The legal theory proposals can be understood as a set of different solutions to legal and theoretical problems. While presenting the subject in this way may seem attractive, it is nevertheless not always transparent because it doesn’t precise what must be known to understand its problematic character. Hence, in this paper I analyze the concept of problem through the notion of relational predicate whereby I extract criteria to determine what should be considered a problem and by which standards its solutions should be evaluated. Afterwards, I employ the analysis results to discuss a well-known normative problem showing its analytical usefulness. The aim, indeed, is to contribute to a scarcely developed debate on the concept of problem.