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Sunday, 28 October 2007

What Does Evolution Mean? A Framework for Christians

Much of the confusion in the evolution debate lies in the meaning of the word “evolution”. Since it can have several different meanings, and even the scientific definition of evolution can include several distinct components, it is not surprising that many confusing and confused arguments are articulated. Certainly the conversation is very difficult when conversation partners discussing evolution do not share the same definition, conflate several of the definitions, or elevate one component of evolution to be descriptive of the whole.

Dr. Allan Harvey has provided a simple overview of the various meanings of evolution. Harvey, a fellow ASA member, recently taught a 6-part course on “Science and Nature in Christian perspective” at his conservative Presbyterian church in Boulder Colorado, and the 5th essay in the series is on evolution. (Note: The entire course looks outstanding. It is presented in clear non-technical terms, and Harvey includes wise counsel on how Christians who accept the integrity of scripture should approach science. For anyone beginning this journey, I highly recommend reading through the entire series)

Harvey provides a framework that includes 6 meanings for the word evolution, and remarks on both the scientific certainty and compatibility with the Christian faith for each definition. These six meanings are:

E1. Change over time
E2. Common ancestry
E3. Evolutionary mechanisms (genetic variation, natural selection).
E4. The ability for these Evolutionary mechanisms to account (physically) for common descent.
E5. Origin of life (chemical evolution)
E6. Evolutionism

I have grouped these meanings into three categories: those meanings for which the scientific evidence is overwhelming and thus enjoy an extremely high degree of certainty (E1, E2, and E3), those definitions that are less certain based on the scientific evidence (E4 and E5), and those definitions whose conclusions are based on metaphysical assumptions rather than the scientific evidence(E6).

Evolution Meanings Group#1: Extremely high degree of scientific certainty

Harvey’s first three meanings for evolution (E1 – E3) are all extremely well supported by the scientific evidence. There is also, in Harvey’s view, no incompatibility between these meanings and the Christian Faith.

E-1) Change over time. This is the most basic meaning of the English word “evolution,” simply meaning that something changes with the passage of time. For example, we might talk about the evolution of popular music, or the evolution of stars. With regard to living things, this simply says that things are different than they were in the past (there used to be dinosaurs; now there aren’t). Almost nobody denies this meaning.
The only opposition to E1 is in the time available for changes to occur. Young Earth Creationists (YEC) would disagree with the scientific consensus of cosmological evolution (formation of the cosmos eg. stars) because of the billions of years required for this process.

E-2) Common ancestry. This is central to what scientists usually mean by “evolution.” Common ancestry (or common descent) means that life has branched out, so dogs and wolves are distant cousins, dogs and cats are more distant cousins, and if you go back far enough dogs and fish, or dogs and trees, had a common ancestor. You can put humans in the family tree as well – related to chimpanzees, more distant from other mammals, and so forth.
As I’ve commented earlier here, a shared ancestry with non-human life does not contradict the biblical claim of humanity’s creation in the image of God. As well, as Harvey points out in his 3rd essay, and as I’ve commented here, common descent does not compromise the integrity of scripture. In fact, many of the leaders in the Intelligent Design (ID) movement (eg. Michael Behe, author of The Edge of Evolution) also support common descent, even though ID is often described as anti-evolution.

E-3) Evolutionary mechanisms (genetic variation, natural selection). This refers to specific natural mechanisms (first proposed by Darwin, although in a primitive way because genetics was not yet understood) that cause species to change. Genetic variation is the fact that (due to mixing of parental genes and to mutations) children have different genes and different traits. Natural selection refers to the fact that the traits will make some children more likely to survive and pass their genes on to future generations.
Note that in recent years even YEC organizations have started backing away from their opposition to the mechanism of natural selection (see here and here). They have also admitted that natural selection can lead to new species, and that “in fact, rapid speciation is an important part of the creation model”.

