considered to be binding, but are nevertheless treated as law. Because precedents are in fact
treated as law, they are a source of law in the sense that they are a form in which law
originates. But there is no legal duty to treat them as law. Therefore precedents in the civil
law tradition are merely a source of origin of the law, but not a validity source.
Nowadays, most legal rules are valid legal rules for the reason that they werelaid
downwith the intention that they would become part of the law. In other words,
currently most laws arepositive law. This seems so obvious that it requires some
explanation as to why it is actually not obvious.
2.2.1 Social Rules
There are two ways in which a rule can exist within a social group, namely as a
social rule and as what may be called an “institutional rule.” A social rule exists
within a group if the members of this group tend to follow this rule, if they see
violations of this rule as a reason for (self-)criticism, and if they believe that the
other members of the group do the same.
An example would be a club of film lovers. They have the rule (but not a legal rule) that a
member of the club has to go to the cinema at least once a week and should write a review of
the film for the website of the club. The existence of the rule manifests itself mainly in that
most members do in fact go to the cinema every week and write about it. Moreover, if a
member of the club does not go to see a film in a particular week, she tends to reproach
herself for that, and the other members of the group may criticize her for this reason.
Moreover, she expects that other club members also feel somewhat guilty if they did not go
to the movies and also expect criticism for that reason.
This situation should be distinguished from a group of teenagers who only have the
custom to visit the cinema every week and to blog about it afterwards. If they do not go to
the cinema in a particular week, neither do they feel remorse, nor do they see not going as a
reason for criticism. These teenagers have a custom or habit, but no rule.
Social rules can only exist if they are, by and large, effective. This effectiveness
requires that the members of the group in which the rule exists tend to comply with
the rule, as well as that they consider violations of the rule as a reason for criticism.
2.2.2 Institutional Rules
Institutional rules exist if their existence follows from the application of some other
rule. This other rule may, for instance, hold that all the rules created by Parliament
are valid rules.
Such a rule exists in (almost) all legal systems, but merely as a rule of customary law. It is
not formulated explicitly.2 Sources of Law 25