Blackwell Companion for the Philosophy of Language (Second Edition), 2015
This article offers an overview of inferential role semantics. We aim to provide a
map of the te... more This article offers an overview of inferential role semantics. We aim to provide a
map of the terrain as well as challenging some of the inferentialist’s standard commitments. We begin by introducing inferentialism and placing it into the wider context of contemporary philosophy of language. §2 focuses on what is standardly considered both the most important test case for and the most natural application of inferential role semantics: the case of the logical constants. We discuss some of the (alleged) benefits of logical inferentialism, chiefly with regards to the epistemology of logic, and consider a number of objections. §3 introduces and critically examines the most influential and most fully developed form of global inferentialism: Robert Brandom’s inferentialism about linguistic and conceptual content in general. Finally, in §4 we consider a number of general objections to IRS and consider possible responses on the inferentialist’s behalf.
Epistemic utility theory (EUT) is generally coupled with \emph{veritism}. Veritism is the view t... more Epistemic utility theory (EUT) is generally coupled with \emph{veritism}. Veritism is the view that truth is the sole fundamental epistemic value. Veritism, when paired with EUT, entails a methodological commitment: Norms of epistemic rationality are justified only if they can be derived from considerations of accuracy alone. According to EUT, then, believing truly has epistemic value, while believing falsely has epistemic disvalue. This raises the question as to how the rational believer should balance the prospect of true belief against the risk of error. A strong intuitive case can be made for a kind of epistemic \emph{conservatism}---that we should disvalue error more than we value true belief. I argue that none of the ways in which advocates of veritist EUT have sought to motivate conservatism can be squared with their methodological commitments. Short of any such justification, they must therefore either abandon their most central methodological principle or else adopt a permissive line with respect to epistemic risk.
Rough draft. To appear in Knauff, M. and Spohn, W. (ed.), Handbook of Rationality, MIT Press.
This chapter addresses the question as to how (if at all) propositional (PL) and first-order logi... more This chapter addresses the question as to how (if at all) propositional (PL) and first-order logic (FOL) relate to epistemic rationality. Rationality, it is often held, demands that our attitudes cohere in particular ways. Logic is often invoked as a source of such coherence requirements when it comes to belief: An ideally rational agent's beliefs are consistent and closed under logical consequence. However, this traditional picture has been challenged from various quarters. We begin by briefly reviewing the key concepts involved in PL and FOL. We then critically examine two distinct approaches to justifying logic-based requirements of rationality. The first lays down a set of desiderata codifying our intuitions, and then seeks to formulate a principle articulating the link between logic and rational belief that satisfies them. The second starts by identifying our most fundamental epistemic aim and seeks to derive requirements of rationality based on their ability to promote this aim.
This paper explores an apparent tension between two widely held views about logic: that logic is ... more This paper explores an apparent tension between two widely held views about logic: that logic is normative and that there are multiple equally legitimate logics. The tension is this. If logic is normative, it tells us something about how we ought to reason. If, as the pluralist would have it, there are several correct logics, those logics make incompatible recommendations as to how we ought to reason. But then which of these logics should we look to for normative guidance? I argue that inasmuch as pluralism draws its motivation from its ability to defuse logical disputes—that is, disputes between advocates of rival logics—it is unable to provide an answer: pluralism collapses into monism with respect to either the strongest or the weakest admissible logic.
[The original paper that went by this title was split into three parts. This is one of them]
Logi... more [The original paper that went by this title was split into three parts. This is one of them] Logic, the tradition has it, is normative for reasoning. Famously, the tradition was challenged by Gilbert Harman who argued that there is no interesting general link between 'facts' about logical consequence and norms of belief formation and revision. A number of authors (including John MacFarlane and Hartry Field) have sought to rehabilitate the traditional view of the normative status of logic against Harman. In this paper, I argue that the debate as a whole is marred by a failure of the disputing parties to distinguish three different types of normative assessment, and hence three distinct ways in which the question of the normativity of logic might be understood. Logical principles might be thought to provide first-personal directives to the reasoning agent, they might be thought to serve as third-personal evaluative standards, or they might underwrite our third-personal appraisals of others whereby be attribute praise and blame. I characterize the three normative functions in general terms. I then show how a failure to appreciate this threefold distinction has impeded progress since it has led the participants in the debate to talk past one another. Moreover, I show how the distinction paves the way for a more fruitful engagement with the issue.
