The second best thing about space travel is that the distances involved make war very difficult, usually impractical, and almost always unnecessary. This is probably a loss for most people, since war is our race's most popular diversion, one which gives purpose and color to dull and stupid lives. But it is a great boon to the intelligent man who fights only when he must-never for sport.
Robert A. HeinleinBut does Man have any 'right' to spread through the universe? Man is what he is, a wild animal with the will to survive, and (so far) the ability, against all competition. Unless one accepts that, anything one says about morals, war, politics, you name it, is nonsense. Correct morals arise from knowing what man is, not what do-gooders and well-meaning old Aunt Nellies would like him to be. The Universe will let us know - later - whether or not Man has any "right" to expand through it.
Robert A. HeinleinHappiness lies in being privileged to work hard for long hours in doing whatever you think is worth doing. One man may find happiness in supporting a wife and children. Another may find it in robbing banks. Still another may labor mightily for years in pursuing pure research with no discernible result. Note the individual and subjective nature of each case. No two are alike and there is no reason to expect them to be. Each man or woman must find for himself or herself that occupation in which hard work and long hours make him or her happy.
Robert A. HeinleinMen are expendable; women and children are not. A tribe or a nation can lose a high percentage of its men and still pick up the pieces and go on ... as long as the women and children are saved.
Robert A. Heinlein