic states of cognitively mature humans, children, and non-human animals. I do this in a way meant to integrate an insight from virtue epistemology into the reasons-first picture developed here: positive epistemic standing is a state attributable to the subject. In chapter 6 I discuss the metaphysics of epistemic reasons. I claim that they are episodes of the activity of reasoning. In the preceding chapters, we get a sense of what that activity involves. Here I argue that the materials developed there put us in a position to understand what epistemic reasons are. This account incorporates the insights of rival positions while sidestepping familiar objections to them. The resulting picture is in line with the non-reductive approach to the epistemic developed so far. In fact, it goes further than other “reasons-first” approaches to Epistemology by claiming that reasons are not only basic within Epistemology, but they are also basic full-stop. One key consideration for my argument here is that reasons are, by their very nature, competitors. Although this point is generally acknowledged in the literature on reasons, its consequences for the metaphysics of reasons hasn’t been. Participants in the debate about the metaphysics of reasons typically try to identify reasons with something (e.g., facts or mental states) that are either not competitors, or only competitors insofar as they constitute, or bear on the epistemic assessment of, episodes of reasoning. (shrink)

This article offers a simple technical resolution to the problem of induction, which is to say that general facts are not always inferred from observations of particular facts, but are themselves sometimes defeasibly observed. The article suggests a holistic account of observation that allows for general statements in empirical theories to be interpreted as observation reports, in place of the common but arguably obsolete idea that observations are exclusively particular. Predictions and other particular statements about unobservable facts can then appear (...) as deductive consequences of such general observation statements, rather than inductive consequences of other particular statements. This semantic shift resolves the problem by eliminating induction as a basic form of inference, and folding the justification of general beliefs into the more basic problem of perception. (shrink)

We look into the ontology of quantum theory as distinct from that of the classical theory in the sciences. Theories carry with them their own ontology while the metaphysics may remain the same in the background. We follow a broadly Kantian tradition, distinguishing between the noumenal and phenomenal realities where the former is independent of our perception while the latter is assembled from the former by means of fragmentary bits of interpretation. Theories do not tell us how the (...) noumenal world is constituted but are conceptual constructs applying to models generated in the phenomenal world within limited contexts. -/- The ontology of quantum theory principally rests on the view that entities in the world are pervasively correlated with one another not by means of probabilities as in the case of the classical theory, but by means of probability amplitudes involving finely tuned phases characterising the oscillatory behaviour of quantum mechanical states. -/- The amplitude-dependent correlations (quantum entanglement) exist over and above the classical ones expressed in terms of probabilities. While the classical correlations are essentially local in nature, quantum correlations are shared globally in the process of environment-induced decoherence. The decoherence is an effectively random process that removes local correlations in the course of global sharing of entanglement—the removal being especially manifest in the case of systems that appear as classical ones. It is this aspect of the decoherence process that makes the so-called measurement postulate (one relating to wave function collapse) cohere with the rest of the principles of quantum theory where the latter implies a Schrodinger type time evolution of quantum mechanical systems. -/- The mathematical basis of the quantum correlations consists of the description of pure states of a system in terms of vectors in a linear vector space (a mixed state appears as an admixture of pure states with some probability distribution associated with it) and, in addition, the description of (pure) states of composite systems as vectors in the product space arising from the component sub-systems. -/- The crucial aspect of the decoherence process, of significance in the context of the apparent incompatibility of the measurement postulate with the unitary Schrodinger evolution, relates to the fact that it is almost instantaneous in the case of a classical object (one that is nevertheless amenable to a quantum description). Indeed, the decoherence time is, in all likelihood, of the order of the Planck scale, being driven by field fluctuations in the Planck regime. This points to factors of an unknown nature determining the finest details of the decoherence process since Planck scale physics remains an obscure terrain. -/- In other words, quantum theory is, to all intents and purposes, in the need of a radical revision, in keeping with the fact that all theories are defeasible and need revision as our domains of experience expand and get realigned in a complex manner. The context within which quantum theory (and quantum field theory too) is defined is set precisely by the Planck scale, across which a novel theoretical framework is likely to emerge. However, as in the case of theory revisions in general, that emerging theory will stand in an asymmetric relation of incommensurability with the present-day quantum theory, where the concepts of the latter will be comprehensible in terms of those of the former, but the converse will not hold. (shrink)