Logic, the tradition has it, is normative for reasoning. But is that really so? And if so, in wha... more Logic, the tradition has it, is normative for reasoning. But is that really so? And if so, in what sense is logic normative for reasoning? As Gilbert Harman has reminded us, devising a logic and devising a theory of reasoning are two separate enterprises. Hence, logic's normative authority cannot reside in the fact that principles of logic just are norms of reasoning. Once we cease to identify the two, we are left with a gap. To bridge the gap one would need to produce what John MacFarlane has appropriately called a bridge principle, i.e. a general principle articulating a substantive and systematic link between logical entailment and norms of reasoning. This is Harman's skeptical challenge. In this paper I argue that Harman's skeptical challenge can be met. I show how candidate bridge principles can be systematically generated and evaluated against a set of well-motivated desiderata. Moreover, I argue that bridge principles advanced by MacFarlane himself and others, for all their merit, fail to address the problem originally set forth by Harman and so do not meet the skeptical challenge. Finally, I develop a bridge principle that meets Harman's requirements as well as being substantive.
This is a survey paper in German covering a number of central themes in the philosophy of logic, ... more This is a survey paper in German covering a number of central themes in the philosophy of logic, including the debates surrounding the notion of logical consequence, the problem of demarcating logic, logical pluralism vs. logical monism and the question of the normativity of logic.
In this paper I examine a neglected question concerning the centerpiece of Carnap's philosophy: t... more In this paper I examine a neglected question concerning the centerpiece of Carnap's philosophy: the principle of tolerance. The principle of tolerance states that we are free to devise and adopt any well-defined form of language or linguistic framework we please. A linguistic framework defines framework-internal standards of correct reasoning that guide is in our first-order scientific pursuits. The choice of a linguistic framework, on the other hand, is an `external' question to be settled on pragmatic grounds and so not itself constrained by these (framework-internal) standards. However, even if choosing a framework is a practical matter, we would nevertheless expect the process of framework selection to be subject to rational norms. But which norms might those be? And where do they come from? I begin by showing that these questions are crucial to the success of Carnap's entire philosophical project. I then offer a response on behalf of the Carnapian which guarantees the rationality of the process of framework selection, while remaining true to Carnap's firm commitment to tolerance.
Logic has traditionally been construed as a normative discipline; it sets forth standards of corr... more Logic has traditionally been construed as a normative discipline; it sets forth standards of correct reasoning. Explosion is a valid principle of classical logic. It states that an inconsistent set of propositions entails any proposition whatsoever. However, ordinary agents presumably do---occasionally, at least---have inconsistent belief sets. Yet it is false that such agents may, let alone ought, to believe any proposition they please. Therefore, our logic should not recognize explosion as a logical law. Call this the `normative argument against explosion'. Arguments of this type play---implicitly or explicitly---a central role in motivating paraconsistent logics. Branden Fitelson (2008), in a throwaway remark, has conjectured that there is no plausible 'bridge principle' articulating the normative link between logic and reasoning capable of supporting such arguments. This paper offers a critical evaluation of Fitelson's conjecture and hence of normative arguments for paraconsistency and the conceptions of logic's normative status on which they repose. It is argued that Fitelson's conjecture turns out to be correct: normative arguments for paraconsistency probably fail.
