Bostrum offers an alternative way of looking at the evidence. We can't tell anything about the prevalence of extraterrestrial civilisations merely by looking at our own, but by expanding our search we can start to draw conclusions based on what we find. So far we have found nothing - but this may be simply because we haven't looked far enough.

Once we gain the technology to look deeper into the universe in a search for life and civilisations, then we can start drawing some tentative conclusions. If we continue to find no evidence, that would have certain implications, which we have explored in a number of threads on this forum; and of course if we do find evidence of life or civilisations,that would open a whole new field of inquiry.

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