The fields of linguistic pragmatics and legal interpretation are deeply interrelated. The purpose of this paper is to show how pragmatics and the developments in argumentation theory can contribute to the debate on legal interpretation. The relation between the pragmatic maxims and the presumptions underlying the legal canons are brought to light, unveiling the principles that underlie the types of argument usually used to justify a construction. The Gricean maxims and the arguments of legal interpretation are regarded as presumptions (...) subject to default used to justify an interpretation. This approach can allow one to trace the different legal interpretive arguments back to their basic underlying presumptions, so that they can be compared, ordered, and assessed according to their defeasibility conditions. This approach allows one to understand the difference between various types of interpretive canons, and their strength in justifying an interpretation. (shrink)

Analyses of moral value judgements must meet a practicality requirement: moral speech acts characteristically express pro- or con-attitudes, indicate that speakers are motivated in certain ways, and exert influence on others' motivations. Nondescriptivists including Simon Blackburn and Allan Gibbard claim that no descriptivist analysis can satisfy this requirement. I argue first that while the practicality requirement is defeasible, it indeed demands a connection between value judgement and motivation that resembles a semantic or conceptual rather than merely contingent psychological link. I (...) then show how a form of descriptivism, the interest-relational theory, satisfies the requirement as a pragmatic and conversational feature of value judgement – thereby also accommodating its defeasibility. The word ``good'' is always indexed to some set of motivations: when this index is unarticulated in many contexts the speaker conversationally implicates possession of those motivations. (shrink)

We present two defeasible logics of norm-propositions (statements about norms) that (i) consistently allow for the possibility of normative gaps and normative conflicts, and (ii) map each premise set to a sufficiently rich consequence set. In order to meet (i), we define the logic LNP, a conflict- and gap-tolerant logic of norm-propositions capable of formalizing both normative conflicts and normative gaps within the object language. Next, we strengthen LNP within the adaptive logic framework for non-monotonic reasoning in order to meet (...) (ii). This results in the adaptive logics LNPr and LNPm, which interpret a given set of premises in such a way that normative conflicts and normative gaps are avoided ‘whenever possible’. LNPr and LNPm are equipped with a preferential semantics and a dynamic proof theory. (shrink)

Normative moral theories are frequently invoked to serve one of two distinct purposes: (1) explicate a criterion of rightness, or (2) provide an ethical decision-making procedure. Although a criterion of rightness provides a valuable theoretical ideal, proposed criteria rarely can be (nor are they intended to be) directly translated into a feasible decision-making procedure. This paper applies the computational framework of bounded rationality to moral decision-making to ask: how ought a bounded human agent make ethical decisions? We suggest agents ought (...) to follow moral maxims: principles that approximate rightness in many situations, but that can be overridden in specific, precisely describable circumstances. While this intuitive idea has been proposed many times before, we provide a precise model of how maxim consequentialism functions as an approximation to an act-consequentialist criterion of rightness, while maintaining the flexibility and defeasibility that has eluded most forms of rule consequentialism. Furthermore, while our overarching aim is to propose a new normative standard of moral decision-making, we demonstrate how maxim consequentialism can also function as a descriptive account of human behavior. We conclude by noting that different criteria of rightness may lead to different maxim-based ethics. (shrink)

School boosters are tax-exempt organizations that engage in fundraising efforts to provide public schools with supplementary resources. This paper argues that prevailing forms of school boosting are defeasibly unjust. Section 1 shows that inequalities in public education funding in the United States violate John Rawls’s two principles of domestic justice. Section 2 argues that prevailing forms of school boosting exacerbate and plausibly perpetuate these injustices. Section 3 then contends that boosting thereby defeasibly violates Rawlsian principles of nonideal theory for (...) rectifying injustice. Thus, boosting should be presumptively either made illegal or substantially reformed. Finally, Section 4 responds to potential objections. (shrink)

Inferentialism, especially Brandom’s theory, is the project aimed at understanding meaning as determined by inferences, and language as a social practice governed by rational discursive norms. Discursive practice is thus understood as the basic rational practice, where commitments undertaken by participants are evaluated in terms of their being correct/incorrect. This model of explanation is also intended to rescue, by means of reasons, the commitments we undertake ourselves and assess the commitments we attribute to others, in an objective sense: starting (...) from our subjective normative and doxastic attitudes we should be able to use the normative discursive resources apt to assess our commitments, not only referring to what we take to be correct, but also referring to how things actually are.My hypothesis is that this objectivity is not achieved only on the basis of the rational structure of discursive practice. The main worry concerns the fact that material inferences, those responsible for the content of our concepts (and commitments), are in general non-monotonic. These inferences put experts in an advantageous position,namely as those capable of defeasible reasoning. I propose a view by which this asymmetry among language users is the crucial factor in assessing the objectivity of claims within discursive practice. (shrink)

