> Conclusion 2: the great filter is likely in the past
Is there an article to go with these slides? I'm somewhat competent with probability theory and I found it hard to follow with all the unmarked graphs and unexplained parameters.
If on the other hand the early terms are much lower than expected, as this PDF is discussing, then the sum total of them could be considered the "Great Filter" and we could be past it. It's fine to just lump them together from our point of view, since at the moment we don't have the data to figure out which gate is "really" the determinative one.
Wandering down my own thoughts here: The Copernican Principle, or perhaps better termed in modern parlance the Copernican Heuristic, that we are nothing particularly special, has had a good run. But it is just a heuristic, and one whose adherence has arguably been driven more by a science v. religion feud than logic or data, and whose underlying logic in the past 50ish years has metastasized into "Some religious people I don't like think Man is unique, they're wrong about everything, therefore Man is not unique in any way." But lately the Copernican Heuristic has been showing a lot of strain. Our solar system may not be unique, but it is increasingly looking like it may indeed be unusual, for instance. The Rare Earth arguments have never gone away and I think a lot of the dismissal of that idea has also come from "Religious people like the idea of the Rare Earth and some of them are arguing for it, religious people are wrong about everything, therefore Earth is not rare." [1], because scientifically they look as good as anything else on the subject (namely "those arguments seem to fit our lack of data as well as anything else", which is a pretty weak endorsement). And per the PDF under discussion, a lot of the universe really starts to make more sense when you start to seriously consider the possibility that, yes, we may in fact be very unusual, if not perhaps truly unique.
[1]: Those are not the only arguments here, nor are they the best; I'm just saying that it is my subjective sense that the debate over the past few decades has often been very skewed by the underlying presence of this argument, even when not necessarily spoken. It is my perception that this debate has often been had under unspoken ground rules where all the discussion must occur in such a way as to ensure that the religious people are unable to point to anything as evidence for their side. It... doesn't make for the best conditions to do science under.
The number of civilizations, N, is assumed to be equal to the mathematical product of
- the average rate of star formation, R∗, in our galaxy,
- the fraction of formed stars, *fp*, that have planets,
- for stars that have planets, the average number of planets *ne* that can potentially support life,
- the fraction of those planets, *fl*, that actually develop life,
- the fraction of planets bearing life on which intelligent, civilized life, *fi*, has developed,
- the fraction of these civilizations that have developed communications, *fc*, i.e., technologies that release detectable signs into space, and
- the length of time, *L*, over which such civilizations release detectable signals.
> Anders Sandberg, Stuart Armstrong, and their co-author Milan Cirkovic published a paper outlining a potential strategy for advanced civilizations to postpone computation until the universe is much colder, and thereby producing up to a 10^30 multiplier of achievable computation. This might explain the Fermi paradox, although a future paper from FHI suggests there may be no paradox to explain.