Editing Vagueness (section)

=== In law ===
Vagueness is also a problem which arises in law, and in some cases, judges have to arbitrate regarding whether a borderline case does, or does not, satisfy a given vague concept.  Examples include disability (how much loss of vision is required before one is legally blind?), human life (at what point from conception to birth is one a legal human being, protected for instance by laws against murder?), adulthood (most familiarly reflected in legal ages for driving, drinking, voting, consensual sex, etc.), race (how to classify someone of mixed racial heritage), etc.  Even such apparently unambiguous concepts such as biological sex can be subject to vagueness problems, not just from [[transsexual]]s' gender transitions but also from certain genetic conditions which can give an individual mixed male and female biological traits (see [[intersex]]).

{{anchor|Legal principle}}<!--- courtesy under WP:LINK, [[Albert Haddock]] links here]] -->
In the [[common law]] system, vagueness is a possible [[legal defence]] against by-laws and other regulations.  The legal principle is that delegated power cannot be used more broadly than the delegator intended. Therefore, a regulation may not be so vague as to regulate areas beyond what the law allows. Any such regulation would be "void for vagueness" and unenforceable.  This principle is sometimes used to strike down municipal by-laws that forbid "explicit" or "objectionable" contents from being sold in a certain city; courts often find such expressions to be too vague, giving municipal inspectors discretion beyond what the law allows. In the US this is known as the [[vagueness doctrine]] and in Europe as the [[principle of legal certainty]].