"They arise, as marriage customs always do, from economic necessities of the circumstances—and our circumstances are very different from those here on Earth. Take the line type of marriage which my colleague has been praising . . and justifiably, I assure you, despite his personal bias—I am a bachelor and have no bias. Line marriage is the strongest possible device for conserving capital and insuring the welfare of children—the two basic societal functions for marriage everywhere—in an enviroment in which there is no security, neither for capital nor for children, other than that devised by individuals. Somehow human beings always cope with their environments. Line marriage is a remarkably successful invention to that end. All other Lunar forms of marriage serve that same purpose, though not as well."