Saturday, February 27, 2010

Evolution & Christianity, Part I - What is Evolutionary Theory?

I. The Importance of Addressing Evolution

This morning I want to talk about the relationship between evolution and Christianity – a controversial topic, but one which needs to be addressed. Why is this an essential topic to address?

A. Evolution is a major cause of unbelief

First, evolution is perhaps the major intellectual cause of unbelief in North America today. That is, for people who either renounce or reject Christian theism, evolution is the most commonly cited reason. Specifically, students will often claim, “I was presented with the evidence for evolution, and saw that evolution is incompatible with Christianity. The evidence for evolution seems overwhelming; thus, I have to reject Christianity, as it seems based on faith rather than fact.”
A major purpose of Christian apologetics is providing struggling or doubting Christians with reasons to continue to believe – what I call closing the back door of the church. We must face the reality that there are probably hundreds of thousands of Christian students who are slowly being persuaded that evolution makes Christianity impossible.

B. Evolution is a major contemporary worldview

Second, as Christians, we need to understand the times that we live in, and the mindset of people in our world. Evolution is a, perhaps the, dominant cultural worldview in North America today. In order to understand how folks are thinking, we need to grasp the variations and implications of evolution.

II. The Importance of Defining and Understanding Evolution

Understanding evolution is easier said than done, partly because it is often undefined, poorly defined, or just defined differently by different people. Let’s take a look at the three major ways that people can and have defined (and understood) evolution.

A. Micro-Evolution (Adaptation)

In its simplest and least controversial definition, evolution is simply adaptation – the ability of a species to adapt to a changing environment in order to survive and thrive. Thus, for example, in famous studies of Galapagos finches, the average size and shape of beaks was observed to change in accordance with unusually dry or unusually wet climate cycles and the resultant change in food sources and abundance. Alternatively, we can see the increase in average human height and weight over the past two hundred years in response to improved medical care and availability of food.

This brand of evolution is called “micro-evolution,” although it should more naturally be designated simple adaptation. There is no question whatsoever that this type of evolutionary theory is perfectly compatible with orthodox Christianity.

B. Macro-Evolution (Darwinism)

The second common way of understanding and defining evolution is classical Darwinism, or ‘macro-evolution’. This begins with the observations and thesis in the first (adaptational) definition of evolution, but builds upon it. Darwinism, as classically expressed in Charles Darwin’s 1859 blockbuster The Origin of Species, extrapolates from variations within species, and posits variation between species. The adaptations that we see, for example in finch beaks, continue and compound over time, and eventually result in speciation – or alteration from one species into a new, distinct, species. Thus, for example, the Galapagos finches, whose beaks change in response to changes in the food supply, would speciate into a new variation of bird entirely if the changes in food supply became permanent.
The mechanism through which speciation occurs is random mutation and natural selection. Random mutation simply identifies random genetic mutations which result in offspring with slight differences from the parent. Natural selection indicates the reason that some random mutations are preserved in future generations while others are not. Simply put, Darwin’s theory was that some mutations were beneficial for the survival and success of an organism, and for that reason were preserved through reproduction. The offspring of the positive mutant also contain the mutation, and thus are better adapted to survive and thrive; they then pass along the mutated gene to their offspring, etc.

Over time, these gradual, cumulative changes accrue in offspring, and eventually result in a specimen which is distinct from the distant ancestor. Thus, for example, if we observed, say, 100 generations of Galapagos finches evolving within an altered (but stable) environment, the finches in that hundredth generation may well be so different from the first generation that they would be an entirely new species of finch.

Extrapolated over millions (or billions) of years, the accumulation of gradual changes within species are responsible for what we observe as the tree of life. Darwin traced the incredible variety and proliferation of biological life on earth back to a common ancestor, the original life-form on earth. Now, it is essential to note that Darwin’s common ancestor was a robust organism with the five senses which we are accustomed to enjoying. Most contemporary evolutionists insist that our common ancestor was not this robust organism posited by Darwin, but rather was a single-celled organism, with no sensory experience at all. In that sense, they are not Darwinists, but rather neo-Darwinists – Darwinists with a difference.

At any rate, this definition and understanding of evolution begins with the common ancestor, and argues that all life (including human beings) have descended from that common ancestor through a combination of random mutation and natural selection.

