J. L. Mackie

John Leslie Mackie was a highly influential Australian philosopher.

He made major contributions to several complex fields. These included ethics, the philosophy of religion, metaphysics, and the philosophy of language. His work is often categorized as analytic philosophy. This approach relies on using very clear and logical reasoning. Mackie was known for his significant views on metaethics. He also provided a sophisticated defense of atheism. His reputation was such that Time magazine called him one of the ablest atheistic philosophers of his time.

In the field of metaethics, Mackie proposed a position known as moral skepticism. He argued against the existence of objective values. In his 1977 book, Ethics: Inventing Right and Wrong, he stated that there are no objective values. He believed that ethics must be invented by humans rather than discovered in the world. He used a concept called the Argument from Queerness to support this. This argument suggests that if objective moral values existed, they would be very strange entities. He believed we would need a special faculty, like intuition, to know them. Mackie also held a view called error theory. He argued that while moral judgments are cognitive, they are all false because no moral properties actually exist.

Mackie also explored the philosophy of religion. He was a vigorous defender of atheism. He famously argued that the problem of evil makes monotheistic religions untenable. He believed that the existence of evil and suffering is incompatible with an all-powerful and all-good god. In 1955, he published "Evil and Omnipotence" to summarize this view. He argued that belief in such a god is positively irrational. This specific argument prompted the philosopher Alvin Plantinga to create the "free-will defense." Mackie later addressed this in his posthumously published book, The Miracle of Theism. This work is considered a tour de force in contemporary analytic philosophy.

In metaphysics, Mackie studied the nature of causality. He analyzed how one event causes another. He developed a theory based on counterfactual conditionals. He introduced the concept of an "INUS condition" to explain this process. An INUS condition is an insufficient but non-redundant part of a condition. This condition is itself unnecessary but sufficient for an effect to occur. For example, a short circuit might be part of a fire condition. The short circuit is necessary for that specific fire, but not sufficient on its own. However, the combination of the short circuit and flammable material becomes sufficient for the fire. Other things, like lightning, could also cause a fire.

Mackie's life began in Killara, Sydney, on August 25, 1917. His father, Alexander Mackie, was a professor of education. His mother, Annie Burnett, was a schoolteacher. Mackie attended Knox Grammar School, where he was named dux.

He graduated from the University of Sydney in 1938. He later studied at Oriel College, Oxford, earning first-class honours in 1940. During the Second World War, he served in the Royal Electrical and Mechanical Engineers. He served in the Middle East and Italy and was mentioned in dispatches.

His academic career spanned several countries and prestigious institutions. He taught at the University of Otago in New Zealand from 1955 to 1959. He returned to the University of Sydney as the Challis Professor of Philosophy from 1959 to 1963. In 1963, he moved to the United Kingdom. He became the first holder of the chair of philosophy at the University of York. Later, he was elected a fellow of University College, Oxford. He also became a fellow of the British Academy in 1974. He died in Oxford on December 12, 1981.

Philosophy often becomes a family tradition for the Mackies. He married Joan Meredith in 1947. Their daughter, Penelope Mackie, was also a philosopher who lectured at several universities. His son, David, is a philosopher and the Head of Philosophy at D'Overbroeck's College, Oxford. His daughter, Hilary, is a classicist at Rice University. Mackie was also known for his personal character. He could express total disagreement in a very genial way. People sometimes mistook his disagreements for compliments because of his polite style.