Abstract

The origin of life on Earth is one of the great unsolved mysteries of science. Although no complete account of life’s beginnings is available and although no life forms that emerged independently on other planets have been discovered, most origin-of-life-researchers and astrobiologists dismiss a chance scenario out of hand. I argue that this is a mistake for at least two reasons. First, given a sufficiently big and adequately variegated cosmos any finite chance of life emerging on Earth-like planets will virtually guarantee the formation of life somewhere. An observational selection effect could then explain why the cosmic neighbourhood we find ourselves in is a very special place (Vast Cosmos Argument). Second, as White (2007) has pointed out, there seems to be no conceivable a priori reason to suppose that processes by which complex molecules arise are more likely to be unintentionally biased towards self-replicating, life-producing molecules than to other types of molecules (Indifferent Nature Argument). Objections to both arguments are discussed and rejected.