Necessary Thing

[robvalue]

By observation, that would appear to be a reasonable conclusion, yes. Even if we go outside of observable reality, we've only claimed that some things follow the rule, so it doesn't matter what happens in the rest of reality.

The only way it could be wrong is if our current understanding is flawed. So I'll happily say that one is fine, for the sake of argument.

The extrapolation comes when you make a general statement that is always true, or a conclusion that would require more information than we can possibly get.

For example, if I said objects are always affected by gravity, that would be an extrapolation. I don't know if gravity continues to apply outside of what I can test; even less so outside of our reality (if such a thing is coherent).

The biggest problem here, that I can see coming, is what exactly constitutes a "thing".