Introduction
This post aims to analyze the limits of general practical discourse and why they make legal discourse necessary.
Analysis
The limits of general practical discourse stem from three main causes (Alexy, 1989, p. 206): 1) participants’ preconceptions in discourse influence how they interpret argumentative rules; 2) such rules do not detail all the steps of the procedure performed to achieve a correct result; 3) some argumentative rules can only be complied with in an approximate way.
As a result of these limits, it is possible that a result of a general practical discourse and the opposite of this result conform to argumentative rules. For example, if this opposition occurs in an interaction between two persons who want to determine which norm they should comply with, they will be in a situation of conflict that cannot be resolved by the general practical discourse. Thus, legal rules are needed to define which of the results should prevail (Alexy, 1989, p. 207-208).
Conclusion
Since obedience to the argumentative rules of general practical discourse does not always lead to a single correct result, legal rules are needed to define which result should predominate.
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.