This is a question for atheists and humanists...
No, that was 8 questions.
Where do you get your ideas about what is right and what is wrong from?
Same place you and everyone else gets their morals from; society, upbringing, empathy, discourse, contemplation, research, evidence and reasoning.
People have different upbringing though, live in different communities, have different degrees of empathy and reasoning capabilities, so that is why we can't all agree.
Who gets to decide this for society?
We all do. Society has shaped us, but we also have the ability to improve it for future generations.
What's makes your morality more moral than mine?
Wether mine is better would depend on what your moral views are. I judge moral actions based on what benefit and harm they have in society. If you cause deliberate, unnecessary harm, I'm more moral than you.
Where does the conscience come from?
We evolved to be a highly social animal, and empathy and a conscience are integral parts of this. Kin selection and policing can also help to explain part of this. But it's a complicated question to answer, and I doubt anyone has a full, satisfactory answer. And no, "God-did-it" isn't satisfactory either.
Whose to decide who's conscience is 'correct'?
I do. Just as you decide that yours is correct. The next step is to have a discussion and try to come to an agreement. Perhaps you can convince me that on a certain point you are correct, and I will amend my views.
What's to stop the 'elite' deciding that, under 'survival of the fittest', they are more than justified to dominate the rest of us?
I, and people like me, who oppose tyranny, will stop them.
Though my first effort would be to try to explain to them how they have misunderstood the phrase "survival of the fittest". Fitness in evolution has to do with number of viable offspring. If anyone truly wanted to live by that phrase, they would try to have as many children as they possibly could.
Why does every society under 'humanism' decay (and yet the Judeo-Christian ethic remains as strong as ever)?
It's the other way around. Our societies have improved greatly due to humanistic efforts. We've outlawed slavery, even though it's promoted in the Bible. Genocide is considered the worst of crimes, despite the god of the OT having a fondness for it. Witch burning is long gone, despite being prescribed in the Bible. Read a history book and you will discover how cruel the world was when Christianity was in charge, even though they used the same scripture then as they do now. So obviously morals can't just come from scripture. Humanistic values have dragged Christianity kicking and screaming into the 21th century.
Isn't the logical conclusion of a 'humanist' society built on the principles of Darwinism, one of domination by a dictatorial elite?
No. It would be absurd to suggest that society should be based on a natural science theory. How would one go about building a society on the principles of the theory of gravity? Make laws against balloons and rockets?
Darwinian evolution is based on observations in nature and has nothing to do with building societies. Likewise, just because we observe in nature that some spiders eat their mating partners after copulation, doesn't mean that we should apply it to human society.
Anyway, the theory is about alleles in a gene pool changing in frequency due to natural selection, sexual selection, kin selection, genetic drift, gene flow etc. Even if one was insane enough to want to build a society based on that, there'd be no way to do it.
Peter