Is this understanding of evolution compatible with Christianity? This is a hotly-debated issue, and I don’t pretend to have the final answer - nonetheless, I will contribute my thoughts on the issue. There are a number of Christian thinkers who are known as “theistic evolutionists,” or “evolutionary creationists,” or any other number of terms that indicate that they embrace both biblical Christianity and macro-evolutionary theory. Theistic evolution, generally speaking, accepts the precepts of Darwin’s theory of evolution, and seeks to accommodate it within a theistic (i.e. Christian) worldview. Hence, they may say something like: “Evolution is the mechanism by which God went about a part of His Creative work.” For a theistic evolutionist such as Dennis Lamoureux (a professor at my alma mater, the University of Alberta), the general truth of evolutionary theory does not undermines or challenge his faith in the God of the Bible – rather, it enhances it. Dr. Lamoureux speaks of how evolution helps Him to understand more of the mind and the workings of God Almighty.

While theistic evolutionists understand Christianity and evolution to be compatible, the general tenor of evangelical conversation insists that there is absolutely no way to reconcile evolutionary theory with Christianity, and that theistic evolutionists are basically betraying their Lord and Savior (or, in a popular and effective phrase, ‘giving away the store’).

Speaking personally, I think this is incorrect. First off, there are theistic evolutionists who, in my estimation, hold a sincere, evangelical faith themselves – Richard Swinburne, Alister McGrath, Dennis Lamoureux. I may not agree with them on everything (particularly on the question of evolution), but I am unwilling to brand them heretics on account of their evolutionary views. I believe that evolution can potentially be reconciled with a biblical worldview. That is, I do not think it is necessarily a contradiction in terms for someone to be called a “Christian evolutionist”. I do think that this requires a major revision of the first plank of Darwinism – random mutation – as the driving process to evolutionary change; but theistic evolutionists generally make that revision, and speak of the process of natural selection being guided by the purpose and direction of an omniscient God (one exception seems to be Francis Collins, who I suspect is an open theist). [At this point, one could very legitimately question whether theistic evolutionists are evolutionists at all, since Darwinism holds to an undirectly, random process of mutation. Theistic evolutionists would simply respond by identifying natural selection as the key mechanism of Darwinism, and random mutation as an additional philosophical thesis piled on top.]

Let me give you two examples to hopefully illustrate what I am getting at here.

First, imagine being a sincere, Bible-believing Christian in Galileo’s days. You’ve been hearing that there’s this new guy who is proposing that the earth is not the center of the universe, but that rather the earth revolves around the sun. This is major news, because for centuries the dominant worldview has been geocentric. Now this crazy Italian is proposing a heliocentric model of the solar system. I am hopeful that, if I happened to be alive during Galileo’s days, I would have had the wisdom and discernment to see that heliocentrism did not contradict biblical Christianity. I probably would not have leapt up and defended Galileo’s model, proclaiming that it “must be true because it isn’t contradictory to our faith”; however, I hope that I would not have branded him a heretic for proposing a system which contravened general scientific thought at the time. And, of course, as things turned out, Galileo’s model turns out to be right, and everyone now realizes that it is not in the least bit threatening to the Christian faith.

Second, imagine, just for the sake of argument, that there does exist intelligent life somewhere on a distant planet in the far corner of the universe. If you’re like me, this requires you to suspend disbelief, but go with it. Does the existence of life elsewhere in the universe contradict biblical Christianity? I don’t think there’s any way that we can conclude that it does. It would certainly require us to refine some of the ways that we think about the universe, but there is nothing in the tenets of our faith which dogmatically require us to believe that there cannot be life out there somewhere.

With both of these issues – heliocentrism and extraterrestrial life – the main question is not whether they contradict biblical Christianity, but rather whether or not they are true. With heliocentrism, we understand that it is a true theory which does not contradict our faith. With extraterrestrial life, I understand (and I hope you do too) that it is a false theory which nonetheless, if true, would not contradict our faith.

This is the mindset with which I would argue we need to approach the issue of evolutionary theory. I propose that it is not inherently contradictory to our Christian faith. But the more important question then becomes: is it true? If it is true, then we better do the hard work and reconcile it to our worldview; if not (and, as will become clear, I highly suspect that evolution is not true), then we should reject it as being false. However, before we launch into a critical examination of Darwinism, let’s look at the third understanding or definition of Darwinism current in society today.

