Generation and Reduction

The reductionist paradigm bequeathed to us from the ancient Greek philosophers always had trouble with life. Aristotle found it necessary to invoke a dualistic explanation, dividing the world into body and soul, matter and an organising priciple. Iris Fry, in her book The Emergence of Life on Earth, devotes the first five chapters to the historical background of thought on the origin of life, and Aristotle's idea, suitably kneaded and pummeled, formed the foundation until nearly the beginning of the twentieth century. Actually, even today it's hard to take much exception to Aristotle, except that we now know that the organizing principle, or soul, is embodied in the information stored in material, the DNA.

Although early Greek atomists resisted making a distinction between living and nonliving, the difference is simply too marked to be ignored. The problem that now bedevils us, abiogenesis, or the development of life from non-living material, wasn't a problem for much of the intervening history, says Fry, because most believed in spontaneous generation. In those pre-microscopic days, insects, worms, and even amphibians and reptiles were thought to develop spontaneously in mud or decaying organic matter.

Once anatomists began to dissect insects and follow their lives in detail, spontaneous generation began to crumble, but it clung to the world of microscopic life for a lot longer. One interesting aspect was the attitude of organized religion: the church had adjusted its views from time to time, but was fundamentally cool with spontaneous generation. Atheists were also down with it, but as more detail was learned about the actual complexity of even microscopic life, it became harder to defend the notion of spontaneous generation of such complex designs.

The crucial showdown came with the experiments of Pasteur, showing that properly sterilized solutions would not give rise to life, but as soon as contact with unpurified air or dust took place, life exploded. Pasteur claimed that his experiments proved the necessity of divine intervention to produce life originally - putting the lie to what he called a "useless god", but he also had some contrary ideas as well.

His earlier work had been concerned with crystals and compounds that showed optical rotation, and he had shown that biologically produced tartaric acid produced optical rotation, while racemic acid with the identical chemical composition, produced through laboratory chemistry, did not. Ultimately he was able to crystallize racemic acid, separate the two kinds of crystals found, and show that they produced optical rotation in different senses. This led him to suspect that a chiral force or principle was a key to life - a brilliant piece of analysis, but a mainly blind alley as far as the origin of life.

Darwin and his theory of natural selection came next, but he realized that the problem of origin of life was beyond the knowledge of the day. The effect of Darwin's theory, though, was to confine the role of the otherwise "useless god" to the origination. In fact, significant further progress had to wait until the early part of the twentieth century.

I found these philosophical and historical bits an interesting introduction to the modern work - I hope Fry will do as good a job with it.