A basic distinction in legal scholarship lies between descriptive claims (what is the law?) and normative claims (what should be the law?). In this post I argue that one can easily fall into the trap of making one instead of another, due to: 1) law’s normative character; 2) law’s hierarchical (or heterarchical) structure; and 3) often argumentative style of legal reasoning.

Initial claims:
1. Since law itself is normative, a descriptive claim about law will be a normative claim about sth else;
2. A descriptive claim about a higher order provision (in Kelsen’s sense or some heterarchical sense, e.g. about the EU law) will be a normative claim about a lower order provision;
3. When law is ambiguous, a seemingly descriptive, ‘interpretative’ claim might actually include extra-legal normative components.

Examples:
Assume a hypothetical state, the Republic of Silesia, where the Traffic Regulation Act sets the default speed limit at 60 km/h in the towns.

Descriptive question: what is the default speed limit in the towns in  the Republic of Silesia? is pretty straightforward, and the answer: ‘the speed limit is 60 km/h’ is a correct, descriptive claim.
But this claim already includes a normative statement: ‘people should not drive faster than 60 km/h in Silesia’.

However, a normative question: what should be the default speed limit in towns in Silesia? invites different possible types of answers:
#1: The speed limit should be lower, because I’m afraid of cars driving so fast;
#2: The speed limit should be higher, so that people can be more efficient, move faster and so have more time to work, due to saving time on transportation;
#3: The speed limit should be higher, because the art. X of the Constitution of the Republic of Silesia states ‘The Republic ensures the citizens’ right to move around quickly’.

Higher/lower limit is insignificant here, what matters is the reasons behind the normative claims.
In #1, this is just an opinion;
in #2 a higher-level normative claim: ‘law should maximise the efficiency’ is assumed, though this claim is external to the legal system;
in #3 a descriptive claim about higher level law (constitution) is made, together with a normative claim: ‘lower level norms should comply with higher level norms’, which is internal to the legal system, and could be summarised as an internal normative claim: ‘law should make sure that citizens can move around quickly’.

Note that #2’s normativity comes from outside of the legal system, while #3’s from the inside.
Why does it matter?
Because one could claim that a statement: ‘The speed limit in towns in Silesia must be higher, because the current one is unconstitutional’ is actually a descriptive claim about the law.
In other words: seemingly normative statements about the law (due to the lingual side and usage of the modal verbs like ‘should’, ‘ought to’ or ‘must’)  can be considered descriptive statements by some scholars.

One should bare in mind that when making any claim about the law, one sees at least 3 levels:
1. Reality;
2. Legal provisions in statutes;
3. Constitutional/human rights provisions.

When making a descriptive claim about a higher level, one makes a normative claim about the lower level; when saying what the law is, one says how the reality should be; when saying what the constitutional norms are, one says how the lower level law should be. All these normative statements are internal to legal system.

However, there is a space for ‘cheating’ here. For example, it is not obvious that the speeding limit must be higher, maybe it is sufficient. This is already an argumentative exercise.

 

Now, the picture gets more complicated when one makes a normative claim based on reasons external to the legal system. These claims, again, can be directed at different levels:
1. People should be moving around quickly to be efficient;
2. Law should protect safety of the citizens, because human life is the highest value.
3. The silly provision about the right to move around quickly should be taken out of the Constitution, because it only causes confusion.

The importance of the distinction is high, because one can argue that executing a normative proposition internal to the law is a legal action, while executing one external to the law is just political action.

Now, this gets even more complicated when legal provisions are not straightforward.
Assume the Constitution states: ‘The Parliament of Silesia elects the Justices of the Constitutional Court and President of the Republic accepts the vow from them’ and assume that the Parliament has elected 4 justices, but the President refused to accept the vow.
The question begging a descriptive answer: ‘Is the President allowed not to accept a vow from the justices?’ needs an argumentative argument actually; and the reasons invoked might be internal, but might just as well be external to the legal system.
One can imagine both an affirmative and a negative answer, about which it is hard to state whether they describe the law, or just state as it should be.

In consequence, a rigid scholar should be always be explicit about the internality or externality of the source of normative claims he or she is making; and about the level about which a claim is made. Otherwise, falsity of the theories might hide to deep in the argument to be detected.