Sir: John Walsh thinks it ludicrous that organised religion should bother itself about whether or not concepts of sin and salvation might apply to any intelligent non-human species the universe may happen to contain. ("I say there, are you absolved?", 31 August).

The concern is not, as he appears to believe, new. Some of the best science fiction stories written this century, like James Blish's "A Case of Conscience", have explored just these questions. But in any case, Mr Walsh's desire to poke fun at clerical small-mindedness misses the point. To ask how other intelligent species might relate to Christ is not to look for potential new (if oddly shaped) bums on pews. It is to ask whether the values which give meaning to human existence, and which have been embodied for our culture in the story of Jesus - love, trust, truth-telling, compassion, forgiveness, self-sacrifice - have universal validity. If there are other minds and hearts out there, do they suffer as we suffer, hope as we hope, and if so, might we one day try to understand and befriend each other?

Christianity is built on the premise that, despite the bloodiness of experience and the miseries we endure, life is worth living, because our faltering loves and attempts at virtue are not self-deception, but a reflection of the fundamental structure of reality, what Dante called "the Love that moves the Sun and the other stars". That may of course be a mistake, but it is neither silly nor ignoble. I have no idea whether or not we are alone in the Universe: but if we are not, is it really so foolish to hope that such thoughts may have occurred to other minds, and that we might find more in common with living beings from other worlds than is suggested by the hateful clawed monster in the picture chosen to illustrate Mr Walsh's article.