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What Evolution means to you?

The following post is about the importance of defining the terms precisely so that conversations more fruitful. Specifically the word “Evolution” in conversations about science and religion.

Evolution is a tricky thing to talk about. I generally don’t make a practice out of it. There are other more important things to discuss, like the existence of God, the deity of Christ and the historicity of his bodily resurrection from the dead. If I were to talk about evolution, then I insist on defining the term, so that we know exactly what is being discussed and the conversation can be directed without it sliding back and forth.

Part of the role of philosophy is conceptual clarification of terms, and for this the work of the eminent evolutionary biologist Francisco Ayala, and Christ follower, is useful. He says that evolution is an accordion term that can be contracted and expanded depending on the context. As such he distinguishes “evolution” as being at least three different things

The first is one that all agree on – not even the strictest creationist would deny it. It is that present day organisms are descended from organisms that lived earlier with modifications. This is the level at the bottom of the following chart, and is coloured green because it so uncontroversial. Lab technicians, for instance, cultivate bacteria and analyse the modifications in order to develop more disease resistant drugs.

The second, coloured orange and in the middle, is where some dispute enters onto the scene. It is the explanatory mechanisms behind evolution, such as genetic mutation and natural selection. These are the various factors that bring about said changes in category one. Here intelligent design theorists would contend that purely natural forces working are insufficient as an explanation, but require the input of an intelligence. But intelligent design theorists are not alone in their dispute about these forces. A growing number of scientists are looking in other areas for explaining evolutionary change, such as investigating the role viruses play when inserting their own DNA into the genetic code of the animals they infect.

The third is the evolutionary tree of life that seeks to show all of the branches going back to some common ancestor in the distant past. This is the thesis of common descent. It represents an extreme extrapolation of the observational data we have. Consider not only all the changes necessary to go from one type of animal to another, but the huge difference between the animal kingdom and the plant kingdom. And these are not even that far apart on the evolutionary tree of life. This level is therefore the most controversial. Though some Christians, like Intelligent Design advocate Michael Behe, find no problem with believing human beings share common ancestors with the great apes and all life has a common ancestor, others do not. Many secular scientists find this troubling as well, and therefore propose theories such as multiple origins of life, and panspermia – or seeding the world with life from somewhere off planet, i.e. a comet or alien visitor.

Francisco Ayala says candidly is that while evolution in the first sense is a fact, the other two are matters of tremendous dispute, and he says there’s a whole lot that we do not know about these issues and are still matters of ongoing research.

All this is to explain one term. What happens to the discussion when other terms are brought up? What about Darwinism? Is this simply the “Neo-Darwinian synthesis” of natural selection working on time and chance mutation, or does it also involve a philosophy that excludes intelligent agency as a precondition of appropriate science. What about Intelligent Design? Opponents insist is Creation Science in disguise, and proponents insist it is completely different from the fact that it is a thesis based upon the commonplace, sensible inference that codes require some sort of coder for their origin. This is all just to say that conversations on evolution and Intelligent Design are destined to failure if we can’t agree upon, and stick to, definitions of foundational terms.

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