In the Marvel film “Avengers: Infinity War,” Thanos, a superbeing from another planet, is seeking six gems — the Infinity Stones — to put into the Infinity Gauntlet, a weapon which, when completed, enables the one who wears it to extinguish half of all life in the universe with just a snap of his fingers.

Thanos is cast as a supervillain, but he thinks of himself as an altruist. He explains to another Marvel character, Dr.… Continue Reading