This book looks at the affective-cognitive roots of how the human mind inquires into the workings of nature and, more generally, how the mind confronts reality. Reality is an infinitely complex system, in virtue of which the mind can comprehend it only in bits and pieces, by making up interpretations of the myriads of signals received from the world by way of integrating those with information stored from the past. This constitutes a piecemeal interpretation by which we assemble our phenomenal (...) reality. In perceiving the complex world and responding to it, the mind invokes the logic of affect and the logic of reason, the former mostly innate and implicit, and the latter generated consciously in explicit terms with reference to mind-independent relations between entities in nature. It is a strange combination of affect and reason that enables us to make decisions and inferences, --- the latter mostly of the inductive type --- thereby making possible the development of theories. Theories are our tool-kits for explaining and predicting phenomena, guiding us along in our journey in life. Theories, however, are defeasible, and need to be constantly updated, at times even radically. In this, the self and the soul are of enormous relevance. The former is the affect-based psychological engine driving all our mental processes, while the latter is the capacity of the conscious mind to examine and reconstruct the self by modulating repressed conflicts. If the soul remains inoperative, all our theories become misdirected and a rot spreads inexorably all around us. (shrink)

In this paper, by suggesting a formal representation of science based on recent advances in logic-based Artificial Intelligence (AI), we show how three serious concerns around the realisation of traditional scientific realism (the theory/observation distinction, over-determination of theories by data, and theory revision) can be overcome such that traditional realism is given a new guise as ‘naturalised’. We contend that such issues can be dealt with (in the context of scientific realism) by developing a formal representation of science (...) based on the application of the following tools from Knowledge Representation: the family of Description Logics, an enrichment of classical logics via defeasible statements, and an application of the preferential interpretation of the approach to Belief Revision. (shrink)

Applying a theory of psychological modularity, I argue for a theory of defeasibility conditions for the epistemic justification of perceptual beliefs. My theory avoids the extremes of holism (e.g., coherentism and confirmation holism) and of foundationalist theories of non-inferential justification.

We propose a solution to the problem of logical omniscience in what we take to be its fundamental version: as concerning arbitrary agents and the knowledge attitude per se. Our logic of knowledge is a spin-off from a general theory of thick content, whereby the content of a sentence has two components: an intension, taking care of truth conditions; and a topic, taking care of subject matter. We present a list of plausible logical validities and invalidities for the logic (...) of knowledge per se for arbitrary agents, and isolate three explanatory factors for them: the topic-sensitivity of content; the fragmentation of knowledge states; the defeasibility of knowledge acquisition. We then present a novel dynamic epistemic logic that yields precisely the desired validities and invalidities, for which we provide expressivity and completeness results. We contrast this with related systems and address possible objections. (shrink)

An adequate semantics for generic sentences must stake out positions across a range of contested territory in philosophy and linguistics. For this reason the study of generic sentences is a venue for investigating different frameworks for understanding human rationality as manifested in linguistic phenomena such as quantification, classification of individuals under kinds, defeasible reasoning, and intensionality. Despite the wide variety of semantic theories developed for generic sentences, to date these theories have been almost universally model-theoretic and representational. This essay outlines (...) a range of proof-theoretic analyses for characterizing generics. Particular attention is given to an expressivist proof-theory that can be traced to 1) work on logical syntax that Carnap undertook prior to his turn toward truth-conditional model theory in the late 1930s, and 2) research on sequent calculi and natural deduction systems that originate in work from Gentzen and Prawitz.11 This essay offers a more precise exposition of some of the material discussed in the first two chapters of my dissertation (Stovall Citation2015a). These ideas developed in the context of a working group on non-monotonic logic run by Robert Brandom, and they were subsequently clarified through the work of Nissim Francez (particularly Francez Citation2015). I am indebted to many people for feedback and criticism on this essay, though I am sure none among them would agree with everything I say and do here. I would particularly like to thank Brandom, Francez, Ulf Hlobil, Daniel Kaplan, Jared Millson, Bernhard Nickel, Jaroslav Peregrin, Jeffry Pelletier, Thomas Ricketts, Mark Risjord, Shawn Standefer, and two reviewers for this journal. Work on this essay was supported by the joint Lead-Agency research grant between the Austrian Science Foundation (FWF) and the Czech Science Foundation (GAČR), Inferentialism and Collective Intentionality, GF17-33808L. It was substantially revised prior to its final submission. (shrink)

