Presentation on theme: "General Norm Change Emil Weydert and Richard Booth Individual and Collective Reasoning Group University of Luxembourg."— Presentation transcript:
General Norm Change Emil Weydert and Richard Booth Individual and Collective Reasoning Group University of Luxembourg
Outline of talk The problem of Norm Revision Basic concepts Normative states Basic revision requirements A first method
The Problem normative state + new norms = ?? – What is a normative state? – How to revise it? – Revision first, contraction later
The Basic Concepts L is some language closed under usual prop. connectives. A norm is a conditional with L – “if holds then should hold” A set of norms can be coherent or incoherent Any set of norms induces (conditional) obligations
Normative States: Ingredients Different types of priority between norms: – Temporal (order of introduction) – Commitment (active/inactive) – Explicit (authority) – Implicit (specificity-like) We consider only first 2 for now
Normative States A normative state N is of the form – is a prior set of norms – is the sequence of revision inputs received thus far – is the set of currently active norms – Obligation is induced by N iff it’s induced by
Minimal Requirements on X is coherent if – Not necessarily for all i – If N = then not necessarily
The Revision Problem Given: – normative state N and coherent norm-set Want: – new normative state N N = for some new set of active norms Question: What is ?
Basic Postulates for X’ By definition of normative state, we must have: – is coherent – (Success) Might also expect: – If is coherent then (Conservativeness) More?...
A First Method: Some Notation Given normative state N = let for i = 0,…,n Given 2 norm-sets, set is the family of norm-sets s.t. 1) is coherent 2)If then is incoherent
A First Method Construct iteratively Start with Then for i = n,….,0 – If then – else
A First Method: Simple Examples Examples use a specific definition of “coherence”: – is coherent iff there is no s.t. and can be derived from in System P
Example 1 N =, where: Suppose Then
Example 2 N =, where: Suppose Then
Conclusion Preliminary framework for Norm Revision Incorporates temporal and “commitment” (active/inactive) priorities Give first method based on maximal coherent sets, giving active norms “privilege” Ongoing work….
Norm Change Workshop participants are warmly invited to: JANUARY 29……SUBMISSION DEADLINE JANUARY 29…….SUBMISSION DEADLINE JANUA