J.L. Mackie was an influential Australian philosopher, best known for his work in ethics and metaethics. Born in 1917, he made significant contributions to moral philosophy, particularly through his argument for moral skepticism, which questions the existence of objective moral values. His most notable work, "Ethics: Inventing Right and Wrong," challenges traditional views on morality and argues that moral claims are not grounded in objective truths. Mackie's ideas have had a lasting impact on contemporary philosophy, influencing debates around moral relativism and ethical subjectivism. He also engaged with the works of other philosophers, including David Hume and Immanuel Kant, to explore the nature of moral judgments and their implications for human behavior.