He's Viewing Extraterrestrials Through Rose-Colored Glasses

The cosmologist Ethan Siegel has a new post in which we once again see a scientist passing off some dubious armchair reasoning as “science.” The post is entitled, “Afraid of Aliens? The Science Doesn't Back You Up.” Siegel argues that we have nothing at all to worry about if extraterrestrial spaceships arrive in our solar system. He states:

For a species to come as far as an intelligent, spacefaring alien would have come, they must have figured out a solution to a whole slew of problems that humanity clearly still grapples with. Meeting a civilization such as this could only have positive outcomes for our own.

Oh really, Ethan? But what about if visiting extraterrestrials want to conquer us, enslave us, exterminate us, or vastly reduce our numbers, putting the few remaining humans in zoos or reservations? The idea that science backs up the claim of friendly extraterrestrials is rather laughable. Science consists of what we have observed. The only things that are arguably observations of extraterrestrials consist of a wide variety of people reporting alien abductions that were usually not very pleasant. You could argue with just as much force that the empirical evidence suggests we should be afraid of extraterrestrials.

Below is some of Siegel's reasoning on this matter:

If they were hostile to humans, or indifferent to our lives but interested in something present on our world, there might be no way at all to save ourselves. It might be humanity's demise. That's exactly the fear that many among us possess. But is that fear based in reality, and is that a legitimate reason to not send our messages, spacecraft, and information to the stars beyond our reach? Absolutely not.

So extraterrestrials might cause our demise, but this is “absolutely not” a reason we should worry about sending out messages announcing our existence, messages that might attract visitors? That doesn't make sense.

Siegel paints this rosy picture of human contact with extraterrestrials:

The possible benefits to humanity of making contact are immeasurable. It would be like receiving a great galactic teacher, advanced thousands of years beyond our own scientific and technological capabilities. It would be the ultimate cultural exchange ever experienced on Earth.

There is no logical or scientific basis for concluding that arriving extraterrestrials would be like benevolent teachers. Scientifically speaking, the only evidence we have relevant to such a matter is evidence from history in which visitors from one civilization arrived on distant shores to discover some very different civilization. This has almost never been a pleasant case of benevolent teachers arriving, and has often been a case of the arriving civilization having a deadly impact on the civilization it visited (as in the case of the Conquistadors arriving in Mexico and Peru). 

Given the age of the universe, if we were to receive benevolent extraterrestrial visitors, it seems likely that they would be so vastly more advanced than us that they would have little interest in playing "great galactic teacher" to us -- just as a tenured college professor has little interest in teaching multiplication tables to little first-grade children.

Given the seemingly miraculous luck needed for life to originate, there is reason to suspect that life may be very rare in our galaxy. So imagine if a spaceship from another planet arrived here, after a very long journey in which no life was found. The visitors would probably regard our planet as a very rare wonder, like some oasis swimming pool in the middle of the Sahara desert. So they might well think: let's end our space voyage, stop right here, and make this planet our new home. Having decided that, their next steps might be:

1. Vastly reducing the human population, freeing up the planet for their own colonization.
2. Confining the remaining human population to reservation areas, similar to the Indian reservations set up in the US.
3. Removing most human buildings, preserving a few as historical reminders of the past.
4. Terra-forming the planet so that it became more like their own planet, which might involve lowering or raising the temperature, or increasing or decreasing the oxygen levels.

After they were finished, the map of the eastern United States might look like the one below, with all of the non-circled areas being bulldozed areas reserved for colonization by extraterrestrials.