Modular Argumentation

Developing the idea of logic for interactions among distinct normative systems, Dung and Sartor (2011) propose a logical analysis of private international law based on modular argumentation. They take contract law cases as main examples.

Noting that conflict of laws is the legal technique deployed by legislators to co-ordinate different normative systems without imposing a hierarchy among them, they believe it uniquely provides lawyers and judges with tools to understand “the ways in which each system takes into account the existence, the content and im-plications of other systems” (id., p. 234). Besides, private international law

inter-actions are inter-systemic in kind for they occur between different legal systems, the coexistence of which is guaranteed by jurisdiction and choice of law mecha-nisms. Such mechanisms make certain that the case is allocated to a precise court and that the legal system according to which the case must be ruled is determined.

So, not only conflict of laws does not impose any overarching regulation, but also it does not establish priority relations between the systems involved in the cross-border case.

Starting from such premises, they assume the existence of different legal sys-tems L1, L2,…Ln, and model each Li as including:

 ChJur(Li): a set of choice of jurisdiction rules, establishing whether courts of Li

can hear and decide the case;

 ChComp(Li): a set of choice of competence rules, establishing which particular court of Li can decide it; and

 ChLaw(Li): a set of choice of law rules, identifying which substantive law, of Li

or of another legal system, the court has to apply.

For reason of simplicity, public policy, renvoi, and forum non conveniens, a common law principle according to which a court can discretionally neglect to hear the case in favour of another court, are explicitly not considered.

Based on Dung’s formal argumentation framework (1995), modular argumen-tation allows for representing legal knowledge in separate modules that can be re-ferred to, with apposite queries, whenever a specific issue requires it. Thus, the components of private international law, the different national laws that can be identified, as well as the doctrines can be adequately represented through distinct modules. Dung and Sartor’ modular logic focuses on the level of the definition of jurisdiction and competence of the domestic court, and on that of the identification of the applicable law, and prefers a credulous reasoning. The latter actually ena-bles the reasoner to consider all the outcomes that can be possibly derived from the available legal knowledge, in terms of doctrines and alternative conclusions, without prejudicially blocking any of them as it would happen in a sceptical ap-proach.

Let us briefly show how such modules practically work, and how they can be used to convey different doctrines for the interpretation of a provision. First con-sider the brusselsConventionMod, one of the five modules identified by Dung and Sartor (2011, p. 247). It defines jurisdiction in civil and commercial matters under the Brussels Regime established by the already mentioned Regulation (EC) no.

44/2001, Brussels I, in EU Member States. Two provisions are specifically con-sidered: article 2, according to which the defendant’s domicile in a contracting state determines the jurisdiction of the courts of that state; article 5, establishing two correctives to this connecting factor, the first in favour of the different place of performance of a contract, the latter in favour of the place, where the harmful event took place in matters relating to torts.

Module brusselsConventionMod hasJurisdiction(Country) ←

defendantHasDomicileIn(Country), contractingState(Country).

hasJurisdiction(Country) ←

contractDispute, placePerformance(Country).

hasJurisdiction(Country) ←

tortDispute, placeHarmfulEvent(Country).

The module operates, through a call, whenever the court of a contracting state S needs to verify whether it has jurisdiction for the case C:

call(brusselsConventionMod + Case(C), hasJurisdiction(S))

If the answer to the call is positive, the court of S has jurisdiction over the case C; otherwise, it rejects the case.

Let us now have a closer look at how the same method is then used for repre-senting alternative interpretations of one provision, specifically article 4 of the Rome convention (1980).⁷⁰ According to such provision, when the parties have not chosen the applicable law, the contract is governed by the law of the country with which it is most closely connected. Par. 2 presumes that “the contract is most closely connected with the country where the party who is to effect the perfor-mance which is characteristic of the contract has, at the time of conclusion of the contract, his habitual residence.” Par. 5 establishes that such presumptive connec-tion “shall be disregarded if it appears from the circumstances as a whole that the contract is more closely connected with another country.”

Dung and Sartor (2011, p. 254) identify a predicate for representing the hy-pothesis when the presumptive connection with the country of the performer’s res-idence is overridden:

overriddenConnViaPerformerTo(Country)

The doctrine (Hill 2004) presents at least two alternative interpretations of the par. 2 presumption, respectively the weak presumption theory and the strong pre-sumption theory. According to the former, the connection with the country of the performer’s residence is overridden whenever other factors (e.g., the place where the contract was stipulated) show a stronger connection with a different country.

This is the corresponding module:

Module weakPresViaPerformerMod overriddenConnViaPerformerTo(Country) ←

moreConnectedToContract(Country’, Country).

moreConnectedToContract(Country’, Country) degreeOfConnectionTo(Country’, X) degreeOfConnectionTo(Country’, Z) X > Z.

70 The 1980Convention on the Law Applicable to Contractual Obligations, or the Rome Con-vention, has been substantially replaced by Regulation (EC) no. 593/2008.

On the contrary, the strong presumption theory states that the connecting factor can be overridden only exceptionally, when it is completely insignificant in the particular case.

Module strongPresViaPerformerMod overriddenConnViaPerformerTo(Country) ←

insignificantConnectionViaPerformerTo(Country).

Finally, the two doctrines are inserted in the module corresponding to the Rome convention application, i.e., romeConventionMod: the application of the doctrines will solve the predicate overriddenConnViaPerformerTo(Country), depending on which one it is assumed and called.

Dung and Sartor have revealed the major role played by interpretation also in private international law as in any other rule application and form of legal reason-ing. The case of alternative interpretations of the same international or suprana-tional provision, a frequent occurrence in the application of EU regulations in the different Member States, shows that even the adoption of the same conflict of law rules does not completely avoid the possibility of applicative mismatches. Moreo-ver, even if the issue of different interpretations of the foreign provision within the domestic system is not explicitly taken into consideration in the analysis, it is ar-guable that modules can be implemented to express such different interpretations of substantive laws, national or foreign.