Ongoing debates: the origin of life

It is perhaps remarkable that fifty years after Watson and Crick detailed the structure of DNA and Stanley Miller performed the first bold experiments aimed at producing self-replication biochemistry, there is little consensus on how life started. This is sometimes referred to as the problem of ‘abiogenesis.’ Darwin’s advocates often present natural selection as a complete and satisfying account of biology. Dawkins goes so far as to say it “solves the mystery of our existence.”If we consider its potential application beyond biology to social contexts through sociobiology it could theoretically explain a great deal more than our existence. However, the power of natural selection only comes into the picture once we have the twin components of replication and inheritance with variation. But do these twin features arise inevitably? If not, their origin will need be to be explained.

There is still optimism that the problem will be solved, but at the moment it is hard to predict how much will be attributed to chance. As with natural selection, until we have some confidence as to the probabilities involved it is possible to draw a wide range of conclusions. On the other hand, Manfred Eigen considered our knowledge to be sufficiently detailed to declare life “inevitable.”Biochemist George Wald shares this view, also concluding that “the universe breeds life inevitably.”

In recent years, Miller’s experiments have been refined and greatly enhanced, but as Ruse puts it: “at the moment the hand of human design and intention hangs over everything...” Stanley Miller himself has become cautious: “the problem of the origin of life,” he says, “has turned out to be much more difficult than I, and other people, envisioned.”The difficulties have led no less an authority than James Watson to the conclusion that it the origins of life should be considered “almost a miracle.”

Despite the challenges, abiogenesis research has made laudable progress on several fronts. Two facts have emerged: there are plausible scenarios for how several amino acids were produced, and there is evidence that complex life developed early on. For example there is evidence that carbon from 3.8 billion years ago passed through photosynthesis indicating the presence of complex plant-like organisms. This means that life must have arisen on Earth almost soon as the Earth could physically support it. This fact suggests three possibilities: self-replicating molecules are likely to form, life on Earth is due to incredible luck, or life originated somewhere else (where the improbabilities are lessened through different physical circumstances or the availability of time). Francis Crick and Fred Hoyle advocated this third theory which they referred to as ‘Panspermia.’

The lack of a detailed account of the origin of life means that it is too early to say that evolution provides an answer to the mystery of our existence.

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