It was on the final pages of Reasons and Persons that Parfit posed an arresting hypothetical. Consider, he said, three scenarios:
(1) World peace.
(2) A nuclear war that kills 99 percent of the world’s population.
(3) A nuclear war that kills 100 percent of the world’s population.
Clearly, he observed, (2) is worse than (1), and (3) is worse than (2). But which is the greater of the two moral differences? Most people, Parfit guessed, would say the difference between (1) and (2) is greater than the difference between (2) and (3). He disagreed. “I believe that the difference between (2) and (3) is very much greater,” he wrote. Killing off that last one percent, he observed, would mean destroying the entire future of humanity—an inconceivably vast reduction in the sum of possible human happiness.
Writer - Critic - Poet - Editor