斯蒂芬霍金害怕外星人嗎？

April 30, 2010 -- Stephen Hawking has a warning for humankind. First of all, the celebrated theoretical physicist believes that there probably is alien life out there in the universe. But he doesn’t think we should be trying to make contact with extraterrestrials. Instead, Hawking believes we should be doing everything we can to hide from them.

According to the Times of London, Professor Hawking has a  new documentary  scheduled to be broadcast in May on the Discovery Channel. In that upcoming film, he speculates that one reason aliens might visit us is because they have “used up all the resources from their home planet.” He further imagines that they might treat us much the way Europeans treated Native Americans hundreds of years ago, looking to “conquer and colonize” our watery sphere. “We only have to look at ourselves,” says the Professor, “to see how intelligent life might develop into something we wouldn’t want to meet.”

Now, far be it from me to gloss over the crimes some humans have committed against other humans over the centuries. But Professor Hawking’s pessimism is misplaced for a number of reasons. His fears bespeak a Malthusian misunderstanding of resource economics, an ignorance of the history of violence, and a lack of appreciation of the substantial benefits of voluntary exchange. An examination of Hawking’s errors shows we have every reason to believe aliens capable of crossing interstellar space would be more Mr. Spock than Predator.

MALTHUSIAN FEARS IN SPACE

The Reverend  Thomas Malthus (1766-1834)  famously feared that population growth was doomed to outstrip growth of the food supply, because population grows geometrically while food production only grows arithmetically. But Malthus could not see the explosion of human ingenuity that was coming. Although there are surely some physical limits to how much food we can grow on Planet Earth, we have demonstrated that we can push back against those limits to a large extent. There is more than enough food grown today to feed a world population that is roughly six times what it was when Malthus was writing. It is localized poverty, not planetary lack of food, that still keeps far too many malnourished in this day and age.

Our current fears about the end of oil are misguided.

Our current fears about the end of oil are equally misguided. We value oil not for itself but for what we can derive from it, which is energy. There is a virtually limitless supply of energy beaming down to us in the form of sunlight. We only use oil now because it’s cheaper and more practical, but we could use the sun’s energy more directly if we had to. We literally have a 5-billion-year backup supply of energy to draw from whenever we do run out of cheap, easily accessible oil.

These basic ideas—that human ingenuity pushes back against limits and that different resources can be substituted for one another—seriously undercut the likelihood that nomadic extraterrestrials will conquer and colonize us for our planet’s riches. Aliens capable of deep space travel would clearly have at least as much ingenuity as humans.

IN DEFENSE OF MODERNITY

Even if aliens somehow did “use up” their home planet’s resources, is it really likely that they would travel trillions of kilometers to “conquer and colonize” us for ours? It is true that Europeans did end up taking over after they crossed the Atlantic, and lots of Native Americans ended up dead or dispossessed. What’s more, the newcomers thought nothing of using violence to achieve their goals. For that matter, though, neither did the Native Americans, many of whom were plenty aggressive long before Christopher Columbus set sail.

But believe it or not, a lot has changed in five hundred years. War and murder have not disappeared completely—not by a long shot. Still, as noted professor of psychology Steven Pinker wrote in  a 2007 New Republic article , “Violence has been in decline over long stretches of history, and today we are probably living in the most peaceful moment of our species’ time on earth.” A whole slew of practices that used to be commonplace—among them slavery, virgin sacrifice, torture, and genocide—today are “rare to nonexistent in the West, far less common elsewhere than they used to be, concealed when they do occur, and widely condemned when they are brought to light.”

What about communism and fascism and two world wars? Those were horrible, to be sure. But as Pinker notes, “If the wars of the twentieth century had killed the same proportion of the population that die in the wars of a typical tribal society, there would have been two billion deaths, not 100 million.” Despite all the bad news on the newspaper page, we are becoming more civilized, if only haltingly so.

THE BENEFITS OF TRADE

Why are humans becoming more peaceful? One big reason is that we are increasingly becoming aware of  the great mutual benefits  of trade. War is a negative-sum game, at best an unfortunate necessity in which even the winners lose big. Slavery is not only abhorrent; it’s also a hugely inefficient way of organizing production. People work much harder and smarter when they get to keep the spoils of their efforts. When human beings deal with one another as traders instead of as enemies to be killed or enslaved, everybody is better off. Simply put, you are more valuable to me alive and free than either dead or in chains.

Granted, peace and liberty have not yet carried the day. Not everyone appreciates the importance of economic freedom, and there are times when it seems like we are losing ground. But in the long view, the trend is clearly positive. If we keep on making the principled case for liberty, I am confident that more and more people will come to agree that liberty is both good and right—that the moral is the practical.

Even if extraterrestrials need something from us, we needn’t count on their goodwill for our safety. We can count instead on the rationality that their astonishing technological prowess would require. We can trust that a spacefaring race, far more advanced than we are now, will already have figured out that they have far more to gain by approaching us as traders than as conquerors. In fact, maybe the reason they haven’t dropped in for a visit yet is that they’re waiting for more of us to figure it out too before they make first contact.

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