Jusletter IT

Visualization of Hajime Yoshino’s Logical Jurisprudence

  • Authors: Vytautas Čyras / Friedrich Lachmayer
  • Category: Articles
  • Region: Austria
  • Field of law: Legal Theory
  • Collection: Conference Proceedings IRIS 2017, Peer Reviewed – Jury LexisNexis Best Paper Award of IRIS2017
  • Citation: Vytautas Čyras / Friedrich Lachmayer, Visualization of Hajime Yoshino’s Logical Jurisprudence, in: Jusletter IT 23 February 2017
Hajime Yoshino’s Logical Jurisprudence (LJ) is an important concept in legal informatics. Yoshino aims for a logic-based systematization in the legal domain. He focuses on legal reasoning and systematization. Inevitably, embracing law as a whole brings us to Hans Kelsen’s Pure Theory of Law. In sum, three issues are important in LJ: logic, Kelsen and legal informatics. In this paper we aim to visualize the architecture of LJ. We suggest expanding this with legal ontologies and words. The granularity of word-phrase-sentence-text is about different methods which apply to different units.

Table of contents

  • 1. Introduction
  • 2. Introducing Yoshino’s Logical Jurisprudence
  • 3. Logical Jurisprudence
  • 3.1. Legal Sentences
  • 3.2. Three Primitives: Legal Sentence, Validity and Inference Rule
  • 3.2.1. Connections of Legal Sentences
  • 3.2.1.1. Connector ‘and’
  • 3.2.1.2. Connection into a Legal Complex Sentence
  • 3.2.1.3. Connection between Legal Object Sentence (LOS) and Legal Meta-Sentence (LMS)
  • 3.2.1.4. Connection between LMS and LMS
  • 3.2.2. Legal Inference
  • 3.3. Fundamental Legal Meta-Rule Sentence (FLMRS)
  • 3.4. Legal Meta-Rule Sentence (BLMRS)
  • 4. Comparison of Yoshino’s LJ with Kelsen’s PTL
  • 5. Conclusions
  • 6. References