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Volume 6, Issue 2 (2026)
3 2026, 6(2): 141-159 |
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Received: 2026/02/2 | Accepted: 2026/03/16 | Published: 2026/04/5
Received: 2026/02/2 | Accepted: 2026/03/16 | Published: 2026/04/5
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Panahi S, Kalantari S, Karbasizadeh A. A Solution for the Harman–MacFarlane Dispute Based on Steinberger’s Three Normative Roles of Logic. 3 2026; 6 (2) :141-159
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1- Department of Philosophy, Faculty of Literature and Humanities, University of Isfahan, Isfahan, Iran
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The normativity of logic is a fundamental topic in contemporary philosophy of logic and epistemology that has attracted considerable attention in the philosophical literature [Harman, 1984; Harman, 1986; MacFarlane, 2002; MacFarlane, 2004; Field, 2009a; Field, 2009b; Field, 2015; Dutilh Novaes, 2015; Steinberger, 2017a; Steinberger, 2017b; Steinberger, 2019; Russell, 2020; Evershed, 2021]. This theory addresses the central question of whether logic is merely a tool for assessing the validity of formal arguments or also plays a normative role in organizing beliefs and guiding everyday reasoning. Advocates of this view, including Gottlob Frege and John MacFarlane, regard logic as a normative discipline that, like ethics, provides binding rules for thinking [Frege, 1956; Frege, 1979; MacFarlane, 2002; MacFarlane, 2004]. According to this perspective, logic not only analyzes relations among propositions but also furnishes criteria for evaluating and guiding actual reasoning, thereby playing a direct role in the formation and revision of beliefs. In contrast, critics such as Gilbert Harman reject this view and treat logic as concerned solely with relations among propositions, which, in their view, bear no direct normative influence on everyday reasoning or belief revision [Harman, 1984; Harman, 1986]. He has shown that some normative formulations proposed by advocates, particularly MacFarlane, are practically insufficient, and unqualified acceptance of logical consequences can lead to irrational behavior. This disagreement has generated a central dispute in contemporary philosophy, primarily concerning whether and how logical principles can play a normative role in everyday reasoning. Steinberger, by distinguishing three normative roles for logic—the directive, evaluative, and appraisal roles—provides a new perspective on understanding and reconstructing this dispute [Steinberger, 2019]. Accordingly, the focus here is on analyzing the role that differing interpretations of the normativity of logic play in shaping and sustaining these disputes. Prior presuppositions, including the distinction between propositions and beliefs, differences between everyday reasoning and formal proof, the normative aim of logic, and non-commitment to any specific logical system, are assumed throughout this discussion [Steinberger, 2017a; Kalantari, 2018; Panahi et al., 2026].
The "bridge principle" is a general principle that formulates a normative connection between logical consequence and the organization of beliefs within a belief network. MacFarlane (2004) was the first to introduce this term and aimed to identify defensible principles that both establish a normative link between logic and everyday reasoning and withstand the critiques of opponents such as Harman. He provides a systematic framework employing normative concepts such as “ought,” “permissibility,” and “having a reason,” while also considering the scope of operators (narrow, medium, wide), the polarity of norms (positive and negative), and the addition of an epistemic operator (k), resulting in multiple formulations of the bridge principle. According to this framework, thirty-six formulations can be derived, only some of which are defensible against critical objections. This analytical structure allows for a systematic examination of the connection between logic and reasoning norms in everyday language and demonstrates that bridge principles can establish the link between logical consequence and everyday beliefs, leaving some norms as defensible versions.
