Logical Jurisprudence

by Hajime Yoshino

2007 11 25 Lachmayer @ chello.at

Visualization of Legal Theory

Hajime Yoshino’s

Logical Jurisprudence

Visualisation by Friedrich Lachmayer

3rd July 2007

KEIO University, Tokyo

The Structureof Legal System

- in Terms of Logical Jurisprudence

2007/02/22IRIS 2007, Salzburg, Austria

by Hajime YoshinoMeiji Gakuin University

based on:

Logical Structureof Change of Legal Relation and

its Representation in Legal Knowledge Base System

June 4 – 8, 2007, Stanford, California11th International Conference on

Artificial Intelligence and Lawby Hajime Yoshino

Meiji Gakuin University

based on:

Metalevel

Scientific Audience

JurisprudenceState, Law

Stage of Rights and Duties

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

Law

DeductionDeduction

Natural Law Principles

Pufendorf

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

indiv. Judgements

International Law

Private Treaties

Customary Law

Legal Awareness

Traditional Legal Concepts

Constitution

Legal Hierarchy

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

Legal Philosophy

Traditional Juridical Concepts

Legal Dogmatics

Legal Sociology

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

Constitution

Basic Norm

Kelsen

Legal Hierarchy

indiv. Judgements

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

ScientificLogical Sentences

Logic

Yoshino

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

ScientificLogical Sentences

Logic

Kelsen Yoshino

1. Scientific Evolution

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

ComputerExpert Systems

Logic

Yoshino

ScientificLogical Sentences

2. newTechnical Perspectives

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

Introduction

ComputerExpert Systems

Logic

Yoshino

ScientificLogical Sentences

Applications

Applications

LogicalJurisprudence

LJ

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

wholeLegal System

LogicalJurisprudence

try to analyze and explain

ThreePrimitives

LJ

LJ try to analyze and explain

the whole legal system

using minimum elements

LJ

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

three Primitives:

S Sentence

V Validity

IR Inference RuleModus Ponens

(1) “sentence” LJ consider that norm as a meaning does not exist.

LJ starts from sentences.

(2) “validity” of sentencelegal validity as legal truth

“is_valid(sentence1, goal1,time1)”

(3) “inference rule”Modus Ponens: （（ A ⇒ Ｂ）＆Ａ） ⇒Ｂ

LJ starts form three primitives:

LJ

LegalSentences

LJ

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LN – Legal Norm LS – Legal Sentence

LJ starts not from Legal Norms

but from Legal Sentences.

Three Typesof

Legal Sentences

LJ

LRSLegal Rule Sentence

describesLegal Rules

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LR Legal Rule

LRSLegal Rule-Sentence

LFSLegal Fact Sentence

describesLegal Facts

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LF Legal Fact

LFSLegal Fact Sentence

LOSLegal Object Sentence

describes Legal Objects,especially Obligations

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LegalRole

LO Legal ObjectObligation

LegalRole

LOSLegal Object Sentence

LMSLegal Meta Sentence

describes about thevalidity of legal sentences

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LSLegal Sentence

validitydescribes

LMSLegal Meta Sentence

ELSElementary Legal Sentence

is the smallest unit of legal sentences.

“One must drive a car under 100 km /hour on a highway”

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

ELS

smallest unitof Legal Sentences

Structureof Connection of Legal Sentences

LS LS

LS

(1) “And” Structure of the Connection(2) Connection in Complex Sentence

(3) Connection of LOS with LMS(4) Connection of LMS with LMS

“And” structure

of the connection

of LS

Structure of Connection of LS: (1)LS LS

LS

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

a group of LSwhich has an unique name

LS LSAND

Connection

in

Complex Sentence

Structure of Connection of LS: (2)LS LS

LS

CLSComplex Legal Sentence

includes Legal Sentences

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

CLS

a group of LSwhich has an unique name

LS LSLS

Connection of LOS with LMS

Structure of Connection of LS: (3)LS LS

LS

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LSLegal Sentence

validity

LMSLegal Meta Sentence

Legal Inference

LJLS LS

LS

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LegalRules

LegalFacts

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LRS

LFS

LegalRules

LegalFacts

represented by

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

IR Inference RuleModus Ponens

LRS

proofedvalidity

LFS

LegalRules

LegalFacts

LOSrepresented by

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

Legal ObjectLegal State of Affair

IR Inference RuleModus Ponens

LRS

proofedvalidity

LFS

LegalRules

LegalFacts

LOSrepresented by

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

Legal ObjectLegal State of Affair

IR Inference RuleModus Ponens

LRS

proofedvalidity

LFS

LegalRules

LegalFacts

LOSrepresented by

ComputerExpert Systems

Logic

Time-Structure

of Legal Objects

LJ

The existence of obligation and the validity of legal object sentence

t0

t1

t2

t3

event1

T Obligation X exists “X is obligatory”

