The Ethical Dimensions of Space Settlement.

While proposals for settling in the space frontier have appeared in the technical literature for over 20 years, it is in the case of Mars that the ethical dimensions of space settlement have been most studied. Mars raises the questions of the rights and wrongs of the enterprise more forcefully because: (a) Mars may possess a primitive biota; and (b) it may be possible to terraform Mars and transform the entire planet into a living world. The moral questions implicit in space settlement are examined below from the standpoints of four theories of environmental ethics: anthropocentrism, zoocentrism, ecocentrism and preservationism. In the absence of extraterrestrial life, only preservationism concludes that space settlement would be immoral if it was seen to be to the bene"t of terrestrial life. Even if Mars is not sterile, protection for Martian life can be argued for either on intrinsic or instrumental grounds from the standpoints of all of these theories. It is argued further that a strict preservationist ethic is untenable as it assumes that human consciousness, creativity, culture and technology stand outside nature, rather than having been a product of natural selection. If Homo sapiens is the "rst spacefaring species to have evolved on Earth, space settlement would not involve acting &outside nature', but legitimately &within our nature'.