Introduction
This post deals with the rules of transition between general practical discourse and other types of discourse. In the general practical discourse, value judgments and norms that oblige, allow or prohibit certain actions to be practiced are discussed. The other types of discourse are necessary when questions arise about facts, language problems, and discourse theory. These rules apply equally to legal discourse because it is a special case of general practical discourse.
Analysis
Alexy (1989, p. 206) formulates the transition rules as follows:
(6.1) It is possible for any speaker at any time to make a transition into a theoretical (empirical) discourse.
(6.2) It is possible for any speaker at any time to make a transition into a linguistic-analytical discourse.
(6.3) It is possible for any speaker at any time to make a transition into a discourse-theoretical discourse.
Rule (6.1) applies to the discussion of facts, among which are those referring to the conditions of application and the consequences of norms and value judgments. Alexy (1989, p. 206) states that rules of reasonable presumption should be used when empirical knowledge cannot be obtained with certainty. Despite indicating the need for these rules of presumption, he does not develop them.
Rule (6.2) makes it possible to discuss communication problems between the participants of the discourse. The problems are related to ambiguity, vagueness, contradictions and omissions in the use of language.
The argumentative rules of discourse theory cannot always be complied with for three main reasons (Alexy, 1989, p. 206): 1) the interpretation of these rules depends on the preconceptions of the speakers; 2) such rules do not detail all the steps that must be performed in practical discourses to achieve a correct result; 3) some argumentative rules can only be complied with in an approximate way. To deal with these limitations, rule (6.3) allows the speakers to debate the argumentative rules.
Conclusion
The three transition rules allow the speaker to move from general practical discourse to types of discourse that discuss other categories of topics, such as facts, language, and discourse theory itself. Although Alexy stresses the need for rules of reasonable presumption to deal with situations of incomplete knowledge about facts, he does not develop these rules of presumption.
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.
Below are links to the posts in which I examined the previous groups of argumentative rules:
1) First group;
2) Second group;
3) Third group;
4) Fourth group;
5) Fifth group.