Evolution Meanings Group#2: Less Scientific Certainty

Harvey’s 4th and 5th meanings of evolution enjoy less scientific certainty (in fact, there is very little current evidence for E5). These definitions have historically experienced aggressive opposition from Christians (certainly more than E1-E3), but Harvey does not believe this needs to be the case.

E-4) Mechanisms (E-3) account (physically) for common descent. This is typically what scientists mean by “the theory of evolution.” We know these mechanisms produce changes in species, but do they account for all the evolution (in the E-2 sense) that has happened through the history of life on Earth? Most biologists, including most Christians working in these areas, would say “yes,” but it is certainly not as 100% established as the previous meanings.

I believe E4 is the meaning that sharply divides Christians who identify themselves as Theistic Evolutionists (TE) or Evolutionary Creationists (EC) from those who are anti-evolutionists, particularly those that are supporters of ID. Harvey’s 4th essay called “Natural Theology or a Theology of Nature” explains briefly why E4 should not really cause any conflict for Christians.

E-5) Origin of life (chemical evolution). The theory of evolution is only an explanation for the development of life from other life. How life began in the first place is a different question, but people have proposed somewhat similar theories (the technical term is ambiogenesis) of how that happened. That is an area where there is much room for doubt; some people see it as an insurmountable problem, while others think science is coming closer to good explanations.
E5 is the meaning that really sparks derision among anti-evolutionists. And the lack of evidence for E5 is often used to discount the validity of E2 through E4. It is still an open question whether a “natural” origin of life theory that is supported by the scientific evidence is 3 years away, 30 years away, 300 years away, or is practically impossible. The important point is that Christians need not oppose E5 for the same reasons that E4 need not be opposed.

Evolution Meanings Group#3: Definitions based on metaphysical assumptions

Harvey’s final meaning for evolution (E6) is unrelated to science.

E-6) Evolutionism. I use that term to refer to a meaning that is not science at all, but rather an ideology that sometimes masquerades as science. This starts with the philosophical position that natural explanations exclude God (the “God of the Gaps” error discussed in Chapter 4). Since science has produced these natural explanations for life, those with this ideology claim to have pushed God out of the picture. Of course these metaphysical conclusions are not science in any way – those who advocate this meaning are simply pushing atheistic philosophy, and it is wrong to try to claim it is a result of science.

This meaning for evolution is obviously not something that can ever be accepted by a Christian. But this is the meaning that both Christian anti-evolutionists and “evangelistic anti-theist” atheists push to the forefront. They conflate evolution meanings E2 through E5 with E6, and thus state that TEs and ECs are supporting atheism, materialism, or moral relativism (anti-evolutionist claims) or are deluded and cowardly for not following the scientific evidence to its logical conclusion (anti-theist claim).


I really like how Harvey categorizes the various definitions of evolution. They are helpful both for Christians trying to understand evolution, and for those of us that are frequently engaged in the evolution / faith dialogue. I am planning to use these definitions in my own conversations. Hopefully this will allow all of us to hone in on the salient issues more quickly, and avoid talking past each other. Ok, maybe that's overly optimist, but it can't hurt to try.


Gordon J. Glover said...

Another great post Steve!

Along these lines, I just completed part 1 of 3 part video "infomercial" called, "What's So Great About Evolution?"

Parts 2 and 3 are coming soon. I am also planing to post these on YouTube so they can receive a wider viewing than my other more lenghthy series, "Does Science Contradict the Bible?". Your readers might enjoy these.



Martin LaBar said...

Good job!

You may be interested in this web page, where I attempt to classify the meanings of "evolution," somewhat differently than this good job of it.
It seems clear that, although it doesn't really fit into the scheme you posted, the real sticking point for many Christians is the origin of humans.

Martin LaBar said...

Sorry, sort of, for commenting twice, but anyway . . .

It's probably important to distinguish between the proposed or actual mechanisms of evolution (such as mutation and natural selection) and the proposed or actual results of evolutionary processes (such as new phyla from old).

I haven't always made this distinction myself, and I should have.

Thanks again for doing this.

RBH said...

