I think that whatever may be the principle she was describing, this word phototropism was merely the nearest thing to it in my reservoir of language. If I did know the physical principles which brought them here, and could write them in terms accessible to technicians, I would not do it. Here is a thing I am afraid no hypothetical reader of this journal would believe: These people, as I have written, learned their method of space travel some twelve million years ago, yet this is the first time they have ever used it to convey them to another planet. The heavens are rich in worlds, she tells me; on many of them there is life, often on very primitive levels. No external force prevented her people from going forth, colonizing, conquering, as far as they pleased. They could have populated a whole Galaxy. They did not, because they believed they were not ready. More precisely-- _Not good enough!_ * * * * * Only fifty million years ago, by her account, did they learn, as we may learn eventually, that intelligence without goodness is worse than high explosive in the hands of a baboon. For beings advanced beyond the level of Pithecanthropus, intelligence is a cheap commodity--not too hard to develop, hellishly easy to use for unconsidered ends. Whereas goodness is not to be achieved without unending effort of the hardest kind, within the self, whether the self be man or angel. It is clear even to me that the conquest of evil is only one step, not the most important. Goodness, she tried to tell me, is an altogether positive quality; the part of living nature that swarms with such monstrosities as cruelty, meanness, bitterness, greed is not to be filled by a vacuum when these horrors are eliminated. Kindness, for only one example. Anybody who defines kindness only as the absence of cruelty doesn't understand the nature of either. * * * * * They do not aim at perfection, these angels, only at the attainable. They passed through many millenia while advances in technology merely worsened their condition and increased the peril of self-annihilation. They came through that, in time. War was at length so far outgrown that its recurrence was impossible, and the development of wholly rational beings could begin. Then they were ready to start growing up, through more millenia of self-searching, self-discipline, seeking to earn the simple out of the complex, discovering how to use knowledge and not be used by it. Even then, of course, they slipped back often enough. There were what she refers to as eras of fatigue. In their dimmer past, they had had many dark ages, lost civilizations, hopeful beginnings ending in dust. Earlier still they had come out of the slime, as we did. But their period of deepest uncertainty and sternest self-appraisal did not come until twelve million years ago, when they knew a Universe could be theirs for the taking, and knew they were not yet good enough.