John Carter McKnight recently wrote an article on the rights of Martian lifeforms, should they turn out to exist.

The question arises because, unlike the search for extraterrestrial intelligence, we haven't yet reached any consensus on a protocol for how to respond if we discover non-intelligent extraterrestrial life, particularly a physical discovery in our own solar system that could be adversely affected by such a discovery (though people are working on one).

While we may not want to go to the extremes of Star Trek's Prime Directive, which forbids contamination of another culture with technologies that are beyond it, or knowledge of other species on other planets, it can provide a useful starting point for dealing with other sapient beings. We would presumably treat them differently than non-sapient beings, for the same reason that we make a distinction on earth between humans and other animals. The former are moral agents, and the latter are not.

What, then, should be the basis for developing an ethic with respect to unearthly non-sapient beings?

McKnight lists three broad philosophical perspectives.

• Preservation: the belief that humans should minimize their actions in nature. (The Prime Directive is one example of this)
• Stewardship: a human-centered, utilitarian approach. Stewardship sees humans as the only moral objects, with nature as resources and objects rather than as moral agents with their own rights. Such a view is often biblically based.
• Intrinsic Worth: the notion that humans are not the only creatures with rights and moral standing--that others are equal to humans in the eyes of moral law.

Our current terrestrial environmental policies (at least in the United States) are based on a combination of preservation and stewardship. The Endangered Species Act is an example of the former, while the federal policies for logging and ranching are of the latter. The policy has to maintain a balance between these conflicting views, and the current debate about how much forest thinning to allow, in order to prevent devastating wildfires, is an excellent example of the continual tension between them.

Intrinsic worth doesn't inform much public policy, but it's the position of the more radical (and in some cases, terrorist, perhaps because they've been so unsuccessful in getting their views implemented into law) environmentalist movements, such as Earth First. These people are often called deep ecologists, many of whom believe not just that man is of equivalent moral standing with other animals, and even all other living things, but perhaps of lower moral standing. Indeed, some of them consider humanity a cancer on the face of the universe, that needs to be quarantined to this planet, if not exterminated entirely, for the benefit of the rest of nature.

Now, suppose that we find, via either a robotic probe, or a human mission, that Mars (or, some other possible locations, such as Jupiter's moon Europa or Saturn's moon Titan) has some sort of primitive life form, such as bacteria or lichen? What is the implication of each of these points of view for how to treat such life?

The intrinsic worth position would be pretty simple--we had no darned business sending those robots out there in the first place--they might contaminate the ecosystem and destroy it.

But assuming that such a view will be as politically untenable in space as it has proven on earth, likely the policy would be, like here, some combination of preservation and stewardship.

It's probably possible to establish human settlements on Mars without destroying the indigenous lifeforms, as long as they are sealed apart from the environment (necessary to support human life anyway, given the fact that the atmosphere of the planet is so thin as to mimic a vacuum, as far as human lungs are concerned). As long as we don't take along any bugs that are particularly well suited for the natural Martian environment, it's unlikely that earthly life will be able to outcompete life that evolved there. So both goals can be accomplished under those circumstances.

But if we get to the point at which we want to "terraform" the planet, to provide it with a breathable atmosphere, it will prove a death knell for anything living there now, just as the early life forms on earth were wiped out by more advanced forms that created our present oxygen atmosphere, which proved toxic to them. The only way to satisfy the preservationist ethos would be to take the existing flora and fauna, and put it into the equivalent of a zoo, to at least preserve the species.

I would like to propose a possible fourth perspective, based on an interesting recent theory that the universe may have a teleology, or purpose. The proposition is that intelligent life created the universe, and will ultimately help it reproduce itself. Even more controversially, it may be that things can somehow "wrap around" such that we may have reached back in time from other universes to create the one in which we live.

As someone who is not religious in the conventional deistic sense, I can't say whether it's scientifically true, but I find it at least a comfortable belief. One of the purposes of a religion is to provide meaning to existence, beyond sitting around chugging beer and watching football. To me, being a part of the process by which the universe attains self awareness and fulfills its ultimate destiny seems as good a goal to which to hitch one's fate as any.

In this formulation, it is not just our right, but our duty to take such actions as to increase the amount of intelligent life in the universe, and expand consciousness throughout. This means carrying the flame of life beyond the earth, bringing life to the sterile places, and creating new ecosystems first throughout the solar system, then out into the galaxy, and ultimately beyond.

But what happens when we encounter another ecosystem? Well, it depends on whether it's intelligent (and particularly, if it's conscious) or not.

If it is (assuming it's not hostile), we can leave it to do its bit to satisfy the goal, and move on to virgin territory.

But if it's not, then it has no special claim to existence, or the territory in which it evolved. In the interests of the preservation of knowledge, the ecosystem will be preserved, but its range may be vastly limited in order to carry out the higher purpose. Think of it as "Manifest Destiny" not for white men, but for intelligent life and perhaps the universe itself.

And let's face it, these rock candy mountain ideas are only workable in an environment where there's an agency available to enforce them that's also willing to do so. Once we get to a point where private groups are able to move out on their own and survive there'll be precious little anyone's likely to be able to do to enforce these viewpoints. This to me is a feature, not a bug but others will disagree. Anyone care to take bets on governments attempting to prevent autonomous groups from leaving their sphere of influence once the technology permits?

I agree, how can any philosophy govern how people behave 40 million miles from Earth, especially if you have independent private groups/companies undertaking this endeavor? And how could a government that's signed the Outer Space Treaty enforce it?

The more I've learned about the limits of enforcement capability even in a closed bubble like the earth, the more I find utterly laughable the notion in so much popular science fiction of a single imperial or bureaucratic authority that can impose its will across an entire galaxy.