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!