Consciousness is often said to disappear in deep, dreamless sleep. We argue that this assumption is oversimplified. Unless dreamless sleep is defined as unconscious from the outset there are good empirical and theoretical reasons for saying that a range of different types of sleep experience, some of which are distinct from dreaming, can occur in all stages of sleep.
If the threshold changed, the actual definition changed. The same words to describe a different point. If the definition described two different things, its changed. That's basic and simple reasoning. If a definition no longer describes the same thing, it's because it's actual meaning has changed.
yes, the definition changes. it used to mean one point. now it means a point 10 miles away. come on. simple substitution. if you define it only with relative terms then its poorly defined as there's no actual concrete meaning. so you either have a poorly defined term or you have a term that has changed meaning over time. which still makes it poorly defined. i don't know how else to explain it. so i'm going to leave it here. this is going in circles.
I think I know what you mean, but plenty of terms have relative definitions ("behind", "bright", "x+1", "etc"... etc). If you're looking for an absolute point, you won't find one, because their meaning is the relationship itself.
Both "life" and "death" define a state relative to another. The definition of "life" is a particularly tricky one, because it includes multiple relative definitions like "growth", "reaction", "functioning", and a "reproduction" that includes both cloning and "imperfect" cloning. Being "death" the opposite, it's necessarily as relative and tricky too.
What surprises me, is you wouldn't accept the relative/changing definition as a valid definition itself.
Guess that could be an interesting conversation, potentially shedding some light on different worldviews... but I don't really know where to begin. Curious.