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How to justify a backing’s eligibility for a warrant: the justification of a legal interpretation in a hard case

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Abstract

The Toulmin model has been proved useful in law and argumentation theory. This model describes the basic process in justifying a claim, which comprises six elements, i.e., claim (C), data (D), warrant (W), backing (B), qualifier (Q), and rebuttal (R). Specifically, in justifying a claim, one must put forward ‘data’ and a ‘warrant’, whereas the latter is authorized by ‘backing’. The force of the ‘claim’ being justified is represented by the ‘qualifier’, and the condition under which the claim cannot be justified is represented as the ‘rebuttal’. To further improve the model, (Goodnight, Informal Logic 15:41–52, 1993) points out that the selection of a backing needs justification, which he calls legitimation justification. However, how such justification is constituted has not yet been clarified. To identify legitimation justification, we separate it into two parts. One justifies a backing’s eligibility (legitimation justification1; LJ1); the other justifies its superiority over other eligible backings (legitimation justification2; LJ2). In this paper, we focus on LJ1 and apply it to the legal justification (of judgements) in hard cases for illustration purposes. We submit that LJ1 refers to the justification of the legal interpretation of a norm by its backing, which can be further separated into several orderable subjustifications. Taking the subjustification of a norm’s existence as an example, we show how it would be influenced by different positions in the philosophy of law. Taking the position of the theory of natural law, such subjustification is presented and evaluated. This paper aims not only to inform ongoing theoretical efforts to apply the Toulmin model in the legal field, but it also seeks to clarify the process in the justification of legal judgments in hard cases. It also offers background information for the possible construction of related AI systems. In our future work, LJ2 and other subjustifications of LJ1 will be discussed.

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Notes

  1. Goodnight further maintains that “[w]hen [the selection of backing was] brought into question, such an inference becomes a claim defended by showing sound reasons for the selection of backing pertinent to a shared context” (Goodnight 1993, p. 41). This indicates that the legitimation inference also has a justificatory function. In this essay, we emphasize the justificatory function and subsequently refer to it as “legitimation justification”.

  2. Compared with an easy case, “[t]he decision [of a hard case] does not [simply] follow from a legal rule and a description of the facts (cf. Dworkin 1977, p. 81) [, but] from an expanded set of premises containing, inter alia, a value statement, a rule or another statement the decision-maker assumes but cannot easily prove” (Peczenik 2009, p. 15; italics added).

  3. For a discussion of hard cases caused by fact-related issues, see Xiong and Zenker (2018).

  4. The AI and law studies could only roughly be divided into two approaches, i.e., case-based studies (e.g., McCarty and Sridharan, 1981; Rissland and Ashley 1987; Berman and Hafner 1993) and argument-based studies (e.g., Prakken 1993; Gordon 1995; Prakken and Sartor, 1996b; Verheij 1996; Hage 1996; 1997; Prakken and Sartor 1998), since the distinction is relative (Skalak and Rissland 1992) and both types are somehow interchangeable (Prakken and Sartor 1998).

  5. Another implicit requirement is the institutional requirement, which asks, for instance, if the procedure follows the subject’s rights and the legal process.

  6. Kelsen (1949, p. 30) asserts that “[t]o say that a rule is valid is to say that we assume its existence […].”.

  7. Nevertheless, there are two main approaches of positivism: one is “restrictive” construal, e.g., “hold[ing] that it can never be a criterion of legal validity that a rule possess moral value” (Patterson 2010, p. 230; also see Raz 1979, pp. 37–52; 1985, pp. 311–20), and the other is “inclusive” construal (“incorporationism” or “inclusive legal positivism”), which “only commit[s] to two weaker claims […]” (Patterson 2010, p. 230; also see Hart 1994). Discussions can be even more complicated, but given that all legal positivists consider social conventions the fundamental factor in deciding that a rule is legal, we present Fig. 9.

  8. Like Shapiro (2011), we consider the “legal system” to include all components of it, e.g., all the legal rules.

  9. Strictly speaking, a fact cannot provide a description, which instead should be provided by the statement of the fact.

  10. As Mulligan and Correia (2017) hold, “Facts […] are opposed to theories and to values (cf. Rundle 1993).”.

  11. Some relevant studies have been conducted by AI and law researchers. For instance, Bench-Capon and Modgil (2017) make use of an argument scheme based on values to show how value-based reasoning can be used to determine the violation of a norm. As another instance, Berman and Hafner (1993) identify the teleological components of legal judgments and acknowledge that they can be used in a HYPO-like framework for case-based legal arguments. For such research, Bench-Capon (2002) recapitulates and combines it with a HYPO system. For another search on value judgment formalism and its experimental implementation in the VJAP system, see Matthias Grabmair (2017).

  12. On this point, we diverge from Perelman and Olbrechts-Tyteca (1958), who contend that the argument scheme establishing the structure of reality is parallel to the argument scheme based on the structure of reality.

  13. We thank the anonymous reviewer who pointed out this distinction.

  14. As Prakken suggests, there can be a third party in the persuasion dialogue who holds a neutral attitude towards the topic proposition p (Prakken, 2006, p. 167).

  15. As CQ-2.1 is not asked in a way that can be answered by ‘yes’ or ‘no’, we concede that there can be many formulations of answer that would attack the original argument, and ‘there is no intended category of the legal norm N’ is only one of them.

  16. For a detailed discussion on the burden of criticisms, see Krabbe and van Laar (2011), van Laar and Krabbe (2013), and Walton (2014).

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Acknowledgements

We are grateful to the two anonymous reviewers for this journal for their extremely insightful and constructive comments and suggestions. For useful comments on an earlier draft, we also thank audience members at the 3rd European Conference on Argumentation, 24-27 June 2019, Groningen, The Netherlands. Shiyang Yu acknowledges the support from the National Social Science Foundation of China (No. 19ZDA042).

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  1. College of Philosophy, Nankai University, Tianjin, China

    Shiyang Yu

  2. Law School, Shenzhen University, Shenzhen, China

    Xi Chen

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Yu, S., Chen, X. How to justify a backing’s eligibility for a warrant: the justification of a legal interpretation in a hard case. Artif Intell Law 31, 239–268 (2023). https://doi.org/10.1007/s10506-022-09311-0

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