the GNU version of the Collaborative International Dictionary of English
n. The quality of being unalterable or unchangeable; permanence.
The Century Dictionary and Cyclopedia
n. Unalterability.
Word Usage
"Arguably, he could have done a lot more; he could have let Calvin turn seven, which would have opened up a new world of possibilities, but it would also have denied the inalterability that some see as intrinsic to the comic strip art form."