In a series of recent papers, Corine Besson argues that dispositionalist accounts of logical know... more In a series of recent papers, Corine Besson argues that dispositionalist accounts of logical knowledge conflict with ordinary reasoning. She cites cases in which, rather than applying a logical principle to deduce certain implications of our antecedent beliefs, we revise some of those beliefs in the light of their unpalatable consequences. She argues that such instances of, in Gilbert Harman’s phrase, ‘reasoned change in view’ cannot be accommodated by the dispositionalist approach, and that we would do well to conceive of logical knowledge as a species of propositional knowledge instead. In this paper, we propose a dispositional account that is more general than the one Besson considers, viz. one that does not merely apply to beliefs, and claim that dispositionalists have the resources to account for reasoned change in view. We then raise what we take to be more serious challenges for the dispositionalist view, and sketch some lines of response dispositionalists might offer.
The requirement of proof-theoretic harmony has played a pivotal role in a number of debates in th... more The requirement of proof-theoretic harmony has played a pivotal role in a number of debates in the philosophy of logic. Different authors have attempted to precisify the notion in different ways. Among these, three proposals have been prominent in the literature: Harmony-as-conservative extension, Harmony-as-levelling procedure and Tennant’s Harmony-as-deductive equilibrium. In this paper I propose to clarify the logical relationships between these accounts. In particular, I demon- strate that what I call the equivalence conjecture—that these three notions essentially come to the same thing—is erroneous.
The notion of harmony has played a pivotal role in a number of debates in the philosophy of logic... more The notion of harmony has played a pivotal role in a number of debates in the philosophy of logic. Yet there is little agreement as to how the requirement of harmony should be spelled out in detail or even what purpose it is to serve. Most if not all conceptions of harmony can already be found in Michael Dummett’s seminal discussion of the matter in The Logical Basis of Metaphysics. Hence, if we wish to gain a better understanding of the notion of harmony, we do well to start here. Unfortunately, however, Dummett’s discussion is not always easy to follow. The following is an attempt to disentangle the main strands of Dummett’s treatment of harmony. The different variants of harmony as well as their interrelations are clarified and their individual shortcomings qua interpretations of harmony are demonstrated. Though no attempt is made to give a detailed alternative account of harmony here, it is hoped that our discussion will lay the ground for an adequate rigorous treatment of this central notion.
This paper argues that logical inferentialists should reject multiple-conclusion logics. Logical ... more This paper argues that logical inferentialists should reject multiple-conclusion logics. Logical inferentialism is the position that the meanings of the logical constants are determined by the rules of inference they obey. As such, logical inferentialism requires a proof-theoretic framework within which to operate. However, in order to fulfil its semantic duties, a deductive system has to be suitably connected to our inferential practices. I argue that, contrary to an established tradition, multiple-conclusion systems are ill-suited for this purpose because they fail to provide a 'natural' representation of our ordinary modes of inference. Moreover, the two most plausible attempts at bringing multiple conclusions into line with our ordinary forms of reasoning, the disjunctive reading and the bilateralist denial interpretation, are unacceptable by inferentialist standards.
Blackwell Companion for the Philosophy of Language (Second Edition), 2015
This article offers an overview of inferential role semantics. We aim to provide a
map of the te... more This article offers an overview of inferential role semantics. We aim to provide a
map of the terrain as well as challenging some of the inferentialist’s standard commitments. We begin by introducing inferentialism and placing it into the wider context of contemporary philosophy of language. §2 focuses on what is standardly considered both the most important test case for and the most natural application of inferential role semantics: the case of the logical constants. We discuss some of the (alleged) benefits of logical inferentialism, chiefly with regards to the epistemology of logic, and consider a number of objections. §3 introduces and critically examines the most influential and most fully developed form of global inferentialism: Robert Brandom’s inferentialism about linguistic and conceptual content in general. Finally, in §4 we consider a number of general objections to IRS and consider possible responses on the inferentialist’s behalf.
