Major modern philosopher who defended moral skepticism and expanded metaphysics.
He studied at Oriel College and served with the Royal Electrical and Mechanical Engineers during World War II.
His best-known tome was Ethics: Inventing Right and Wrong in which he stated "There are no objective values." It was one of six books he published.
He was the son of Annie Burnett Duncan and Alexander Mackie.
He believed that the ideas in the book titled The Selfish Gene by Richard Dawkins could be applied to moral philosophy.