Exiled from Earth, they traveled in crude starships on the first wave of colonization from Earth. With the aid of their robots, the Spacers terraformed fifty worlds and created a culture of great beauty and refinement, where all unpleasant tasks were left to the robots. Ultimately, virtually all work was left to the robots. Having colonized fifty planets, the Spacers called a halt, and set themselves no other task than enjoying the fruits of their robots’ labor.

The Settlers were the descendants of those who stayed behind on Earth. Their ancestors lived in great underground Cities, built to be safe from atomic attack. It is beyond doubt that this way of life induced a certain xenophobia into Settler culture. That xenophobia long survived the threat of atomic war, and came to be directed against the smug Spacers—and their robots.

It was fear that had caused Earth to cast out robots in the first place. Part of it was an irrational fear of metal monsters wandering the landscape. However, the people of Earth had more reasonable fears as well. They worried that robots would take jobs—and the means of making a living—from humans. Most seriously, they looked to what they saw as the indolence, the lethargy and decadence of Spacer society. The Settlers feared that robots would relieve humanity of its spirit, its will, its ambition, even as they relieved humanity of its burdens.

The Spacers, meanwhile, had grown disdainful of the people they perceived to be grubby underground dwellers. Spacers came to deny their own common ancestry with the people who had cast them out. But so, too, did they lose their own ambition. Their technology, their culture, their worldview, all became static, if not stagnant. The Spacer ideal seemed to be a universe where nothing ever happened, where yesterday and tomorrow were like today, and the robots took care of all the unpleasant details.