Validación de la Hipótesis

Interpretive canons are those rules that have to be applied for interpreting statutes.

Usually, legal systems not only provide for lists, more or less complete, of such canons of construction,³² but also establish priorities among them.³³ Besides, Su-perior Courts are often charged with deciding on the interpretation of controversial

32 For instance, articles 1362–1371, Italian Civil Code list the interpretive criteria to be applied for interpreting contracts: such list represent a guideline not only for the parties, but also for the judge on the occasion of dispute resolution.

33 As mentioned in chapter 1, in Italy, article 12 of the preliminary dispositions to the Civil Code establishes a hierarchy between canons of interpretation.

pieces of legislation, and with fostering an as uniform as possible interpretation of the law,³⁴ which is one of the pillars of legal certainty.

To appreciate how interpretive canons function, consider the argument form ordinary meaning, as presented by MacCormick and Summers (1991, p. 513): a statutory provision can be interpreted according to the meaning an ordinary speak-er of the language would ascribe to it as its obvious meaning, unless thspeak-ere is ade-quate reason for a different interpretation. Interpretive arguments seem to show recurring structural elements (Sartor et al. 2014):

 There is an expression E, the meaning of which is doubtful;

 This expression occurs in a document D (e.g., a statute, or a contract);

 E has a setting S that is relevant for interpreting it (e.g., ordinary language, technical meaning, precedent);

 E in D would fit this setting S by having interpretation I;

 E ought to be interpreted as I if all the previous elements are satisfied.

Sartor et al. (2014) recognise the following pattern of interpretive argument:

If expression E occurs in document D, E has a setting of S and E would fit this setting of S by having interpretation I, then, E ought to be interpreted as I.

Each interpretive argument is a pattern of reasoning in the form of ‘if-then’

rule, licensing a deontic interpretive claim (‘ought/ought not’). In so doing, it aims at supporting certain interpretations, and relates to other interpretive arguments ei-ther supporting their interpretive conclusion (aggregation of arguments), or attack-ing it. In an abstract argumentation framework such as ASPIC+ (Prakken 2010), canons of interpretation are seen as defeasible rules, so that their conclusion, i.e., E ought to be interpreted as I, can be abandoned in presence of better-supported interpretations. The AF includes both strict and defeasible rules expressed in an underlying logical language L, and preferences between those rules are expressed by formulas like r1 > r2, establishing which interpretive argument prevails in the attack. Attacks occur in the standard three ways: by producing a counterargument, i.e., rebutting it; by denying that the interpretive argument holds in the present case, i.e., undercutting it; by claiming that one of the antecedents of the argument does not hold, i.e., undermining it.

Rotolo et al. (2015) have refined such argument-based model of legal interpre-tation, by presenting a logical machinery, based on deontic defeasible logic, for modelling interpretive arguments. They build on the next basic intuitions:

 Interpretive canons are represented as defeasible rules: their antecedent condi-tions can be of any type (assercondi-tions, obligacondi-tions, etc.), and their conclusion is an interpretive act that leads to interpret a provision n in a certain way as a result.

 Interpretation is both the activity that ascribes the meaning to a provision n (A-interpretation), and its outcome, corresponding to the meaning obtained by ap-plying that interpretive canon (O-interpretation).

34 For Italy, see footnote no 7.

 It can be established a standard priority relation over interpretation rules, so that it is possible to handle and solve conflicts occurring among interpretive canons (e.g., Rule 1 > Rule 2); it is worth noting that a ranking between pretive rules can be useful also in absence of a proper conflict, so that the inter-preter is aware of what canons should be preferably applied in general (for in-stance, if both the ordinary meaning canon and the systemic canon give the same interpretive result, the first should be normally used to justify the inter-pretation).

 Both A- and O-interpretation can be admissible, if it can be proved by a defea-sible interpretive rule, or obligatory, if it is the only admisdefea-sible interpretation of n; note that this intuition develops the claim that an expression E in a document D (e.g., a statute) ought, ought not, may or may not be interpreted in a specific way (Sartor et al. 2014).

 A provision n can be abstract, if its logical structure is not analysed, or struc-tured, if it corresponds to a linguistic sentence having the structure of a rule a1,…, an⇒ b; along with this distinction, the authors propose two options for modelling interpretive arguments.

Following the same line of research, Walton et al. (2016) have further consid-ered some contested cases of statutory interpretation. Not only have they proposed the distinction among positive and negative interpretive arguments, but have also identified some critical questions:

CQ1: What alternative interpretations of E in D should be considered?

CQ2: What reasons are there for rejecting alternative explanations?

CQ3: What reasons are there for accepting alternative explanations as better than (or equally good as) the one selected?

Arguing with different interpretations has also been viewed through the lenses of practical reasoning: interpretations promote certain applications of the law that are seen as actions with possibly good or bad consequences. Thus, a value-based approach (Bench-Capon 2003), already used to address the issue of interpreting statutes with purposes, can turn out useful (Atkinson and Bench-Capon 2007, At-kinson et al. 2005): Dung’s abstract AF is extended by providing each argument with a value that it promotes and by ordering all the values. The system resolves the attack relation among the conflicting arguments by comparing the value pref-erence they support. An argument scheme for practical reasoning that can reason-ably be applied to legal interpretation is also identified:

In the current circumstances R Action A should be performed To bring about new circumstances S Which will release goal G

And promote value V

Critical questions challenge the truth of the circumstances, explore the credibil-ity of the imagined consequences, look for alternative ways to promote the same

value, investigate potential disadvantages linked to the action (e.g., demotion of other important values), and, finally, put to the test the legitimacy of the value.

Also factor-based reasoning, as developed in CATO (Aleven 1997), has been combined with an argument-based approach (Prakken et al. 2015). The ASPIC+

framework is the formal setting for the comparison between two famous cases of US trade secret law, Mason v. Jack Daniels Distillery³⁵ and M. Bryce & Associ-ates, Inc. v. Gladstone.³⁶ The comparison is accomplished through the identifica-tion and use of factors (expressed, e.g., in the following form: F6 Security-measure (p), where p stands for ‘pro-plaintiff factor’) drawn from the cases. Ar-guments are then constructed with those factors, and comparisons are modelled in terms of similarity or distinguishing. As a result, a directed graph in Dung-style AF is obtained.