"Your terms are hardly accurate," said Ashby. "You fail to recognize the fact that we have never known what kind of man it takes to colonize. You ignore the fact that we have never yet successfully colonized the planets of our own Solar System. Bases, yes—but all our colonies have failed to date."
"What better evidence could you ask for in support of my argument?" demanded Winthrop. "We've proved bases are practical, and that colonies are not."
"No matter how far away or how long the periods of rotation, a man assigned to a base expects to return home. Night or day, in the performance of any duty, there is in his mind as a working background the recognition that at some future time he can go home. His base is never his home."
"Precisely. That is what makes the base successful."
Ashby shook his head. "No base is ever successful from the standpoint of permanent extension of a civilization. By its very nature it is transitory, impermanent. That is not what we want now."
"We have the concept of permanent bases in military thinking," said Winthrop. "You can't generalize in that fashion."
"Name for me a single military or expeditionary base that continued its permanency over any extended period of history."
"Well—now—"
"The concept is invalid," said Ashby. "Extensions of humanity from one area to another on a permanent basis are made by colonists. Men who do not expect to rotate, but come to live and establish homes. This is what we want on Serrengia. Humanity is preparing to make an extension of itself in the Universe.
"But more than this, there are limitations of time and distance in the establishment of bases, which cannot be overcome by any amount of training of personnel. Cycles of rotation and distances from home can be lengthened beyond the capacity of men to endure. It is only when they go out with no expectation of return that time and distance cease to control them."