I argue that semantics is the study of the proprietary database of a centrally inaccessible and informationally encapsulated input–output system. This system’s role is to encode and decode partial and defeasible evidence of what speakers are saying. Since information about nonlinguistic context is therefore outside the purview of semantic processing, a sentence’s semantic value is not its content but a partial and defeasible constraint on what it can be used to say. I show how to translate this thesis into a (...) detailed compositional-semantic theory based on the influential framework of Heim and Kratzer. This approach situates semantics within an independently motivated account of human cognitive architecture and reveals the semantics–pragmatics interface to be grounded in the underlying interface between modular and central systems. (shrink)

From the early reception of Thomas Aquinas up to the present, many have interpreted his theory of liberum arbitrium to imply intellectual determinism: we do not control our choices, because we do not control the practical judgments that cause our choices. In this paper we argue instead that he rejects determinism in general and intellectual determinism in particular, which would effectively destroy liberum arbitrium as he conceives of it. We clarify that for Aquinas moral responsibility presupposes liberum arbitrium and (...) thus the ability to do otherwise, although the ability to do otherwise applies differently to praise and blame. His argument against intellectual determinism is not straightforward, but we construct it by analogy to his arguments against other deterministic threats. The non-determinism of the intellect’s causality with respect to the will results from his claims that practical reasoning is defeasible and that the reasons for actions are not contrastive reasons. (shrink)

How, if at all, is knowing how to do something defeasible? Some, the “intellectualists”, treat the defeasibility of knowledge-how as in some way derivative on the defeasibility of knowledge-that. According to a recent proposal by Carter and Navarro (Philos Phenomenol Res 3:662–685, 2017), knowledge-how defeat cannot be explained in terms of knowledge-that defeat; instead, knowledge-how defeat merits and entirely separate treatment. The thought behind “separatism” is easy to articulate. Assuming that knowledge of any kind is defeasible, since knowledge-that (...) and knowledge-how are fundamentally different beasts, the best accounts of their defeasibility must reflect the underlying differences between them. I reject a separatist treatment of the defeasibility of knowledge-that and knowledge-how. One can acknowledge certain important differences between knowledge-that and knowledge-how without thereby needing two theories of defeasibility. Ultimately, though, I’ll argue that the defeasibility of basic knowledge-how, unlike non-basic knowledge-how, is a much more difficult issue than has been acknowledged. (shrink)

In this chapter, we begin by sketching in the broadest possible strokes the ideas behind two formal systems that have been introduced with to goal of explicating the ways in which reasons interact to support the actions and conclusions they do. The first of these is the theory of defeasible reasoning developed in the seminal work of Pollock; the second is a more recent theory due to Horty, which adapts and develops the default logic introduced by Reiter to (...) provide an account of reasons. However, the implementations are complex enough, in both cases, to prevent anything more than this sketch. And we would not want to give the impression that we think that work on the logic of reasons must follow the path mapped out in either of these theories—indeed, we feel that the field is wide open. In the remainder of the chapter, therefore, will concentrate on a number of issues bearing on the logic of reasons that are either not treated in the work of Pollock and Horty, or whose treatment there is, we feel, either inadequate or incomplete. These are: first, the question of whether it is necessary to understand logical interactions among reasons themselves, rather than simply between reasons and the actions or conclusions they support, and if so, what principles might govern these interactions; second, priority relations among reasons and the notion of reason accrual; and third, some problems posed by undercutting defeat. (shrink)

Both in formal and computational natural language semantics, the classical correspondence view of meaning – and, more specifically, the view that the meaning of a declarative sentence coincides with its truth conditions – is widely held. Truth (in the world or a situation) plays the role of the given, and meaning is analysed in terms of it. Both language and the world feature in this perspective on meaning, but language users are conspicuously absent. In contrast, the inferentialist semantics that Robert (...) Brandom proposes in his magisterial book ‘Making It Explicit’ puts the language user centre stage. According to his theory of meaning, the utterance of a sentence is meaningful in as far as it is a move by a language user in a game of giving and asking for reasons (with reasons underwritten by a notion of good inferences). In this paper, I propose a proof-theoretic formalisation of the game of giving and asking for reasons that lends itself to computer implementation. In the current proposal, I flesh out an account of defeasible inferences, a variety of inferences which play a pivotal role in ordinary (and scientific) language use. (shrink)

