[dekhn]

theoretically possible but there is no evidence to suggest this. Weighing the various hypotheses, most people would suggest the "simpler" (fewer wipeout/arise events) hypothesis, given the assumption that life arising is considered very rare.

[JoeAltmaier]

Because the earth remade itself several times. Any previous life would have surely been erased. The assertion was that life arose just once. That's hard to prove.