Originally posted by Archaeopteryx
One is biologically an adult when they can reproduce their own species. In human terms one is legally an adult when they can engage in contract. When a human is emotionally an adult is open to interpretation.
I tend to agree with what you've stated, here. I see the concept of an "adult" to be much more nebulous than most people prefer. As I've stated, some people never reach a point, in their life, to where they can give informed concent in a semi-complex social contract. Still, others reach maturity much sooner than others and have the understanding and ability of even very capable adults.
There was someone like that on KMC a few years back. No way you could have guessed he was 14...trying to remember his name. Sure, a forum is not the best of ways to assess a persons social abilities, understanding, bla bla bla. But it can certainly give you an idea.