Doubt as a principle in science
In an article for the journal Acta Astronautica ESA employee Philippe Ailleris has examined the history of research about unexplained atmospheric phenomena. He is concluding: "For this reason it could be said to be essential not only to keep Norway’s Project Hessdalen active, but also to devote supplementary resources to it. [...] Here remains the possibility for Science to discover new phenomena, extraterrestrial or otherwise." (Acta Astronautica 68  2–15)
This is a remarkable incident: A reknowned magazine for aerospace matters is asking if phenomena such as the Hessdalen Lights can be explained by an extraterrestrial intelligence (arguments in the discussion about the extraterrestrial hypothesis). According to common understanding such kind of speculation is breaking a taboo: Things like UFOs are considered as a modern myth, which can not be scientifically investigated.
Questioning existing knowledge is considered one of the big achievements of modern thinking. Scholars such as Gallilei, Kepler, Darwin and Einstein have made the principle of doubt a cornerstone of scientific method.
Also regarding the Hessdalen Phenomenon we should consider explanations, questioning existing knowledge about the world. No scientist will ever rule out any possibility in advance, when looking at a certain phenomenon. We should rather have a critical look on proposed explanations: Speculations an extraterrestrial intelligence should be considered as critical as hypothesis about piezoelectric effects and radon decay. "I know that I know nothing" -
A common argument against the extraterrestrial hypothesis consists in a figure of thought called "Ockham´s razor". According to this principle each phenomenon should be explained by as few assumptions as possible. As the existence of extraterrestrial visitors can not be considered as affirmed, we should prefer to explain the phenomenon by proven assumptions.
However, the physicists Boris Smirnov and David Fryberger conclude that the phenomena observed in Hessdalen cannot be explained using today’s mainstream science and instead require the development of new approaches to physics . This being the case, then, it also bears asking whether introducing the possibility of an extraterrestrial intelligence might indeed be a more promising additional assumption than the development of a new physics.