الجين الأناني
After being given a copy of Richard Dawkins's "The Selfish Gene" as a Christmas present, in 1978 Mackie wrote an article in the journal "Philosophy" praising the book and discussing how its ideas might be applied to moral philosophy. The philosopher Mary Midgley responded in 1979 with "Gene-Juggling", an article arguing that "The Selfish Gene" was about psychological egoism rather than evolution. This started a dispute between Mackie, Midgley, and Dawkins that was ongoing at the time of Mackie's death.