Introduction
This post covers the argumentative rules that regulate the forms of interpretative arguments according to Robert Alexy.
Concept of argument forms in general
Argument forms are structures of propositions used by a single speaker. They are composed of one or more premisses, a conclusion, and a rule that authorizes the passage from premisses to conclusion (Alexy, 1989, p. 92). Forms of argument are not to be confused with rules because they do not oblige, forbid or allow something to be done.
Concept of forms of interpretative arguments
Forms of interpretative arguments are used by a speaker to support or attack the interpretation of a norm. With the exception of forms of semantic arguments, forms of interpretative arguments can be used in situations other than the interpretation of norms, such as, for example (Alexy, 1989, p. 244):
a) conflict of norms;
b) limitation of the scope of application of the law;
c) justification of norms not obtained from the text of the law.
Argumentative rules with regard to the interpretation of legal norms
Alexy (1989, p. 246-250) formulates four rules that regulate the forms of interpretative arguments of legal norms, reproduced below:
(J.6) Saturation – that is a full statement of reasons – is required in every argument which belongs among the canons of interpretation.
[…]
(J.7) Arguments which give expression to a link with the actual words of the law, or the will of the historical legislator, take precedence over other arguments, unless rational grounds can be cited for granting precedence to the other arguments.
[…]
(J.8) Determinations of the relative weight of arguments different in form must conform to weighting rules.
[…]
(J.9) Every possibly proposable argument of such a form that it can be counted as one of the canons of interpretation must be given due consideration.
All the premisses of a form of argument must, according to rule (J.6), be provided by the speaker. Thus, for example, it is not enough to claim that an interpretation should be accepted because that would be the will of the historical legislator without presenting the empirical premisses that prove what that will would be.
Rule (J.7) establishes a prima facie hierarchy between, on the one hand, semantic arguments and those based on the will of the historical legislator, and, on the other hand, the other kinds of legal interpretative arguments. This hierarchy can be disregarded if the speaker presents reasons for other types of arguments to prevail.
According to rule (J.8), when several types of legal interpretative arguments are used, the speaker must choose between them based on weights assigned to them according to weighting rules. Such rules of weighting aim to avoid arbitrariness in this choice.
Finally, rule (J.9) imposes a duty of completeness. To achieve it, the interpreter must consider all the arguments that can be formulated with the canons. Therefore, if possible, he or she must formulate semantic, genetic, historical, comparative, systematic, and teleological arguments for the interpretation he or she holds.
Conclusion
In summary, the rules for the use of forms of interpretative arguments establish: 1) the requirement of saturation of premisses; 2) the prima facie hierarchy of forms of semantic arguments and forms of arguments referring to the will of the historical legislator; 3) the weighting between forms of arguments; 4) and the completeness in the use of all arguments that can be formulated with the canons of interpretation.
Bibliographic references
ALEXY, Robert. A Theory of Legal Argumentation: The Theory of Rational Discourse as Theory of Legal Justification. Translated by Ruth Adler and Neil MacCormick. 1st ed. New York: Oxford University Press, 1989.