Conscience

Have you ever wondered if there's an ultimate right and how do you differentiate it from the wrong? Which is the absolute right? Or should I ask, who holds the last say to which is right and which is wrong? I guess it all boils down to your own conscience. We normally will perceive the right to our own interest. At the end of the day, if it is to our liking and benefits ourselves, then that will be the ultimate right.