> There's no discernible difference between p-zombies and 'real' conscious beings. There's a good chance that we're all p-zombies and a distinction between zombie and real doesn't exist.

I think you're getting it wrong. There's no externally discernible difference between a normal person and a p-zombie, because the difference is in how they experience. I know I'm conscious, because I subjectively experience it, but I can't be sure about anyone else because they could be a p-zombie that has everything except that subjective experience.