Through all of our history we have pondered the stars and mused whether humanity is unique or if, somewhere else in the dark of the night sky, there are other beings who contemplate and wonder as we do, fellow thinkers in the cosmos. Such beings might view themselves and the universe differently. There might be very exotic biologies and technologies and societies. In a cosmic setting vast and old beyond ordinary human understanding, we are a little lonely, and we ponder the ultimate significance, if any, of our tiny but exquisite blue planet. The search for extraterrestrial intelligence is the search for generally acceptable cosmic context for the human species. In the deepest sense, the search for extraterrestrial intelligence is a search for ourselves. Along with the growing dedication to a serious search, a slightly negative note has merged which is nevertheless very interesting. A few scientists have lately asked a curious question: if extraterrestrial intelligence is abundant, why have we not already seen its manifestations?

　　解析：

　　贯穿我们整个历史，我们一直在考察星星，思考人类是否是唯一的高级生命，还是也许在黑暗的夜空某一处，还有其他生命，宇宙中同辈思想家，也和我们一样在思考，在怀疑。这类生命可能不同于我们看待他们自己和宇宙。那里也许会有异乎寻常的生物学、技术和社会。在这人们难以想象的广袤而古老的宇宙苍穹中，我们是有点孤寂：我们思考着我们小而精微的蓝色星球的最终意义，假如有意义的话。探索外星智能就是为人类探索能接受的宇宙渊源背景。从深层意义上说，探索外星智能就是探索我们自己。最近，有一些科学家提出一个难以解释的问题：如果外星智能很多，那我们为什么没有看出其表现的形式呢?