Theres greatest in terms of skill (Anderson silva/GSP/Fedor etc)
And theres greatest in terms of literally being able to beat anyone else which nearly always comes down to the elite heavyweights (Nog/Fedor/JDS etc)
Its usually GOAT and P4P GOAT as two separate titles.
Why would anyone ever have a GOAT discussion that wasn't P4P? Just wondering where that's the norm, I've never heard it around here