Science and superstition
RADHAKRISHNA
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Natural selection succeeds where chance and design both fail
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P.A. WAHID'S article (Open Page, December 31) refers approvingly to the theory of ID or intelligent design, as an alternative to Darwinian evolution. ID is a politically correct term for creationism, which invokes the action of supernatural forces or beings, creating material objects including life forms.
The chance production of complex biological structures such as eyes or wings, so perfectly adapted for specific purposes, is, of course, highly improbable.
The argument for ID or creation states that since chance is excluded, the intervention of a supernatural Designer is automatically implied. This theory immediately runs into the contradiction that It (He?) has to be so much more complex than the object designed, that His origin, too, becomes improbable.
An alternative
Darwinism has provided a scientific alternative mechanism, by teaching that biological evolution proceeds, using gradual ramps rather than attempting to scale the sheer cliff of apparently insurmountable complexity in one wild leap of creation. Evolution proceeds by incremental changes, by an infinity of intermediate forms, each only a little more complex than its predecessor and a little more adapted to the environment, maximising a utility function.
The development of complex organs like the eye, from the earliest beginnings as groups of light-sensitive cells in primitive worms to the fully fashioned organs of mammals and human beings, is well-known. Computer simulations can home in, unerringly, on the essential features of mammalian eyesight, from very few assumptions. Natural selection succeeds where chance and design both fail. It is a cumulative process, producing a finished adapted structure.
No cases of irreducible complexity, or complex organs, which cannot be formed by the accumulation of numerous small, successive and slight modifications, have ever been found.
Our understanding is also buttressed by studies on the geographical modifications of related species, such as red and brown squirrels. Long human experience of animal breeding has produced innumerable varieties of dogs from the ancestor wolf, or exotic gold and yellow fantail fish from dark, unprepossessing carp.
Molecular genetics and, finally, mathematical models of increasing complexity confirm the features of the evolutionary algorithm. These models follow a search path, according to its rules — replication, selection, mutation, sex, and random drifts, producing complex fits, adapted to the environmental conditions specified.
Fossil evidence in chronologically layered rock strata confirms the evolution of new species with successive modifications. If a single fossil turned up in the wrong geological stratum, the entire edifice would be called into question, as, for instance, if fossil rabbits had been discovered in Precambrian rock. No such cases have ever been discovered, and the internal consistency of this narrative is reassuring.
Creationists often seek for gaps in our present understanding of science, to assert that God is, by default, a valid alternative. Science proceeds with the conviction that further investigation will diminish these gaps, while the creationist, typically, throws up his hands in an intellectual gesture of abandonment, invoking divine intervention.
It requires considerable chutzpah to dispute the tenets of Darwinian evolution. The extensive work of Richard Dawkins on genes and on memes, denoting a second replicator of cultural units, has recently opened pathways to a new understanding of the algorithm.
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