Early religion would have you believe that God guides you by your conscience, but who provided the word of God? God, and the fear of God became a form of government, and the teachings became law. As the world became larger, the words were re-written to create more laws, but taught to people as 'the word of God'. Suppose the written words were completely opposite of what we know today? Suppose we were still guided by Gods instead of Man?
They think they are thinking for themselves and that their morality is objective but thats what everyone else thinks while most of them have to be wrong because of the contradictions. It cant be right for you to murder an innocent person and wrong for you to murder an innocent person. And some say what we call murder is justifiable while we punish people because its "not" justifiable. And as specific as we have to be on the laws the chances of us being right are slim to none.
Our conscience consists of vague reminiscences of precepts heard in early youth which can be proven by the fact that most people have moralities that are congruent with their countries religion except for when that is inconvenient. They use their likes and dislikes to determine what is right and wrong and those are just adaptations to how they were raised. Very few people can think outside of the box long enough to disprove their feelings or consciences validity.
You may act upon your conscience, but whether you do so is up to you, also, I'm bothered by people saying "I wouldn't do That my conscience would bother me" right and wrong isn't decided by your conscience, you're conscience just tells you what it is, accepting it is up to you.
Considering my utter disregard for human life, which is very incongruous with what people seem to think, completely contrary to anything I have been told, I'm going to have to say that's false.
Then again, I honestly believe that people can work together and things won't be shot to hell, so there may be a few issues.