I can say black is white and white is black all day

Or you can ask the author whether it's black or white -- that'll save you from getting run over.

Method calls are invoked using $instance->method_name().

Agreed.

Foo::new() is calling a fully specified subroutine.

Agreed.

No amount of wishful thinking will ever make that into a method call.

When did I claim that? My point was that it's the author that decides whether a subroutine should be a method or not. When I say method I speak of a subroutine that deals with classes/objects and/or is intended to be inherited/overriden, roughly. I believe that's the common interpretation.

Perl is rather flexible in that it will allow you to call most subroutines either way.

Exactly. The way we choose to call our subroutine doesn't change what the subroutine is. But if we want to call a private method, we can just as well call it directly -- and we should call it directly. See this node.

And strictly speaking (in a computer sciencey manner), there is a specific difference between a procedure and a function

I'm familiar with that from Pascal... But Perl makes no difference. In Perl there's no technical difference between methods, functions, and procedures; they're all subroutines. We are discussing Perl's object model, are we not?