[el_dev_hell]

Usually by the Reasonable Person Test: https://en.wikipedia.org/wiki/Reasonable_person.

It can be pretty subjective, but it often gets clarified with enough common law precedent (which can be amended with a new law if it becomes abused/unfair/odd).

[NoboruWataya]

The top level comment is talking about Germany, which is not a common law jurisdiction.

[johannes1234321]

Precedent by other court decisions is still relevant for law interpretation in Germany. BVG and BGH decisions are law-like. With a somewhat good argument any court decision can become a good template for a case.

The opposite is also interesting to observe: In common law countries the written law also becomes more and more fine grained limiting jurisdical law making.