is valid

There is no obligationNo legal object sentence

Is valid

There is no obligation No Legal object sentence

is valid

Legal Object sentence Legal meta sentence

Obligation X turns up

Obligation X is expired

“X is obligatory”becomes valid

“X id obligatory”is terminated

X is obli-gatory

“X is ob-ligatory”is valid

event2

eventstime

Formalization of connection of LOS with LMS

• 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 a change of legal relation

t0

t1

t2

t3

event1

T Obligation X exists “X is obligatory”

is valid

There is no obligationNo legal object sentence

Is valid

There is no obligation No Legal object sentence

is valid

LOS s1 LMS s2, s3, s4

Obligation X turns up

Obligation X is expired

“X is obligatory”becomes valid

“X is obligatory”is terminated

X is obli-gatory

“X is ob-ligatory”is valid

event2

eventstime LMS s2, s3, s4

Legal State of Affairs are represented with legal object sentences whose validity are

proved.

• The legal meta sentences which describe the validity of object sentences are to be proved through legal reasoning.

• The whole legal object sentences, the validity of which are proved, represent the whole legal obligations.

• The legal reasoning to decide the validity of legal sentences is called legal meta inference, because it infer the validity “about” legal sentences.

• In legal meta inference, legal meta rule sentences are to be applied.

• What is legal meta rules sentences which decide the validity of legal sentences?

Formalization of decision that a LS is valid

t0

t1

t2

t3

event1

T

The legal sentence

is not valid

The Legal sentence

is not valid

LMS s2, s3, s4

“S” becomes valid

“S” is terminated

“S”is valid

event2

eventstime Fundamental LMS ‘0’

Connection

of

LMS with LMS

Structure of Connection of LS: (4)LS LS

LS

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

LMSLegal Meta Sentence

LRSLegal Rule Sentence

LMSLegal Meta Sentence

FLMRS

Fundamental Legal

Meta Rule Sentence

Fundamental legal meta rule sentence - FLMRS

This is a fundamental legal meta rule sentence implicitly taken for granted all regulations.

All other (positive) legal rule sentences regulate the

fulfillment of the first requirement (S becomes valid) or the second requirement (S is terminated)

of this rule.

A legal sentence S is valid for a goal G at the time T ←→ S becomes valid for G at time T1 before T & 　not(S is terminated for G after T1 and before T).

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

all Regulations

FLMRS FundamentalLegal Metarule Sentence

MRSLegal Metarule Sentence

LRSLegal Rule Sentence

BLRSBasic Legal Rule Sentence

Validity of the final highest legal meta sentence

Final founding the validity LS law through Basic Legal Rule Sentence

BLRS

The validity of the final, highest legal meta sentence, whose validity can not be deduce through the

application of legal meta rule sentences, is called the basic legal meta rule sentence (BLRS).

The validity of the basic legal meta rule sentenceis to be presupposed,

namely asserted as a fact sentence.

Metalevel

State, Law

Scientific Audience

LJ - Logical Jurisprudence

Stage of Rights and Duties

BLRSBasic Legal

Rule Sentence

MRSLegal Metarule Sentence

LRSLegal Rule Sentence

FLMRS FundamentalLegal Metarule Sentence

Comparison

of the results

of LJ with PL

State, Law

Computer-Application

LJ - Logical JurisprudencePL- Pure Theory

Kelsen Yoshino

„School“ Stage of Rights and Duties

Comparison of the results of LJ with PL

Kelsen Yoshino

Basic LRS

FundamentalLMRS

Basic Norm

similar solutions at the top of the system

State, Law

Computer-Application

LJ - Logical JurisprudencePL- Pure Theory

„School“ Stage of Rights and Duties

Kelsen Yoshino

LegalNorm

LegalSentence

LMS

Norm as a special Meaning

differentiationof juridicalsentences

LRS

LOS

LFS

Formal LogicTextuality

State, Law

Computer-Application

LJ - Logical JurisprudencePL- Pure Theory

„School“ Stage of Rights and Duties

Kelsen Yoshino

LJ ModellingLegal Cases

LO

LMS

LRS

LOS

LFS

Formal LogicTextuality

State, Law

Computer-Application

LJ - Logical JurisprudencePL- Pure Theory

„School“ Stage of Rights and Duties

Yoshino

LMS

LRS

LOS

LFS

Formal Logic

ComputerExpert Systems

LO

State, Law

Computer-Application

LJ - Logical Jurisprudence

Stage of Rights and Duties

Yoshino

Formal Logic

ComputerExpert Systems

LO

LMS

LRS

LOS

LFS

further supplement of LJ:

Legal Ontologies

State, Law

Computer-Application

LJ - Logical Jurisprudence

Stage of Rights and Duties

This lecture is dedicated to the memory of

This lecture is dedicated to the memory of

the famous Estonian Legal Philosopher

Thank youfor your

Attention!