Finding a second, independent origin of life would change what humanity knows about biology. It would show that the transition from non-living chemistry to living systems happened more than once. Mars would become evidence that Earth was not the sole example, rather than simply a place that once had suitable environments.
Robin Hanson’s Great Filter argument asks an uncomfortable follow-up: if the beginning is relatively easy, which later transitions explain the absence of conspicuous extraterrestrial civilisations?
A discovery of microbes would not establish a catastrophe in our future. A difficult step after microbes could still lie far back in humanity’s past. The headline’s darker possibility depends on the Great Filter framework and its assumptions about evolution, expansion and what we should be able to observe. It is not an established consequence of discovering life.
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