工具理性：對理由導向的窄域理性觀辯護

Abstract

本文探討工具理性的規範結構，聚焦於【寬域版本】與【窄域版本】的理論分歧。透過語義分析、邏輯形式與規範性評估，本文主張：【寬域版本】雖具有形式一致性優勢，卻無法說明不被允許的修正、缺乏實踐導向性，且削弱對理性錯誤的批評力。相對地，【窄域版本】能更清楚捕捉理由與態度之間的規範連結，並在語義與邏輯層面上展現穩定結構。本文結合模態語義學與動態邏輯資源，建構一套以理由為核心的理性觀，並回應「拔靴自助」問題。最終提出修正型的【窄域版本】，兼顧結構一致性與理由回應，提供更具說服力的工具理性理論。

This paper examines the normative structure of instrumental rationality by evaluating the theoretical disagreement between wide-scope and narrow-scope accounts. Through semantic analysis, formal logic, and normative assessment, I argue that while the wide-scope view emphasizes consistency among attitudes, it fails to explain why certain revisions are impermissible, lacks practical guidance, and undermines the evaluative force of rational criticism. In contrast, the narrow-scope view more clearly captures the normative connection between reasons and attitudes, and proves to be semantically and logically more stable. Drawing on tools from modal semantics and dynamic logic, this paper defends a reasons-based account of rationality that avoids the bootstrapping problem. I ultimately propose a revised narrow-scope formulation that integrates structural coherence with responsiveness to reasons, offering a more compelling theory of instrumental rationality.