And we've got to completely merge our nationalist feelings in these space accomplishments. In other words, every space settlement has to be international in origin, international in population. Anything we do which can wipe out the feeling of nationalism on earth and increase the feeling of planetary humanism is for the better. It's extremely difficult to do, because we all have our ingrained prejudices and our backward ways of thought, but we've got to anyway. No, science can't ever be finished.
Science fiction stands in the present and looks towards the future.
If you can imagine someone tied to the front of a railroad locomotive, just the fact that the train moves forward doesn't mean that he can no longer look forward, he just has a better vision from a different point. Each time science makes a new discovery, it invents plots for us, new plots, better plots that we wouldn't ever have been able to think up by ourselves if science didn't help out. We've lost the canals on Mars, we've got volcanoes. We know there are no living things on the moon, though we know that there are also glassy particles on the moon, and that gives us ideas for further stories, and so on.