Epistemic utility theory (EUT) is generally coupled with \emph{veritism}. Veritism is the view t... more Epistemic utility theory (EUT) is generally coupled with \emph{veritism}. Veritism is the view that truth is the sole fundamental epistemic value. Veritism, when paired with EUT, entails a methodological commitment: Norms of epistemic rationality are justified only if they can be derived from considerations of accuracy alone. According to EUT, then, believing truly has epistemic value, while believing falsely has epistemic disvalue. This raises the question as to how the rational believer should balance the prospect of true belief against the risk of error. A strong intuitive case can be made for a kind of epistemic \emph{conservatism}---that we should disvalue error more than we value true belief. I argue that none of the ways in which advocates of veritist EUT have sought to motivate conservatism can be squared with their methodological commitments. Short of any such justification, they must therefore either abandon their most central methodological principle or else adopt a permissive line with respect to epistemic risk.
Rough draft. To appear in Knauff, M. and Spohn, W. (ed.), Handbook of Rationality, MIT Press.
This chapter addresses the question as to how (if at all) propositional (PL) and first-order logi... more This chapter addresses the question as to how (if at all) propositional (PL) and first-order logic (FOL) relate to epistemic rationality. Rationality, it is often held, demands that our attitudes cohere in particular ways. Logic is often invoked as a source of such coherence requirements when it comes to belief: An ideally rational agent's beliefs are consistent and closed under logical consequence. However, this traditional picture has been challenged from various quarters. We begin by briefly reviewing the key concepts involved in PL and FOL. We then critically examine two distinct approaches to justifying logic-based requirements of rationality. The first lays down a set of desiderata codifying our intuitions, and then seeks to formulate a principle articulating the link between logic and rational belief that satisfies them. The second starts by identifying our most fundamental epistemic aim and seeks to derive requirements of rationality based on their ability to promote this aim.
This paper explores an apparent tension between two widely held views about logic: that logic is ... more This paper explores an apparent tension between two widely held views about logic: that logic is normative and that there are multiple equally legitimate logics. The tension is this. If logic is normative, it tells us something about how we ought to reason. If, as the pluralist would have it, there are several correct logics, those logics make incompatible recommendations as to how we ought to reason. But then which of these logics should we look to for normative guidance? I argue that inasmuch as pluralism draws its motivation from its ability to defuse logical disputes—that is, disputes between advocates of rival logics—it is unable to provide an answer: pluralism collapses into monism with respect to either the strongest or the weakest admissible logic.
[The original paper that went by this title was split into three parts. This is one of them]
Logi... more [The original paper that went by this title was split into three parts. This is one of them] Logic, the tradition has it, is normative for reasoning. Famously, the tradition was challenged by Gilbert Harman who argued that there is no interesting general link between 'facts' about logical consequence and norms of belief formation and revision. A number of authors (including John MacFarlane and Hartry Field) have sought to rehabilitate the traditional view of the normative status of logic against Harman. In this paper, I argue that the debate as a whole is marred by a failure of the disputing parties to distinguish three different types of normative assessment, and hence three distinct ways in which the question of the normativity of logic might be understood. Logical principles might be thought to provide first-personal directives to the reasoning agent, they might be thought to serve as third-personal evaluative standards, or they might underwrite our third-personal appraisals of others whereby be attribute praise and blame. I characterize the three normative functions in general terms. I then show how a failure to appreciate this threefold distinction has impeded progress since it has led the participants in the debate to talk past one another. Moreover, I show how the distinction paves the way for a more fruitful engagement with the issue.
Logic, the tradition has it, is normative for reasoning. But is that really so? And if so, in wha... more Logic, the tradition has it, is normative for reasoning. But is that really so? And if so, in what sense is logic normative for reasoning? As Gilbert Harman has reminded us, devising a logic and devising a theory of reasoning are two separate enterprises. Hence, logic's normative authority cannot reside in the fact that principles of logic just are norms of reasoning. Once we cease to identify the two, we are left with a gap. To bridge the gap one would need to produce what John MacFarlane has appropriately called a bridge principle, i.e. a general principle articulating a substantive and systematic link between logical entailment and norms of reasoning. This is Harman's skeptical challenge. In this paper I argue that Harman's skeptical challenge can be met. I show how candidate bridge principles can be systematically generated and evaluated against a set of well-motivated desiderata. Moreover, I argue that bridge principles advanced by MacFarlane himself and others, for all their merit, fail to address the problem originally set forth by Harman and so do not meet the skeptical challenge. Finally, I develop a bridge principle that meets Harman's requirements as well as being substantive.
