Person

J.L. Mackie

John Leslie Mackie (1917-1981) was an Australian-born analytic philosopher who spent his career at Oxford. Mackie plays a dual role in the apologetic landscape, which makes him unusually useful in live debate. He is both the architect of the modern logical Problem of Evil and the most rigorous atheist metaethician of his generation. His own conclusion in ethics, moral error theory, is a quiet admission that atheism cannot ground objective morality.

Lifespan and context

Born 25 August 1917, Sydney, Australia
Educated at the University of Sydney and at Oriel College, Oxford
Taught at the University of Otago (New Zealand), the University of Sydney, and the University of York
Fellow of University College, Oxford, from 1967 until his death
Died 12 December 1981, Oxford

Major works

The Miracle of Theism: Arguments For and Against the Existence of God (Oxford, 1982, posthumous). A full atheist engagement with theistic arguments.
Ethics: Inventing Right and Wrong (Penguin, 1977). The foundational text for moral error theory.
"Evil and Omnipotence" (Mind 64, 1955). The standard analytic statement of the logical Problem of Evil.

The logical Problem of Evil

Mackie's 1955 Mind article gave the modern logical POE its form. The claim: (1) God is omnipotent, (2) God is omnibenevolent, and (3) evil exists, taken together, are logically inconsistent. The argument needs an extra premise, that an omnipotent being can actualize any logically possible state of affairs. Alvin Plantinga's Free Will Defense (1974) defeats that premise through the idea of transworld depravity: it is logically possible that every creature, given any genuine moral situation, would go wrong in at least one of them. If so, not even omnipotence can guarantee a world of all-good free creatures.

Mackie himself effectively conceded the force of the Free Will Defense in The Miracle of Theism (1982, pp. 174-176). He admitted that the logical incompatibility he had claimed in 1955 could no longer be shown once transworld depravity was on the table. The philosophical consensus shifted with him. The battlefield moved from the logical POE to the evidential POE (Rowe 1979, Draper 1989).

Codex connections: Problem of Evil, Problem of Evil, Free Will Defense, All-Do-Good World POE Defeater, Evidential Problem of Evil Defeater

Moral error theory

In Ethics: Inventing Right and Wrong (1977), Mackie argued that all moral statements are false. There are no objective moral facts. His argument from queerness says objective moral properties would be metaphysically strange entities, unlike anything else in the natural world. The faculty needed to perceive them would be just as strange.

The apologetic significance. Mackie was the most analytically rigorous atheist metaethician of the 20th century. He examined the options open to atheism and chose error theory, the explicit denial that objective morality exists. He did not take the brute-moral-realism position later defended by Wielenberg, Shafer-Landau, and Enoch. In live debate this is a devastating hostile-witness citation. The atheist's own most careful philosopher concluded that atheism cannot ground morality, and he bit the bullet honestly.

Codex connections: Morality, Moral Argument, Atheist Moral Realism Defeater, Atheist Moral Realism Objection, Subjective Morality Defeater

The dual-role deployment

In debate, Mackie can be used in two directions at once:

Against the logical POE. "Even Mackie, the man who invented the modern logical Problem of Evil, conceded in his posthumous book that Plantinga's Free Will Defense blocks the logical-inconsistency claim. The battlefield moved to the evidential POE because your own side's architect admitted the logical version fails."
Against atheist moral realism. "The most rigorous atheist metaethician of the 20th century looked at the options and chose error theory. He said all moral statements are false. He didn't think brute moral facts could work. So when you tell me you're an atheist and a moral realist, you're taking a position that the sharpest atheist philosopher rejected."

The dual citation puts the opponent in a bind. They must either defend a position Mackie abandoned (logical POE) or defend a metaethical position Mackie rejected (moral realism). Either way they are arguing against their own tradition's strongest thinker.

Mackie and Jack Angstreich

Jack Angstreich's "all-do-good world" argument is a modal-polished update of Mackie's 1955 logical POE. Angstreich deploys the Mackie-style logical-incompatibility claim with heaven as the proof of concept. If God can actualize heaven (an all-good world), why not actualize the present world as all-good? The All-Do-Good World POE Defeater handles this directly through the strong-vs-weak actualization distinction and Plantinga's transworld depravity.