 This layer too is built in accordance with the principle of minimum mutilation, pursuing its higher goals with as little damage as possible to Respect and Responsiveness.The final layer is the Ethic of Light, the ethic of saints and heroes which builds upon the others by one's becoming a selfless vehicle of goodness.Nozick leaves as an open empirical question whether moral progress with regard to the abolition of slavery, women's rights, the civil rights movement, and gay rights has been propelled by the perception of mutual benefit or the higher layers of ethics.