This is a survey paper in German covering a number of central themes in the philosophy of logic, ... more This is a survey paper in German covering a number of central themes in the philosophy of logic, including the debates surrounding the notion of logical consequence, the problem of demarcating logic, logical pluralism vs. logical monism and the question of the normativity of logic.
In this paper I examine a neglected question concerning the centerpiece of Carnap's philosophy: t... more In this paper I examine a neglected question concerning the centerpiece of Carnap's philosophy: the principle of tolerance. The principle of tolerance states that we are free to devise and adopt any well-defined form of language or linguistic framework we please. A linguistic framework defines framework-internal standards of correct reasoning that guide is in our first-order scientific pursuits. The choice of a linguistic framework, on the other hand, is an `external' question to be settled on pragmatic grounds and so not itself constrained by these (framework-internal) standards. However, even if choosing a framework is a practical matter, we would nevertheless expect the process of framework selection to be subject to rational norms. But which norms might those be? And where do they come from? I begin by showing that these questions are crucial to the success of Carnap's entire philosophical project. I then offer a response on behalf of the Carnapian which guarantees the rationality of the process of framework selection, while remaining true to Carnap's firm commitment to tolerance.
Logic has traditionally been construed as a normative discipline; it sets forth standards of corr... more Logic has traditionally been construed as a normative discipline; it sets forth standards of correct reasoning. Explosion is a valid principle of classical logic. It states that an inconsistent set of propositions entails any proposition whatsoever. However, ordinary agents presumably do---occasionally, at least---have inconsistent belief sets. Yet it is false that such agents may, let alone ought, to believe any proposition they please. Therefore, our logic should not recognize explosion as a logical law. Call this the `normative argument against explosion'. Arguments of this type play---implicitly or explicitly---a central role in motivating paraconsistent logics. Branden Fitelson (2008), in a throwaway remark, has conjectured that there is no plausible 'bridge principle' articulating the normative link between logic and reasoning capable of supporting such arguments. This paper offers a critical evaluation of Fitelson's conjecture and hence of normative arguments for paraconsistency and the conceptions of logic's normative status on which they repose. It is argued that Fitelson's conjecture turns out to be correct: normative arguments for paraconsistency probably fail.
In a series of recent papers, Corine Besson argues that dispositionalist accounts of logical know... more In a series of recent papers, Corine Besson argues that dispositionalist accounts of logical knowledge conflict with ordinary reasoning. She cites cases in which, rather than applying a logical principle to deduce certain implications of our antecedent beliefs, we revise some of those beliefs in the light of their unpalatable consequences. She argues that such instances of, in Gilbert Harman’s phrase, ‘reasoned change in view’ cannot be accommodated by the dispositionalist approach, and that we would do well to conceive of logical knowledge as a species of propositional knowledge instead. In this paper, we propose a dispositional account that is more general than the one Besson considers, viz. one that does not merely apply to beliefs, and claim that dispositionalists have the resources to account for reasoned change in view. We then raise what we take to be more serious challenges for the dispositionalist view, and sketch some lines of response dispositionalists might offer.
The requirement of proof-theoretic harmony has played a pivotal role in a number of debates in th... more The requirement of proof-theoretic harmony has played a pivotal role in a number of debates in the philosophy of logic. Different authors have attempted to precisify the notion in different ways. Among these, three proposals have been prominent in the literature: Harmony-as-conservative extension, Harmony-as-levelling procedure and Tennant’s Harmony-as-deductive equilibrium. In this paper I propose to clarify the logical relationships between these accounts. In particular, I demon- strate that what I call the equivalence conjecture—that these three notions essentially come to the same thing—is erroneous.
