Logical Jurisprudence by Hajime Yoshino

1. Visualization of Legal Theory Logical Jurisprudence by Hajime Yoshino 2007 11 25 Lachmayer @ chello.at

2. KEIO University, Tokyo Hajime Yoshino’sLogical Jurisprudence Visualisation by Friedrich Lachmayer 3rd July 2007

3. based on: The Structureof Legal System- in Terms of Logical Jurisprudence 2007/02/22 IRIS 2007, Salzburg, Austria by Hajime Yoshino Meiji Gakuin University

4. based on: Logical Structureof Change of Legal Relation and its Representation in Legal Knowledge Base System June 4 – 8, 2007, Stanford, California 11th International Conference on Artificial Intelligence and Law by Hajime Yoshino Meiji Gakuin University

5. Metalevel State, Law Jurisprudence Stage of Rights and Duties Scientific Audience

6. Pufendorf Natural Law Principles Deduction Law

7. Traditional Legal Concepts Customary Law International Law Constitution Legal Hierarchy indiv. Judgements Private Treaties Legal Awareness

8. Traditional Juridical Concepts Legal Philosophy Legal Dogmatics Legal Sociology

9. Kelsen Basic Norm Constitution Legal Hierarchy indiv. Judgements

10. Logic Yoshino Scientific Logical Sentences

11. Logic Kelsen Yoshino 1. Scientific Evolution Scientific Logical Sentences

12. Logic Yoshino Scientific Logical Sentences 2. new Technical Perspectives Computer Expert Systems

13. Introduction Logic Yoshino Scientific Logical Sentences Applications Computer Expert Systems Applications

14. LJ Logical Jurisprudence

15. whole Legal System Logical Jurisprudence try to analyze and explain

16. LJ Three Primitives

17. LJ LJ try to analyze and explain the whole legal system using minimum elements

18. three Primitives: IR Inference Rule Modus Ponens V Validity S Sentence

19. LJ LJ starts form three primitives: • (1) “sentence” • LJ consider that norm as a meaning does not exist. • LJ starts from sentences. • (2) “validity” of sentence • legal validity as legal truth • “is_valid(sentence1, goal1,time1)” • (3) “inference rule” • Modus Ponens: （（A ⇒Ｂ）＆Ａ） ⇒Ｂ

20. LJ Legal Sentences

21. LS – Legal Sentence LN – Legal Norm LJ starts not from Legal Norms but from Legal Sentences.

22. LJ Three Types of Legal Sentences

23. LRS Legal Rule Sentence describes Legal Rules

24. LRS Legal Rule-Sentence LR Legal Rule

25. LFS Legal Fact Sentence describes Legal Facts

26. LFS Legal Fact Sentence LF Legal Fact

27. LOS Legal Object Sentence describes Legal Objects, especially Obligations

28. LOS Legal Object Sentence Legal Role LO Legal Object Obligation Legal Role

29. LMS Legal Meta Sentence describes about the validity of legal sentences

30. LMS Legal Meta Sentence describes validity LS Legal Sentence

31. ELS Elementary Legal Sentence • is the smallest unit of legal sentences. • “One must drive a car under 100 km /hour on a highway”

32. ELS smallest unit of Legal Sentences

33. LS LS LS Structure of Connection of Legal Sentences (1) “And” Structure of the Connection (2) Connection in Complex Sentence (3) Connection of LOS with LMS (4) Connection of LMS with LMS

34. Structure of Connection of LS: (1) LS LS LS “And” structure of the connection of LS

35. LS LS AND a group of LS which has an unique name

36. Structure of Connection of LS: (2) LS LS LS Connection in Complex Sentence

37. CLS Complex Legal Sentence includes Legal Sentences

38. CLS LS LS LS a group of LS which has an unique name

39. Structure of Connection of LS: (3) LS LS LS Connection of LOS with LMS

40. LMS Legal Meta Sentence validity LS Legal Sentence

41. LJ LS LS LS Legal Inference

42. Legal Rules Legal Facts

43. Legal Rules LRS represented by LFS Legal Facts

44. IR Inference Rule Modus Ponens proofed validity Legal Rules LRS LOS represented by LFS Legal Facts

45. IR Inference Rule Modus Ponens proofed validity Legal Rules LRS LOS represented by LFS Legal Facts Legal Object Legal State of Affair

46. Logic IR Inference Rule Modus Ponens proofed validity Legal Rules LRS LOS represented by LFS Legal Facts Computer Expert Systems Legal Object Legal State of Affair

47. LJ Time-Structure of Legal Objects

48. event1 T event2 Legal meta sentence time events Legal Object sentence The existence of obligation and the validity of legal object sentence No legal object sentence Is valid t0 There is no obligation “X is obligatory” becomes valid Obligation X turns up t1 X is obli- gatory “X is ob- ligatory” is valid “X is obligatory” is valid Obligation X exists “X id obligatory” is terminated Obligation X is expired t2 No Legal object sentence is valid t3 There is no obligation

49. For example: “‘It is obligatory for Anzai that Anzai deliver the goods to Bernard’ is valid at time 15.04.” is formalized as follow: S1: is_obligatory(‘Anzai’,deliver(‘Anzai’,’Bernard’,goods)). S2: is_valid(s1,t04_15). It is to be noted here that the object sentence is formalized as an entity which has it unique name. Anzai’s obligation to deliver the goods to Bernard turns up at time 04_09 ” means “It is obligatory for Anzai that Anzai deliver the goods to Bernard’ becomes valid,” which is formalized: S2: become_valid(s1,t04_09). Anzai’s obligation to deliver the goods to Bernard is expired at time 05_01 means “It is obligatory for Anzai that Anzai deliver the goods to Bernard’ is terminated at t05_01,” which is formalized: S2: is_terminated(s1,t05_01). Formalization of connection of LOS with LMS

50. event1 T event2 LMS s2, s3, s4 LMS s2, s3, s4 time events LOS s1 Formalization of a change of legal relation No legal object sentence Is valid t0 There is no obligation “X is obligatory” becomes valid Obligation X turns up t1 X is obli- gatory “X is ob- ligatory” is valid “X is obligatory” is valid Obligation X exists “X is obligatory” is terminated Obligation X is expired t2 No Legal object sentence is valid t3 There is no obligation