When I was a young Catholic, we heard a lot about "the natural law." The natural law was the reason we were not permitted to use contraceptives, for example. Humans were not created by God with a packet of condoms in their pockets, and therefore contraceptives are unnatural and morally wrong. I never quite grasped the concept. If condoms are unnatural, what about penicillin? iPods? Popemobiles? We were urged not to think about it too much and leave it up to the moral theologians to decide what is natural and good, or artificial and evil.
The natural/artificial dichotomy continues to haunt our ethical lives. Is the genetic engineering of crops and animals natural or artificial? What about modification by selective breeding? Is human cloning immoral because it is unnatural? Is same-sex marriage unnatural? Can a sufficiently intelligent machine have moral rights? Is it morally permissible to "artificially" extend human lifetimes, perhaps even eliminate senescence altogether?
In all of these issues, the age-old distinction between natural and artificial lurks with a vexing tenacity. Even when not explicitly evoked, it remains embedded in our language and patterns of thought. I would submit that it is no longer useful as a guide to ethical action. For example, Roman Catholic opposition to contraceptives in the face of the AIDS pandemic in Africa may itself be deeply immoral.
The natural/unnatural distinction as a basis for ethics had its origin at a time when the world was understood in the dual categories of nature/supernature, body/soul, matter/spirit. These dualities have been shown to be elusive, yet we still try to organize our lives as if they have relevance. In the coming century, natural/artificial distinctions will become increasingly difficult to maintain. It is time to lay a basis for ethics that makes no reference to "natural law."
(Tomorrow: One last meditation on this theme.)