04/08/2011 01:33 pm ET Updated Jun 08, 2011

Contingency or Convergence?

Aristotle introduced the principle of Final Cause in which objects move in the direction toward their ultimate goal. For example, of the four elements, fire and air move up while water and earth move down because each is heading toward its natural resting place.

Today many theologians and some scientists say they see evidence exists for a teleological principle built into nature, beyond known physics, that causes matter to become increasingly complex with time. The eminent physicist Freeman Dyson has said:

Before the intricate ordered patterns of life, with trees and butterflies and birds and humans, grew to cover our planet, the earth's surface was a boring unstructured landscape of rock and sand. And before the grand ordered structures of galaxies and stars existed, the universe was a rather uniform and disordered collection of atoms. What we see . . . is the universe growing visibly more ordered and more lively as it grows older.

The late Stephen Jay Gould had made the argument that evolution does not show signs of progress, that it was arrogance for humans to place themselves at the top of the evolutionary ladder. However, Christian apologist Dinesh D'Souza assures us that this is no longer "conventional wisdom" in biology and that some prominent biologists, notably the Nobel laureate Christian de Duve and Simon Conway Morris, the leading expert on the fossils of the Burgess Shale, have argued that "all this talk about randomness and contingency is overrated." They claim to see evidence for a plan in evolution.

In his 2003 book Life's Solution: Inevitable Humans in a Lonely Universe, Conway Morris assembled a collection of examples of what is called convergent evolution. As he explains it, from very different starting points organisms "navigate" to the same biological solution. In the most commonly discussed example, the same one used by William Paley, the eye evolved on multiple occasions along separate evolutionary lines with the same goal in mind--sight. Conway Morris claims to see the same convergence everywhere, from molecules to social systems and insists that it is very unlikely to have resulted from conventional Darwinian evolutionary processes.

According to Conway Morris, evolution has reached its limit. In a 2009 letter to the Manchester Guardian he betrays a religious motive that may color his scientific conclusions:

When physicists speak of not only a strange universe, but one even stranger than we can possibly imagine, they articulate a sense of unfinished business that most neo-Darwinians don't even want to think about. Of course our brains are a product of evolution, but does anybody seriously believe consciousness itself is material? Well, yes, some argue just as much, but their explanations seem to have made no headway. We are indeed dealing with unfinished business. God's funeral? I don't think so. Please join me beside the coffin marked Atheism. I fear, however, there will be very few mourners.

While there is no doubt that some tendency toward convergence is present in evolution, its mere existence does not prove it cannot be a simple consequence of natural selection. Let us consider the evolution of the eye. The fact that different evolutionary paths lead to the same basic mechanism for sight can be trivially understood without the need for some guiding force. Just apply a little physics. Vision is obviously so important to an animal that strong selective pressures are naturally going to point it in that evolutionary direction. Light is made up of photons and there is only one way that photons can be detected: by knocking electrons in atoms either to a higher energy level or out of the atom altogether where they generate an electrical signal that can be transmitted to the brain. It follows that all evolutionary paths toward sight will have to converge at that point. However, beyond this basic physics there is little convergence evident in detail, with the vision problem solved by evolution in at least ten different ways.

D'Souza is being grossly misleading when he says Conway's view is somehow the new conventional wisdom in biology. The majority of biologists still adhere to basic Darwinism, in which life evolved by a process of randomness and natural selection. In his 2009 book Why Evolution is True, biologist Jerry Coyne notes that convergent evolution is a well-known process that is fully understood by conventional evolution. He says it "demonstrates three parts of evolutionary theory working together: common ancestry, speciation, and natural selection."

Coyne comments on the article by Conway Morris in the Manchester Guardian that I quoted above:

Conway Morris is way, way peeved at atheists. He mentions them several times in his piece. He thinks he has vanquished them with his "unanswerable" evolutionary arguments. But he has not. He is simply proposing a "God of the gaps" argument, and here the gap is our mind. It's Alfred Russel Wallace [who discovered natural selection simultaneously with Darwin, but became increasingly mystical] recycled. He is wrong: neither will atheism die, or even flinch a bit, and we will, I predict some day understand, as Darwin believed, that the human mind is simply a product of the blind and materialistic product of natural selection.

P.Z. Meyers, Professor of Biology at the University of Minnesota and the award-winning creator of one of the top science blogs on the Internet, Pharyngula, concurs. He calls Conway Morris a "theistic evolutionist who considers the entirely natural processes of evolution to be God's way of creating life."

Purpose remains today a major area of conflict between religion and science. Religion still insists that the universe has a purpose, with humanity at its focus. However no scientific evidence supports this yearning. The world looks exactly like it should look if it is not a part of any divine plan.