The 'Cryptoterrestrial' Paper: What Its Authors Argued

In June 2024, headlines claimed that a "Harvard study" had found aliens might be living among us. The reality is more modest. The source was a speculative paper in the journal Philosophy and Cosmology, written by two researchers linked to Harvard and one at a Montana university. It makes a case for open-mindedness about unusual explanations for unidentified anomalous phenomena (UAP), the official term for UFOs. It presents no new evidence, and the university did not commission or endorse it.

What the paper is

The article is titled "The Cryptoterrestrial Hypothesis: A Case for Scientific Openness to a Concealed Earthly Explanation for Unidentified Anomalous Phenomena." According to the journal's page, it was received on March 12, 2024, accepted on April 22, 2024, and published in volume 33. A preprint circulated online that spring, and the press coverage followed in June.

The authors are Tim Lomas, a psychology research scientist, and Brendan Case, associate director for research, both at the Human Flourishing Program at Harvard, along with Michael P. Masters, a professor of biological anthropology at Montana Technological University. CBS News Boston reported that the paper "is not affiliated with the university," so describing it as a Harvard study overstates its standing.

What it argues

The authors note that explanations for UAP usually fall into two camps: ordinary earthly causes, such as human-made aircraft, or visitors from elsewhere in the universe. They propose giving serious attention to a third, minority category, which they call "ultraterrestrial." Within that category sits the cryptoterrestrial hypothesis: the idea that UAP could reflect the activity of intelligent beings hidden on Earth, perhaps underground or underwater, on or near the Moon, or even passing as humans.

The paper's conclusion sets out four versions of the idea:

• A remnant of an advanced ancient human civilization.
• A non-human terrestrial species, such as an undiscovered hominid or a descendant of dinosaurs.
• Extraterrestrials, or time travellers from the human future, who settled here in secret.
• Beings closer to the "fairies, elves, nymphs" of European folklore, which the authors call "magical" cryptoterrestrials.

The supporting material comes from existing sources: pilot and naval reports of objects said to move between air and water, the 2023 public claims of former intelligence official David Grusch, gaps in the archaeological and geological record, folklore, and secondhand accounts. The claims attributed to an alleged Einstein assistant and a former CIA officer, which circulated in earlier coverage, are among these second-hand stories. None of them has been independently verified.

How seriously the authors take it

The paper is unusually frank about its limits. The authors write that they consider the hypothesis "unlikely" but "not impossible." They say they would once have put its chances at about 1 percent and now put them at about 10 percent, meaning they still judge it nine times more likely to be false than true. They also say it "probably ranks lower" than the extraterrestrial explanation. "We are not arguing that UAP do have a cryptoterrestrial explanation, but simply that they could," they write, and they expect the idea to be "regarded sceptically by most scientists."

Speaking to CBS News Boston, Masters said: "We're not saying this is right, we're not saying that this is absolutely 100% the case." The outlet added that the researchers acknowledge the work is "a speculative thought piece." Later, in a Popular Mechanics interview, Masters described the goal as making "the case for scientific openness" and starting a discussion. Case declined to comment and told the magazine he had "sworn off any further media engagement related to it."

What official reviews have found

The most detailed official review so far points away from hidden or alien technology. In March 2024, the Pentagon's All-domain Anomaly Resolution Office (AARO) released Volume I of its report on the historical record of U.S. government involvement with UAP. It found "no evidence" that any government investigation, academic research, or official review panel had confirmed that a UAP sighting represented extraterrestrial technology. It concluded that most sightings were ordinary objects or phenomena that had been misidentified. AARO also found "no empirical evidence" for claims that the government or private companies had been reverse-engineering extraterrestrial technology. Space.com summarized the findings when the report was released.

The report does acknowledge that some cases remain unresolved. However, it attributes this mainly to poor or limited data, not to anything exotic. AARO assessed that most unexplained cases could be resolved as ordinary if better data were available.

The cryptoterrestrial paper is best understood as a philosophical argument about what scientists should be willing to consider, not as a finding. It offers no physical evidence of hidden beings, and its own authors rate the idea as more likely wrong than right.