The flaw in the argument lies in the inference that, because life has arisen here, it can’t be too terribly improbable. You will notice that this inference contains the built-in assumption that whatever went on on Earth is likely to have gone on elsewhere in the universe, and this begs the whole question. In other words, that kind of statistical argument, that there must be life elsewhere in the universe because there is life here, builds in, as an assumption, what it is setting out to prove. This doesn’t mean that the conclusion that life exists all around the universe is necessarily wrong.
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