C. Evolution as a Worldview

This understanding of evolution includes both of the above definitions – adaptation and descent from a common ancestor, but goes further yet, and develops evolutionary theory into an all-encompassing worldview.

First, worldview evolution includes a professed explanation for the origin of life on earth. Remember, classical Darwinism begins with life (robust life at that) and argues common descent from that point. Worldview evolution seeks also to explain how life came to be. The argument, put simply, is that life evolved through the same random processes combined with natural selection that later resulted in the proliferation of life on earth. The early earth, it is held, contained some kind of prebiotic soup (the contents of which are hotly debated); out of that interacting prebiotic soup, plus the external application of energy (through lightning, etc.), enzymes formed, combined into proteins, and eventually, given enough time, resulted in the formation of the first simple life form – a single-celled organism that we’ll call Adam. Adam managed to reproduce himself, and from this earliest simple life-form, again given sufficient time, all of life evolved.

Second, worldview evolution includes an explanation of the universe itself. That is, the grand narrative of evolution explains how the universe came to be, and why it is structured the way that it is. Most often, worldview evolution invokes the majesty of multiverse theory as the explanatory mechanism for the universe.
Third, worldview evolution includes an explanation of sociality – that is, human ethics and religion. According to the grand evolutionary story, human morality and spirituality have evolved over time. Ethics and religion are, or at least were at one time, facets of existence which facilitated human survival and flourishing. I will devote future blogs to these topics of conversation, so I won’t spend more time on them right now. What is essential to note is simply that the worldview version of evolution seeks to provide a natural (and naturalistic) explanation for human morality and spirituality.

Is this version of evolution compatible with Christianity? While it is clear that the first definition of evolution (micro-evolution or adaptation) is perfectly compatible with Christianity; and the second definition of evolution (macro-evolution or classical Darwinism, descent from a common ancestor) is potentially compatible with Christianity; this third definition of evolution is quite clearly not compatible with Christianity. The main Darwinian mechanism of random mutation and natural selection has already sought to remove the concept of design or teleology from an explanation of biological life. The further worldview understanding that evolution is sufficient to explain the origin of life itself and the existence and nature of human morality and religion, has entirely removed the possibility of the divine from the scope of reality. God is not required (or permitted?) as the originator of biological life. God is not required (or permitted?) as the explanation for the existence and fine-tuning of the universe. God is not required (or permitted?) as the explanation for the unquenchable religious spirit of humanity. God is not required (or permitted?) as the explanation for the undeniability of ethical absolutes. God has been irrevocably removed from the picture of life, the universe, and everything.
When evolution becomes an all-encompassing worldview in this way, theism has been explicitly rejected and rendered impossible. Evolution is no longer a part of the story – evolution is the whole story.

D. Which Version of Evolution is Predominant?

In terms of what is presented and evidentially defended in academia and society, the second version of evolution is predominant. When college students come face-to-face with evolutionary theory, it is the idea of common descent that first confronts them. However, underneath the presented understanding of evolution usually lies a worldview which has been affected and eventually enveloped by naturalistic evolution – the third definition of evolution. The scientific evidence, so far as it goes, supports only the second picture of evolution. The extrapolation to the third definition requires philosophical assumptions and the imposition of a naturalistic worldview.

What this discussion has hopefully uncovered is the necessity of identifying exactly what someone means when they say, “I can’t believe in Christianity – I believe in evolution.” What kind of evolution do they believe in? On what basis do they believe in the evolution that they have embraced? [Incidentally, I think this is also true when someone around us says, “I am a Christian.” We ought to ask, “Well, what kind of a Christian are you? Biblical? Cultural? Revolutionary? Orthodox? And on what basis do you embrace Christianity? “] We should not simply assume that we know what someone means when they say they accept evolution as the explanation for life. Ask them. Find out exactly what they mean. Then you can address them in terms of what they actually believe, rather than on the basis of what you presume they believe (based on your own understanding of cultural evolution).

In my next post, I will assess the value of evolutionary theory, and show the reasons why I think it is probably untrue (in both the second and third variations discussed above).