"Superficially, the cultural level of the natives appeared quite primitive. The absence of tools would normally be indicative. On the other hand, the city was carved from rock in a way so as to suggest a very sophisticated technology. And writing, while apparently not practiced to any considerable extent, was known--or, if not writing as we understand it, some advanced decorative technique. We've found two lines of it, at least. "Again superficially, the city would suggest a nomadic tradition, but for its craftsmanship. It seems independent of any obvious supply of food and their equivalent of water, if any. Nor were any provisions in evidence for the disposal of waste products. Yet the city had the appearance of age and continual usage. If you notice, the floor of the recess was worn unevenly toward the center by what I should guess to be the traffic of several centuries. "The thought naturally occurs that the aliens were the rather decadent relics of a highly developed technological civilization existing on the planet in the not too distant past. Yet Miracastle offers no evidence for the existence of a prior technology--no ruins, no residual radioactivity from atomic operations. In short, the city has no apparent genesis in the past. "The alternative arises: perhaps the natives were not natives at all, but immigrants or colonists like ourselves. Yet the age of the city contradicts this. "Perhaps there is a simple explanation, although it does not occur to me. But I do have this feeling. The city was utilitarian. To me, it calls to mind one of those exquisite etchings of Picasso. The severe economy of line suggests simplicity. Yet, on further inspection, you see that each line contributes to a rather bewildering variety of perspectives. I strongly suspect that the city and the people of Miracastle will remain one of the great, unsolved mysteries of the universe." Mr. Wallace was finished with his remarks. Mr. Ryan nodded. "Perhaps I'm deficient in sensibilities, but I find that the most ... agonizing ... thing of all is not ever to be able to know what these people were like. It's almost as if some part of us had been lopped off, isn't it? What did the people of Miracastle think about? What was their philosophy of life? What was their social organization? What was their ultimate goals? When you realize how much we learned of ourselves from an examination of our own primitive cultures, the sense of loss really comes home. Think how much more we could have learned of ourselves by acquiring the perspective of a truly alien culture. It's almost as if we could really understand ourselves at last if we could only understand a totally alien culture ..." "Well, that's gone," Mr. Tucker said. The words were brittle and discrete. They hung in memory and the listeners waited as though for an echo of something shouted into a canyon. The echo did not come.