In this article, we reflect on the motives underlying the search for extraterrestrial intelligent life (SETI) with a view to show that far from turning away from humanity it is profoundly rooted in human aspirations. We suggest that those motives derive their driving force from the fact that they combine two powerful aspirations of humanity. On the one hand, there is the transcendental motive that drives history of science, the human enterprise that claims to escape any communitarian closure of horizon and brings our humanity to transcend itself toward the other, which was formerly referred to under the title Universal Reason. On the other hand, there is the anthropological motive by virtue of which the human being tends to project on the other and even in inanimate nature a double of himself. The mixture of both motives is deemed responsible for a remarkable bias in the current understanding of the SETI programme. Despite the fact that such a programme might well be aimed at any biological formation which could be arbitrarily different from all known forms, it is focused instead on a very special kind of being: beings that possess both the natural property of the type of mentality we identify with: intelligence, and the ideal one of being possible co-subjects for a Science of Nature.