Martin Labar wrote

It's probably important to distinguish between the proposed or actual mechanisms of evolution (such as mutation and natural selection) and the proposed or actual results of evolutionary processes (such as new phyla from old). (Bolding added)

That's a problem I didn't know existed. "Phyla" are not biological entities in the same sense that, say, species are biological entities. Phyla are taxonomic constructions, not biological "things". All biological diversification events are, in their beginning, speciation events -- new phyla don't emerge from old phyla, new species emerge from old species.

The origin of a new phylum, say the emergence of chordates, was a speciation event. The descendants of one of those species, which might have been something like the fossil here, comprise the chordates, a reasonably successful clade. But the first chordate was a species of worm-like critter very similar to other non-chordate critters, and would not have been distinguishable as the original ancestor of a new phylum except in retrospect.

elbogz said...

I always found it curious that Genesis 1:28 would use the term “replenish”

28And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth

Something must have occurred before, that is not clearly pointed out in the text, to use the term “replenish”.

I guess it goes back to the theological question, was there a gap in time between Genesis 1 and 2. It seems that there must have been, and therefore all of evolution could have occurred and not be in conflict with the scripture.

The evolution of Satan or the serpent is also of interest. Chapter 3 of Genesis, he’s already on earth, and elsewhere we find the whole history of the fallen angels and that must have occurred. “prior” to Adam and Eve. Again, leaving much time for the earth, to be void and without form.

Steve Martin said...

Thanks. I’ll check those out. I will be updating my recommended internet resources shortly (my definition of shortly) and will probably add these videos to the list.

Thanks for your link. Definitely good overview. On the fact that it is human evolution that is “the sticking point”, I couldn’t agree more. As has been said (Falk? Collins?), “the evolution of single celled organisms to multi-celled organisms raises few if any theological issues”.

As an atheist visiting a Christian blog, you are sure are playing fair :-). Thanks. BTW, I was sure someone was going to raise the issue of E6 being somewhat arbitrary – ie. it is a big bucket for everything we (ECs) don’t agree with. In some ways I could agree with this assessment and think we need to break that one down a bit. Still mulling that one over. For Harvey’s purposes though (presentation to a church group), this is probably the right definition.

I think there are lots of issues with literal interpretations of Gen 1 that demand mind-boggling hermeneutic contortions. Never thought of the “replenish” issue before, but that’s interesting.

Cliff Martin said...

elbogz said...
I always found it curious that Genesis 1:28 would use the term “replenish”

Actually, there is no basis in the original Hebrew for the KJV word "replenish" as we think if that word. The Hebrew word, maw-lay simply means "to fill". In the KJV, it is translated "replenish" 7 times, and "fill" (or similar words) nearly 200 times. Both the NIV and NASB translate it "fill" in Genesis 1:28.

Not that I am opposed to the concept of a Gap in middle of verse 2. The words "formless and void" are suggestive of judgment, and are used in that sense elsewhere in the O.T. So it does seem to be a possibility; but I do not look for a gap in order to explain the passage of ages of time as some do.

JJS P.Eng. said...

Good day Steve. An interesting post. I've never seen the issues of evolution organised in such a manner. I look forward to exploring your blog in further detail.

As an engineer, I have a special interest in the mechanisms of evolution - E3. (I am trying to track down Dr. Allen MacNeil's comprehensive list of NS & RM mechanisms, and once I find the source, I'll send it your way if you're interested.) My particular interest is in the properties and limitations of the mechanisms, or IOW, what can these mechanisms do and what can't they do?

I do have to take some issue with including the concept of Common Ancestry (E2) in the High Degree of Scientific Certainty (HDSC). If by HDSC you mean the scientific consensus accepts this, then there's no issue. But if you mean that there's a HDSC in common ancestry based on the evidence, well I believe Drs. Gould (sudden appearance and stasis), Doolittle (Multiple Common Ancestors), and Koonin ("bush" of life) would disagree, and this is just a short list of dissenters. Plus, IMO, the fossil evidence and the "speciation" evidence do not support common ancestry, either.