The notion of harmony has played a pivotal role in a number of debates in the philosophy of logic... more The notion of harmony has played a pivotal role in a number of debates in the philosophy of logic. Yet there is little agreement as to how the requirement of harmony should be spelled out in detail or even what purpose it is to serve. Most if not all conceptions of harmony can already be found in Michael Dummett’s seminal discussion of the matter in The Logical Basis of Metaphysics. Hence, if we wish to gain a better understanding of the notion of harmony, we do well to start here. Unfortunately, however, Dummett’s discussion is not always easy to follow. The following is an attempt to disentangle the main strands of Dummett’s treatment of harmony. The different variants of harmony as well as their interrelations are clarified and their individual shortcomings qua interpretations of harmony are demonstrated. Though no attempt is made to give a detailed alternative account of harmony here, it is hoped that our discussion will lay the ground for an adequate rigorous treatment of this central notion.
This paper argues that logical inferentialists should reject multiple-conclusion logics. Logical ... more This paper argues that logical inferentialists should reject multiple-conclusion logics. Logical inferentialism is the position that the meanings of the logical constants are determined by the rules of inference they obey. As such, logical inferentialism requires a proof-theoretic framework within which to operate. However, in order to fulfil its semantic duties, a deductive system has to be suitably connected to our inferential practices. I argue that, contrary to an established tradition, multiple-conclusion systems are ill-suited for this purpose because they fail to provide a 'natural' representation of our ordinary modes of inference. Moreover, the two most plausible attempts at bringing multiple conclusions into line with our ordinary forms of reasoning, the disjunctive reading and the bilateralist denial interpretation, are unacceptable by inferentialist standards.
My thesis is an attempt to supply answers to what I take to be the three central questions facing... more My thesis is an attempt to supply answers to what I take to be the three central questions facing inferentialism about the logical constants (which I call logical inferentialism). What are the assumptions about meaning that underpin logical inferentialism? What is the correct formulation of the principle of harmony? And finally: What follows from logical inferentialism? Accordingly, the dissertation falls into three parts.
I begin by laying out the fundamental meaning-theoretic principles that underpin logical inferentialism: it is use-theoretic; it subscribes to the two-aspect theory of meaning; as the name makes plain, it is inferentialist in approach; and it is committed to a weak form of molecularism. Having spelled out its founding assumptions, I defend inferentialism against the charge that, contrary to its defining motto, the meanings of the logical operators are not fully determined by the rules of inference they obey, but also in part by structural assumptions.
The second part offers a comprehensive treatment of the notion of harmony. After giving an analysis of the notion, I review and criticize existing accounts of harmony in the literature. In particular, I show that Michael Dummett’s and Stephen Read’s theories are unsatisfactory and I present a counterexample to Neil Tennant’s principle of harmony. I then advance my own version of harmony, which not only avoids the difficulties that plagued the accounts mentioned, but also boasts additional advantageous features.
In the final part I examine the consequences of these results for so-called proof-theoretic arguments. Such arguments purport to show that the principle of harmony supports broadly intuitionistic revisions of our logic. I argue that, given our inferentialist commit- ments, a defence of classical logic based on the adoption of multiple-conclusion sequent calculi is misguided. Multiple-conclusion systems, I submit, are illegitimate from an in- ferentialist point of view. Moreover, I defend the principle of separability against realist attacks.
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Papers by Florian Steinberger
map of the terrain as well as challenging some of the inferentialist’s standard commitments. We begin by introducing inferentialism and placing it into the wider context of contemporary philosophy of language. §2 focuses on what is standardly considered both the most important test case for and the most natural application of inferential role semantics: the case of the logical constants. We discuss some of the (alleged) benefits of logical inferentialism, chiefly with regards to the epistemology of logic, and consider a number of objections. §3 introduces and critically examines the most influential and most fully developed form of global inferentialism: Robert Brandom’s inferentialism about linguistic and conceptual content in general. Finally, in §4 we consider a number of general objections to IRS and consider possible responses on the inferentialist’s behalf.
