Nonbelievers, What do you believe is sin or wrongdoing, and by who's authority?

I do not believe in sin. I believe in the Five Precepts laid down by the Buddha: one should abstain from taking life, from taking what is not given, from ual misconduct, from false speech, and from intoxicants that cause heedlessness. These are very rational principles; you don't have to be Buddhist to accept them. If everyone followed them, the world would be a better place.