> Under Suber's initial ruleset, rules are divided into two types: mutable and immutable. The main difference between these is that immutable rules must be changed into mutable rules (called transmuting) before they can be modified or removed. Immutable rules also take precedence over mutable ones. A rule change may be:

the addition of a new mutable rule
an amendment to a mutable rule
the repeal of a mutable rule
the transmutation of a rule from mutable to immutable
or the transmutation of a rule from immutable to mutable