army1987 comments on The Octopus, the Dolphin and Us: a Great Filter tale - Less Wrong

48 Post author: Stuart_Armstrong 03 September 2014 09:37PM

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Comment author: [deleted] 12 September 2014 08:01:27AM 3 points [-]

Meaning that as a layman, I don't see how we'd distinguish between a past where Earth was hit by a "lethal" GRB 2 billion years ago (when there were just eukaryotes, procaryotes and cyanobacteria), and one were it wasn't.

Indeed, according to Wikipedia at least, we don't know whether the Ordovician–Silurian extinction event was caused by a GRB or not.