In his critique of the normativity of logic, Harman challenges certain formulations of the bridge principle, includingCo + Wo + Wo Wr Wo - Wr +
Steinberger’s introduction of three distinct normative roles for logic—the directive, evaluative, and appraisal roles—allows for a more precise analysis of the Harman–MacFarlane dispute [Steinberger, 2019]. The normativity of logic requires a clear specification of its distinct roles because conflating them, especially in this dispute, has hindered the formulation of a defensible bridge principle. Steinberger illustrates this distinction with an action-based utilitarian example in ethics, showing that a norm can function as a directive for the agent, an evaluative measure for assessing an action, or a basis for the appraisal and attribution of praise or blame. Many existing debates arise from conflating these three roles, and respecting this distinction enables progress in the discussion of logic's normativity.
Finally, the paper revisits and revises MacFarlane’s position in response to Harman’s criticisms, showing that their dispute is largely verbal. Harman interprets norms from the perspective of directives, whereas MacFarlane interprets them from the perspective of evaluation; hence, MacFarlane’s original responses appear insufficient. Nevertheless, by modifying the formulation of the bridge principles and discarding the priority question, a new interpretation of MacFarlane’s theory emerges that can adequately address Harman’s critiques. In this reinterpretation, the premises of the bridge principles are divided into three levels with the addition of the γ operator: Directive (D E A
Accordingly, revising MacFarlane’s position in light of the three normative roles opens a new horizon for responding to Harman’s challenges and advancing the debate on the normativity of logic. By discarding the priority question and reinterpreting the premises of the bridge principles from the evaluative to the directive level—incorporating the “best estimate” operator—a revised version of the bridge principles emerges that can respond to Harman’s criticisms. In this framework, the revised normsWr + d Wo - d Wr + d Wo - d
The "bridge principle" is a general principle that formulates a normative connection between logical consequence and the organization of beliefs within a belief network. MacFarlane (2004) was the first to introduce this term and aimed to identify defensible principles that both establish a normative link between logic and everyday reasoning and withstand the critiques of opponents such as Harman. He provides a systematic framework employing normative concepts such as “ought,” “permissibility,” and “having a reason,” while also considering the scope of operators (narrow, medium, wide), the polarity of norms (positive and negative), and the addition of an epistemic operator (k), resulting in multiple formulations of the bridge principle. According to this framework, thirty-six formulations can be derived, only some of which are defensible against critical objections. This analytical structure allows for a systematic examination of the connection between logic and reasoning norms in everyday language and demonstrates that bridge principles can establish the link between logical consequence and everyday beliefs, leaving some norms as defensible versions.
In his critique of the normativity of logic, Harman challenges certain formulations of the bridge principle, including
Steinberger’s introduction of three distinct normative roles for logic—the directive, evaluative, and appraisal roles—allows for a more precise analysis of the Harman–MacFarlane dispute [Steinberger, 2019]. The normativity of logic requires a clear specification of its distinct roles because conflating them, especially in this dispute, has hindered the formulation of a defensible bridge principle. Steinberger illustrates this distinction with an action-based utilitarian example in ethics, showing that a norm can function as a directive for the agent, an evaluative measure for assessing an action, or a basis for the appraisal and attribution of praise or blame. Many existing debates arise from conflating these three roles, and respecting this distinction enables progress in the discussion of logic's normativity.
Finally, the paper revisits and revises MacFarlane’s position in response to Harman’s criticisms, showing that their dispute is largely verbal. Harman interprets norms from the perspective of directives, whereas MacFarlane interprets them from the perspective of evaluation; hence, MacFarlane’s original responses appear insufficient. Nevertheless, by modifying the formulation of the bridge principles and discarding the priority question, a new interpretation of MacFarlane’s theory emerges that can adequately address Harman’s critiques. In this reinterpretation, the premises of the bridge principles are divided into three levels with the addition of the γ operator: Directive (
Accordingly, revising MacFarlane’s position in light of the three normative roles opens a new horizon for responding to Harman’s challenges and advancing the debate on the normativity of logic. By discarding the priority question and reinterpreting the premises of the bridge principles from the evaluative to the directive level—incorporating the “best estimate” operator—a revised version of the bridge principles emerges that can respond to Harman’s criticisms. In this framework, the revised norms
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