J. L. Mackie
Notes
John Leslie Mackie (1917–1981), Australian philosopher who spent most of his career at Oxford. Ethics: Inventing Right and Wrong (1977) opens with the sentence "There are no objective values" and defends it with the "argument from queerness": objective moral facts would be entities utterly unlike anything else in the universe, known by a faculty utterly unlike any other, and the simpler explanation is that there are none. The Miracle of Theism (1982) is one of the best philosophical cases against the existence of God.
Wikipedia: https://en.wikipedia.org/wiki/J._L._Mackie