Roger Oliver and Jef Pirie on the prospect of finding other life in the galaxyProfessor Jim Al-Khalili (Opinion, 27 June) says: “There are some who argue that life on Earth appeared pretty quickly after the right conditions emerged almost 4bn years ago, which was when our planet had cooled sufficiently for liquid water to exist. Doesn’t that mean it could easily appear elsewhere too? Actually, no. A statistical sample of one tells us nothing”.
Well, actually, yes. If we had evolved on a planet circling a dying star and observed that although environment conditions for life on Earth had existed for many billions of years before finally getting started, then we might reasonably conclude that the emergence of life was a bit, well, tricky. Since we actually observe that life got started “pretty quickly” then we ought to conclude that it’s not particularly improbable. True, we only have one datum point, but it’s not nothing.