Ethics are not absolute in a sense that they are independent of society; they are an invention of human beings. Every invention has its purpose and the purpose of ethics is to provide a stable standard of interpersonal behavior so that society can function smoothly and people can interact in a productive and cooperative way. Human beings are basically social animals so this fulfills a deep instinct and acts as a survival mechanism (since humans survive better through cooperation). Does this mean that ethics are meaningless?
Mahadevagouda et al. (Wed,) studied this question.