Logic, the tradition has it, is normative for reasoning. Famously, the tradition was challenged by Gilbert Harman who argued that there is no interesting general link between 'facts' about logical consequence and norms of belief formation and revision. A number of authors (including John MacFarlane and Hartry Field) have sought to rehabilitate the traditional view of the normative status of logic against Harman. In this paper, I argue that the debate as a whole is marred by a failure of the disputing parties to distinguish three different types of normative assessment, and hence three distinct ways in which the question of the normativity of logic might be understood. Logical principles might be thought to provide first-personal directives to the reasoning agent, they might be thought to serve as third-personal evaluative standards, or they might underwrite our third-personal appraisals of others whereby be attribute praise and blame. I characterize the three normative functions in general terms. I then show how a failure to appreciate this threefold distinction has impeded progress since it has led the participants in the debate to talk past one another. Moreover, I show how the distinction paves the way for a more fruitful engagement with the issue.
map of the terrain as well as challenging some of the inferentialist’s standard commitments. We begin by introducing inferentialism and placing it into the wider context of contemporary philosophy of language. §2 focuses on what is standardly considered both the most important test case for and the most natural application of inferential role semantics: the case of the logical constants. We discuss some of the (alleged) benefits of logical inferentialism, chiefly with regards to the epistemology of logic, and consider a number of objections. §3 introduces and critically examines the most influential and most fully developed form of global inferentialism: Robert Brandom’s inferentialism about linguistic and conceptual content in general. Finally, in §4 we consider a number of general objections to IRS and consider possible responses on the inferentialist’s behalf.
Logic, the tradition has it, is normative for reasoning. Famously, the tradition was challenged by Gilbert Harman who argued that there is no interesting general link between 'facts' about logical consequence and norms of belief formation and revision. A number of authors (including John MacFarlane and Hartry Field) have sought to rehabilitate the traditional view of the normative status of logic against Harman. In this paper, I argue that the debate as a whole is marred by a failure of the disputing parties to distinguish three different types of normative assessment, and hence three distinct ways in which the question of the normativity of logic might be understood. Logical principles might be thought to provide first-personal directives to the reasoning agent, they might be thought to serve as third-personal evaluative standards, or they might underwrite our third-personal appraisals of others whereby be attribute praise and blame. I characterize the three normative functions in general terms. I then show how a failure to appreciate this threefold distinction has impeded progress since it has led the participants in the debate to talk past one another. Moreover, I show how the distinction paves the way for a more fruitful engagement with the issue.
I begin by laying out the fundamental meaning-theoretic principles that underpin logical inferentialism: it is use-theoretic; it subscribes to the two-aspect theory of meaning; as the name makes plain, it is inferentialist in approach; and it is committed to a weak form of molecularism. Having spelled out its founding assumptions, I defend inferentialism against the charge that, contrary to its defining motto, the meanings of the logical operators are not fully determined by the rules of inference they obey, but also in part by structural assumptions.
The second part offers a comprehensive treatment of the notion of harmony. After giving an analysis of the notion, I review and criticize existing accounts of harmony in the literature. In particular, I show that Michael Dummett’s and Stephen Read’s theories are unsatisfactory and I present a counterexample to Neil Tennant’s principle of harmony. I then advance my own version of harmony, which not only avoids the difficulties that plagued the accounts mentioned, but also boasts additional advantageous features.
In the final part I examine the consequences of these results for so-called proof-theoretic arguments. Such arguments purport to show that the principle of harmony supports broadly intuitionistic revisions of our logic. I argue that, given our inferentialist commit- ments, a defence of classical logic based on the adoption of multiple-conclusion sequent calculi is misguided. Multiple-conclusion systems, I submit, are illegitimate from an in- ferentialist point of view. Moreover, I defend the principle of separability against realist attacks.