Asked to describe a world in which he would like to live, a man will often refer directly to reinforcing conditions—freedom from aversive stimulation and an abundance of positive reinforcers—but he then finds himself unprepared for many paradoxes, such as the often encountered unhappiness of those “who have everything” or, in that other field of utopian speculation, man’s failure to conceive of an interesting heaven. (p. 64)
