Lezione sulla Strategic argumentation in the law

What players can do, strategies:

GAME = Interaction between 2 or more individuals called players, specifying all strategies available to them and any order of execution of the action that each player can perform.

STRATEGY = Every strategy for a player. A in a game is a comprehensive plan of action that A can accomplish in a possible situation of the game and that determines a result, + or – for A and the other players involved.

STRATEGY PROFILE = Combination of strategies for each player. 2 parties:

• A -> S strategy -> I take 5, you get 6. (in a scale from 0 to 5)
• B -> T strategy -> Uses a scale from 0 to 10)

(S * T) = Possible strategy profile of the A B game.

THE NATURE OF PLAYERS = They are rational and selfish, able to assign a value to each of the results that may be expected from joint decisions of all players, make decisions that are the best strategies to maximize their individual utility.

SIMULTANEOUS OR SEQUENTIAL = Games are simultaneous if the players make

Decisions are made at exactly the same time or, if they don't, each player decides without knowing the choices of the other player (which is equivalent to the case where the choices are made simultaneously).

Complete or incomplete knowledge of the players: If the parties have complete knowledge of the game, this means they don't know the rules and structure of the game, number of players, rational nature, and their possible strategies. Utilities can be obtained for each of the joint decisions.

Number of players: Greater or equal to 2.

Measure of utility: The utility assigned to the results or to the strategies of the agents are measurable with cardinal numbers (integers).

Interpersonal comparison of utility: It's possible to compare the utility evaluation each player assigns to a certain result in a game. "We need the same scale to measure utility: PAIN AND PLEASURE." There is a large gap in this perception. It is an approximation. Compare the preferences.

Nash equilibrium -> Nobel Prize in economics.

A strategy profile where every player plays a best response against the other players simultaneously. A combination of strategies.

PRISONER'S DILEMMA

Playing war is rational and selfish. Temptation is too strong -> WAR | WAR. There is no reason to be cooperative, but this is the ruin of humanity.

Dung 1995 - The theory of ABSTRACT ARGUMENTATION FRAMEWORKS

2 arguments -> 2 Strategies War and Peace

Valuate the arguments

Given an argumentation framework determine the justification state.

Justified and undefeated

Overruled or defeated (by justified argument)

Defensible or provisionally defeated - Neither justified nor overruled - They jointly survive.

In a network of argumentation a single argumentation can be:

1. IN (the most "skeptical" argumentation semantics) - All the other arguments that defeat it are out
2. OUT - Some argument that defeat it is out
3. UNDECIDED - We don't know which is stronger

Chain

Manual

attack

Floating arguments

Testimony A

Testimony B

They defied each others, they are not reliable, so we don’t know. This is discussing.

The criminal procedure is different in the European continental and in U.S.

ASSUMPTION:

- The argumentation game terminated of a player withdraws

- Each argumentation game induces a reply tree, which consists of the argument moves as nodes and their target relations as links.

Each move is what to do in order to attack the other part.

The result of the argumentation three are the utilities (money for example) for the parties. Equilibrium can be this.

One of the 2 players plays the 0 strategy (the lost is a rational, good choice for this sometimes is better to lose part, LEGAL DISPUTES because in MOVES ARE A COST. For example expert testimonies have to be paid.

The utility of the winning could be less than the cost of the dispute.

To minimize cost and to maximize the utility. Equilibrium in legal disputes can corresponds to lose it.

We have incomplete information, the DEF miss to

know something.

In legal disputes, it is crucial that the parties don't know the same things, they have different information.

YOU

Asymmetries of information

IF → DISCLOSE YOUR PRIVATE