Abstract
We propose a new formalization of legal competences, and in particular for the Hohfeldian categories of power and immunity, through a deontic reinterpretation of dynamic epistemic logic. We argue that this logic explicitly captures the norm-changing character of legal competences while providing a sophisticated reduction of the latter to static normative positions. The logic is completely axiomatizable, and we apply it to a concrete case in German contract law to illustrate that it can capture the distinction between legal ability and legal permissibility.
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Notes
What we call here static and dynamic rights have been labelled in various ways in the formal literature. Kanger called static rights the “type of the states of affairs” and dynamic ones the “type of influence” (Kanger 1972). Makinson instead used the “deontic family” and the “legally capacitative family” for static and dynamic rights, respectively (Makinson 1986). Bentham, von Wright and Hart on the other hand used “legal validity” and “norm-creating action” (Lindahl 1977), while (Lindahl 1977) called it “the range of action.”
The terminology used by Hohfeld might not fully reflect how terms like “power”, “immunity” or “liability” have been used in all the English-speaking literature. The work following (Kanger 1972) has, however, in important parts used that terminology. In other to situate our contribution better in that tradition, we use it here as well. We thank one of the anonymous reviewers of the JLLI for pointing us to the importance of making this caveat.
The results presented in this paper build on and extend the work reported in (Dong and Roy 2017). The present paper uses a more general condition for static conditional obligations, presents an improved version of the definitions of power and immunity, and a more in-depth conceptual discussion of the key points.
There have been a number of different proposals for defining “seeing to it that”. One popular family of approaches uses either one (Chellas 1980) or a pair of unary modalities (Kanger 1972; Lindahl 1977; Makinson 1986). All of them satisfy the T axiom as well as the E rule for substitution of logical equivalence. More recent approaches, as for instance the so-called “Chellas STIT”, use a normal, S5 modality (Chellas 1992; Horty 2000).
The complexity of the formula below is due to the fact that there might not be states that are maximal according to the relation \(\ge _{i \rightarrow j}\), i.e. states that have no other states strictly above them. When such states are guaranteed to exist, for instance finite models, this definition reduces to the more familiar definition in terms of truth in all maximal states.
Our definition of the update rule is slightly different from the standard one, used for instance Baltag and Smets (2008); van Benthem et al. (2014). Here two pairs (w, a) and \((w', a')\) are connected in the updated model as soon as \(a >^{{\mathcal {A}}_i}_{j \rightarrow k} a'\) or the other way around. This is so irrespective of whether w and \(w'\) were initially connected by \(\le _{j \rightarrow k}\). We made this modeling choice because it allowed us to capture more naturally some of the examples that we present here.
The semantics of conditional obligation that we use also yields, after the update, that at \((w_1, a_1)\) the city has an unconditional claim against Ivy to park and not display a permit. This counter-intuitive prediction is a consequence of the fact that this semantics validates \(O_{i \rightarrow c}(\varphi /\varphi )\), for any \(\varphi \). This means that, when the current state can only see itself according to the relation \(\le ^{{\mathcal {A}}_{John}}_{i \rightarrow c}\), we obtain that \(O_{i \rightarrow c}\varphi \) whenever \(\varphi \) is true. This is an issue that is shared by most preferential accounts of conditional obligation (Zvolenszky 2002), and that also affects some approaches based on default logic (Fuhrmann 2017). Addressing this thoroughly would require using a completely different approach to static conditional obligations, which would go beyond the scope of this paper. Note, however, that this is a defect that only affects the static conditional obligations. One could also interpret ”given \(\varphi \), \(\psi \)” dynamically, for instance using in terms of public announcements of the form \([\varphi !]\psi \), which are a special cases of the updates that we define here (Baltag and Smets 2008). It is well known that \([\varphi !]\varphi \) is not a valid formula (van Ditmarsch et al. 2007).
This view of legal powers as potential to change or ”flip”, so to speak, the truth value of certain legal facts is also used by van Eijck and Ju (2016). Note, however, that in that paper they restrict to the case where the agents have control over atomic propositions, while where the legal powers extend to any right \(T(j,k,\psi /\varphi )\).
These axioms are by and large standard, c.f. again (Baltag and Smets 2008; van Benthem et al. 2014). The only difference comes from our slightly non-standard clause in the lexicographic update rule, which results in the use of the universal modality in the first group of conjuncts in the second equivalence from below. See again footnote 6 on page 11 for details.
Our emphasis. Freely tranlated from “Nichteinhaltung von Beschränkungen aus dem der Vertretungsmacht zugrunde liegenden Rechtsverhältnis bei Vornahme eines Rechtsgeschäfts in Stellvertretung durch den Vertreter. Da die Vertretungsmacht von dem zugrunde liegenden Rechtsverhältnis abstrakt ist, führen solche Beschränkungen nicht zu einer Einschränkung der Vertretungsmacht, so dass sich auch eine unter Missbrauch der Vertretungsmacht abgegebene Erklärung grundsätzlich im Rahmen der Vertretungsmacht hält.” Source http://rechtslexikon.net/d/missbrauch-der-vertretungsmacht/missbrauch-der-vertretungsmacht.htm.
The German Civil Code of course explicitly voids this provision if there was proven collusion between buyer and seller, or when the seller should have known the terms of the agent’s contract.
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Acknowledgements
The authors would like to thank Alessandra Marra, Paul McNamara, Piotr Kulicki, and the anonymous reviewers for their valuable remarks and comments.
Funding
Huimin Dong is supported by the National Social Science Fund of China (No. 20CZX051, No. 17ZDA026) and the National Science Centre of Poland (No. UMO-2017/26/M/HS1/01092). Both authors are supported by the PIOTR research project (No. RO 4548/4-1).
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Dong, H., Roy, O. Dynamic Logic of Legal Competences. J of Log Lang and Inf 30, 701–724 (2021). https://doi.org/10.1007/s10849-021-09340-z
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DOI: https://doi.org/10.1007/s10849-021-09340-z