In a recent reply to our article, “What is Interpretability?,” Prasetya argues against our position that artificial neural networks are explainable. It is claimed that our indefeasibility thesis—that adding complexity to an explanation of a phenomenon does not make the phenomenon any less explainable—is false. More precisely, Prasetya argues that unificationist explanations are defeasible to increasing complexity, and thus, we may not be able to provide such explanations of highly complex AI models. The reply highlights an important lacuna in our (...) original paper, the omission of the unificationist account of explanation, and affords us the opportunity to respond. Here, we argue that artificial neural networks are explainable in a way that should satisfy unificationists and that interpretability methods present ways in which ML theories can achieve unification. (shrink)

In this paper, we use concepts, structure and tools from argumentation theory to show how conversational implicatures are triggered by conflicts of presumptions. Presumptive implicatures are shown to be based on defeasible forms of inference used in conditions of lack of knowledge, including analogical reasoning, inference to the best explanation, practical reasoning, appeal to pity, and argument from cause. Such inferences are modelled as communicative strategies to knowledge gaps that shift the burden of providing the missing contrary evidence to (...) the other party in a dialogue. Through a series of illustrative examples, we show how such principles of inference are based on common knowledge about the ordinary course of events shared by participants in a structured dialogue setting in which they take turns putting forward and responding to speech acts. (shrink)

This paper criticizes phenomenal conservatism––the influential view according to which a subject S’s seeming that P provides S with defeasible justification for believing P. I argue that phenomenal conservatism, if true at all, has a significant limitation: seeming-based justification is elusive because S can easily lose it by just reflecting on her seemings and speculating about their causes––I call this the problem of reflective awareness. Because of this limitation, phenomenal conservatism doesn’t have all the epistemic merits attributed to it by (...) its advocates. If true, phenomenal conservatism would constitute a unified theory of epistemic justification capable of giving everyday epistemic practices a rationale, but it wouldn’t afford us the means of an effective response to the sceptic. Furthermore, phenomenal conservatism couldn’t form the general basis for foundationalism. (shrink)

This paper proposes a novel educational approach to epistemic vice rehabilitation. Its authors Gerry Dunne and Alkis Kotsonis note that, like Quassim Cassam, they remain optimistic about the possibility of improvement with regard to epistemic vice. However, unlike Cassam, who places the burden of minimizing or overcoming epistemic vices and their consequences on the individual, Dunne and Kotsonis argue that vice rehabilitation is best tackled via the exemplarist animated community of inquiry zetetic principles and defeasible-reasons-regulated deliberative processes. The vice-reduction method (...) they propose is made up of four distinct yet complementary components: (1) positive exemplarism of epistemic virtue (saints), (2) negative exemplarism of epistemic vice (sinners), (3) direct teaching/instruction, and (4) cognitive apprenticeship. Dunne and Kotsonis argue that this pedagogical intervention appropriately considers learnings deriving from forensic scrutiny of both ideal and non-ideal interpersonally calibrated zetetic features integral to knowledge acquisition as well as wider societal influences impacting the development of agents' epistemic character. It bridges research on vice epistemology (Cassam's obstructivist theory), social epistemology (corrupted social processes mitigating against vice rehabilitation), virtue epistemology, and moral exemplarism. (shrink)

I have argued that Gettier cases are misleading because, even though they appear to be cases of knowledge failure, they are in fact cases of semantic failure. Atkins has responded to my original paper and I have replied to his response. He has then responded again to insist that he has the so-called “Gettier intuition.” But he now admits that intuitions are only defeasible, not conclusive, evidence for and/or against philosophical theories. I address the implications of Atkins’ admission in this (...) paper and I again show that his attempts to revise Gettier’s original cases such that they do not involve semantic failures are unsuccessful. (shrink)

This paper makes an ethical and a conceptual case against any purported duty to come out of the closet. While there are recognizable goods associated with coming out, namely, leading an authentic life and resisting oppression, these goods generate a set of imperfect duties that are defeasible in a wide range of circumstances, and are only sometimes fulfilled by coming out. Second, practices of coming out depend on a ‘lump’ picture of sexuality and on an insufficiently subtle account of responsible (...) disclosure. We value and promote the goods of out best when we leave the framework of the closet, and not merely the closet door, behind. (shrink)