Intelligent Extraterrestrial Beings Do Not Exist

One of the things I love to do is go through old volumes of astronomy journals and read articles that catch my eye. I know, how sad is that?

One of the really cool benefits of doing it though is that I can read over landmark papers first hand, it gives me a feeling of actually being there when important discoveries are being reported.

Earlier today, I was in the astrophysics library at the university and I happened upon a paper in 1980 by Frank Tipler, a proponent of the Anthropic Principle. The title of the paper is Extraterrestrial Intelligent Beings Do Not Exist.

This is not a landmark paper, but it does present an interesting case for the fact that there isn’t anyone out there. I don’t happen to agree with any of it, still it’s nice to get another viewpoint. I found it fascinating.

Essentially, Tipler took Carl Sagan and other proponents of the possibility of ET life head on. Tipler felt that the Anthropic principle (the idea that the universe is fine-tuned for us to exist) and intelligent ET life were unlikely to BOTH be correct, so he set out to prove that there couldn’t be any intelligent life elsewhere in the universe.

Basically, his idea centers on von Neumann machines. These are self-replicating, self-repairing machines that could be build to search for life in the galaxy. These very efficient machines would build copies of themselves at a faster and faster rate until every solar system in the galaxy had one.

An ET civilization could send out these probes, let them self-replicate, and then sit back and wait for the reports to come back. Tipler reasoned that if there were other civilizations, then EVENTUALLY these types of machines would get build by SOMEONE (oh, surely!). Once they were set out, it would take only about 300 million years to occupy every solar system in our galaxy.

Three hundred million years isn’t a very long time compared to the age of our galaxy, this should be plenty of time for these machines to have done their thing by now.

According to Tipler, since there isn’t one of these probes in our solar system (as far as we know), there isn’t any intelligent ET life ANYWHERE.

So there.

[By comparison, I’ve posted before about a study that was conducted using computer simulations and only eight probes. It would take half the age of the universe to only cover 4% of our galaxy searching for ET intelligence that way.]

Tipler had tried to get this paper published twice before, once to the journal Science, where it was sent to Carl Sagan for review because he was the leading expert in the field. Sagan rejected it. The second time it was submitted to Icarus, a journal (unfortunately for Tipler) edited by Carl Sagan at the time. To Sagan’s credit, he sent the paper out to independent reviewers who then rejected it. It was eventually published in the Quarterly Journal of the Royal Astronomical Society.

I know I’m a big nerd, but I recommend just searching through astronomical journals when you can. Most of this stuff is online through the Astrophysics Data System (ADS), an excellent resource. You’d be surprised at what you stumble across.