Another problem is that there can be any number of pathnames, including zero pathnames. We get newbie admins all the time who encounter a filled filesystem, locate a large file, and simply run "rm large_file" without checking to see if the file is open. And then they wonder why the space was not freed.
But this situation could be intentional too. Lots of programs open a temporary file, unlink it, and then use it. This results in very good security since no other program can access that file. And it arranges for the file to automatically disappear when the program exits.
Also be aware that there can be many pathnames as well. Your question seems to imply an assumption of exactly one pathname per file. Filesystems don't work that way in unix.