Hart: There is no ETI therefore there should be no SETI

Hart (1975) is about asserting why the author believes that there are no other intelligent civilizations in our galaxy. That essentially makes this paper about addressing the Fermi Paradox.

The entire article is written about refuting different explanations for the fact that “there are no intelligent beings from outer space on Earth now”, which he puts into four categories: physical, sociological, and temporal as well as those that say that we have been visited, but the visitors are no longer here.

The paper makes its case by attacking each type of explanation individually. Physical explanations are refuted by providing some examples of future possibilities for long distance space travel and saying a sufficiently advanced civilization could figure it out. Sociological explanations aren’t valid unless they apply to all civilizations for the entirety of their existences. Temporal explanations are addressed by stating that it would be a mighty coincidence that a galaxy colonizing civilization evolved less than a million years ago (<0.1% of our galaxy’s age). The last category is address with a mixture of arguments from the temporal and sociological section.

Finally, anyone saying that the main fact is actually false and that aliens are here is wrong because few astronomers believe that. This point is added on at the end and I find it childish. I don’t really see the point of bringing up the possibility of the main fact being wrong if it is not going to be properly addressed.

This paper is interesting because it is the first paper that is openly against spending resources on SETI.

I feel like the paper takes a lot of logical liberties in order to make its point. Importantly, his conclusion is that there are no intelligent civilizations in our galaxy, and I think he means currently. When he makes his arguments against sociological explanations, he talks about how cultures change over millennia, so any intelligent civilization would eventually start venturing out to find us, but a critical point he never mentions (at any point in the paper) is that we don’t know how long intelligent civilizations last. A lot of his arguments (eventually their technology will advance, their cultures will change, their colonization borders will grow) fall apart when dealing with technological civilizations that only last a thousand years or so.