In his latest blog, Robin Hanson writes
There have been over 100K UFO sightings reported worldwide since 1940. Roughly 5% or so are “strong” events, which seem rather hard to explain due to either many witnesses, especially reliable witnesses, physical evidence, or other factors.
Yet, I am not aware of a single UFO encounter that can't be explained by one of:
- Unreliable eyewitnesses
- Things that go away when we get better cameras
Importantly, Hanson's post did not include a link to the "Wikipedia of UFO encounters" listing all 100k UFO sightings and which 5000 he considered most credible.
Where is that Wikipedia?
We don't see any evidence for what I would call stellavore civilizations, but that was always a strange model of the future anyway. Regardless it just seems incorrect to have a stronger prior on the future of technological civilization than the copernican prior on the uniqueness of earth. In other words the prior that aliens never developed anywhere in the galaxy before us starts as something like (1−X)N, where X is the probability that a specific alien star developed civilization and is constrained by the copernican/anthropic considerations and can't be a tiny probability, but N is a very large number in the billions.
We know the value of N more or less, and via copernican/anthropic arguments we have some confidence X can not be too small, which leads to more confidence that aliens exist than justified confidence that we know the shape of future tech civilizations. So from that we can rule out stellavores.
Stellavores are literally stupid anyway as they can't utilize exotic reversible/quantum computing at scale - exploiting the latter requires moving out into the cold dark void. Any advanced tech civ will need to achieve near zero temp, and doing that at scale naturally results in being difficult to detect.