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Arguing About Extraterrestrial Intelligence

Cowie, Christopher



Avi Loeb has defended the hypothesis that the interstellar object, ‘Oumuamua, detected in 2017, is in fact an extraterrestrial artefact. His hypothesis has been widely rejected by the scientific community. On examination however it is not clear why. The puzzle is at the level of argument structure. The scientific community's responses to Loeb's hypothesis appear to point to explanations of ‘Oumuamua's properties that are mere possibilities. Yet this is something that Loeb does not contest. I appeal to broadly philosophical considerations to understand and bolster the response to Loeb. These considerations concern the structure of his argument, the role of prior confidences within it, and the presence of ‘unconceived alternative’ explanations. I then generalise. ‘Oumuamua will surely not be the last object that does not admit of straightforward natural explanation and that is claimed to be evidence of an extraterrestrial artefact. I use the preceding discussion of Loeb's argument and the scientific community's response to make some general remarks for future debate about similar cases.


Cowie, C. (2023). Arguing About Extraterrestrial Intelligence. Philosophical Quarterly, 73(1), 64-83.

Journal Article Type Article
Acceptance Date Feb 17, 2022
Online Publication Date Mar 26, 2022
Publication Date 2023-01
Deposit Date Feb 28, 2022
Publicly Available Date Mar 27, 2024
Journal Philosophical Quarterly
Print ISSN 0031-8094
Electronic ISSN 1467-9213
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 73
Issue 1
Pages 64-83


This file is under embargo until Mar 27, 2024 due to copyright restrictions.

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