Cats presumably have a reputation for having nine lives because they are observed in situations where they appear to narrowly escape dying, by a hair's-breadth chance.

I was comparing this to quantum immortality, while making an indirect reference to Schrodinger's cat as well... implying that Schrodinger's cat always turns up alive, due to cats' quantum immortality-based nine-lives capability. ;-)

(Cat-thropic principle, perhaps?)