More on the implications of Fermi’s paradox

March 28, 2010

I wrote the post below a while ago – not long after my original Fermi’s paradox post linked to. Somewhat startled and uncertain about the conclusions drawn at the second part of the post, I filed it away. Looking at it again, the reasoning seems plausible, and no obvious counterarguments come to mind.

This post aims at pursuing somewhat further a line of thought explicated earlier. As before, the jumping point is the realization that among all [near] space-faring civilizations (SFCs) to ever develop in the universe (in the past or in the future) the human SFC is a-priori unlikely to be an a-typically early one. Thus, either (1) there are, and ever will be, very few SFCs in the universe (and of those, all those that are earlier than humans either met with misfortune or have shown self-restraint in polluting the universe) – this is the “rarity” option, or (2) there are many of them, but they – in some coordinated way – are making sure we are unable to observe them – this is the “protected wilderness” option.

The first possibility – rarity – which has some proponents – can be developed further: sub-possibility (1a) is that the universe is naturally inhospitable to SFCs – in the lifetime of the universe there are likely not to be many SFCs. Sub-possibility (1b) is that it is the first SFC that achieves cosmic scale (presumably the human one) manages, deliberately or non-deliberately, to suppress all later budding SFCs.

Under both those options, the universe as we know it – the pristine, unkept place which gave birth to the human SFC – cannot exist for much longer (i.e., more than, say, a few hundred times its current age), since if it did, some later SFCs would develop, some of which, presumably, would have cosmic-scale impact.

The same type of appeal to non-extremity, however, can also be used to argue that we, i.e., people living now, are not particularly early specimens of the members of the human SFC. Thus, the total number of human beings being part of the human SFC is unlikely to be much larger than a few hundred times its current and past membership (which is about 10 billion people). This seems to rule out the possibility of a large scale colonization of space by humans, but does not rule out over-running of the galaxy (or universe) by von Neumann probes originated by a human-made seed, which could be a cause for the non-development of other civilizations.


One Response to “More on the implications of Fermi’s paradox”

  1. Yoram Gat Says:

    It turns out that the argument I proposed in the last paragraph is a version what has been named “The Doomsday argument”.

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