Fear of Aliens

Renowned physicist Stephen Hawking recently expressed the idea that one ought to fear aliens. Here is the key passage in the Times article on his Discovery Channel show:

He suggests that aliens might simply raid Earth for its resources and then move on: "We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach."

He concludes that trying to make contact with alien races is "a little too risky". He said: "If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the Native Americans."

The fallacy in this otherwise brilliant man's idea is clear. "We only have to look at ourselves to see how intelligent life might develop..." assumes that alien life is not alien. It is of course rational to base our concepts on how intelligent life MIGHT behave on the only clear example we have, the one on which we base all our concepts of intelligence — humanity. But to then say that aliens might develop like us ignores the very mathematical brain he cites earlier:

"To my mathematical brain, the numbers alone make thinking about aliens perfectly rational," he said. "The real challenge is to work out what aliens might actually be like."

The numbers alone should make thinking about aliens also factor in the likelihood that aliens are extremely unlikely to be anything like us. But there are also a few other statistics that should be of importance: for example, given that we have encountered no recognizable trace of alien life so far, inductive reasoning should hold that there is no such thing as alien life in a form that we can recognize as such.

It is similar to the statistical idea here: the longer we exist, the more we are certain that a) humans are the only humanly-defined human-level intelligence around, and b) life only exists on our planet. How can that be? Surely the laws of probability must dictate that there is other life elsewhere?

Actually, here we run aground on the rocks of infinity, so to speak. In theory, anything is possible in an infinite universe. However, if there are any universal laws at all, this constrains certain events from happening; and empirically speaking, the 'certitude' that anything is possible does not mean that any specific thing has indeed occurred. It is unthinkable to some scientists that alien life does not exist, but that is the triumph of imagination over intellect (Einstein's definition of love, actually).

Here's another point to ponder: in an infinite universe, there can be an infinite number of intelligent alien races — but in an infinite universe, the 'quarantine distance' between them might be too great to overcome. Perhaps they are all out there, but too far away, like individual colonies of sulfur-loving bacteria near ocean vents, that will never ever meet members of other colonies.

I don't fear aliens. But I love cats, and fear sharks. I am neutral towards dogs in general, and dislike many kinds of insects. The chances that these biases will affect my future transactions with (for now) imaginary aliens are statistically nil in an infinite universe. Think about what that might mean.