Sorry for missing the earlier discussion as I just found out about this blog. Cheers.

Steve Martin said...

Welcome. I’d definitely be interested in that list – I remember seeing something like that once, and then couldn’t find it again later when I really wanted to refer to it.

I’m not going to debate the evidence for common descent. (It would probably just end up in a link war). But, from my own reading (check out my selected bibliography), I guess I’m pretty comfortable with the evidence. You may want to check out Stephen Matheson’s blog “Quintessence of Dust” at http://sfmatheson.blogspot.com/ .

My own interest is more in the theological implications anyways. Most of the theories that explain the fossil record & genetic evidence (eg. multiple common ancestors) are equivalent from a theological point of view.

Also, checked out your own reading list. Have you read “Perspectives on an Evolving Creation” by Miller yet? If not, check out my review here: http://evanevodialogue.blogspot.com/2007/05/grappling-with-evolving-creation-read.html .

JJS P.Eng. said...


Fair enough. I can respect you wanting to keep discussion within the bounds of this blog. I personally encourage debate and exchange of ideas on this, which is a reason I started up my blog (apologies for the cheap plug ;) ).

Here's the link (you need to scroll down a bit). What I also need to follow up on is this so-called concept of "engines of variation". Sounds interesting.

Steve Martin said...

Thanks for the MacNeil link. That was good. Actually, I don’t think I ever saw the original before – just someone copying the list.

RBH said...

JJS P.Eng. wrote

But if you mean that there's a HDSC in common ancestry based on the evidence, well I believe Drs. Gould (sudden appearance and stasis), Doolittle (Multiple Common Ancestors), and Koonin ("bush" of life) would disagree, and this is just a short list of dissenters. Plus, IMO, the fossil evidence and the "speciation" evidence do not support common ancestry, either.

I'll restrain myself, also in deference to Steve's point, and confine myself to remarking that anyone who can find doubt about common ancestry in Gould's "sudden appearance and stasis" (which I take to mean punctuated equilibrium theory) really needs to read what Gould (and Eldredge) actually wrote. JJS might start with Gould's Punctuated Equilibrium, which is Chapter 9 (separately published) of his doorstop The Structure of Evolutionary Theory. If JJS can find anything in that chapter -- any evidence -- that contradicts or casts doubt on common ancestry I'll eat The Structure of Evolutionary Theory.

The others JJS mentions deserve comment, too, but as I said, I'll restrain myself. I'll just whisper molecular phylogenies. :)

JJS P.Eng. said...


You bring up interesting points which I would love to respond to. However, I unintentionally "hijacked" another blog, and I will not do so again. So I propose that we move the debate to my blog here. I've reserved the first comment for you. Please re-post your comment above (sans restraint - just bring it, man!), and we'll go from there.

The only restriction I'll impose is to keep the discussion respectful.

"Keep your stick on the ice"
-Red Green

RBH said...

I'll repost it there now, and then be back in a day or so. This weekend is pretty full for me. Thanks for the invitation.

gluadys said...

I have a tiny quibble with Harvey's comment on mechanisms.

"Genetic variation is the fact that (due to mixing of parental genes and to mutations) children have different genes and different traits."

Only the mutation aspect is really important for evolution as this is what creates the variability in genes. Without this variability, the "mixing of parental genes" would be irrelevant, because all the genes at a given point in the genome would be the same in all individuals.

It is common to see a confusion between the variation in individuals due to the independent inheritance of different traits and the variation in a species that arises because of the simultaneous existence in the gene pool of different versions of the same gene. The latter is the key factor affected by mutation and natural selection.

Stephen Douglas said...

Wow - Gluadys? From Christian Forums? Didaskomenos here :)

gluadys said...


I've had this blog bookmarked for quite a while. Finally getting around to giving it the attention it deserves.

Steve Martin said...

Hi gluadys: Welcome. Re: mutation as the important factor in evolution. I agree that without mutations the mixing of parental genes would be irrelevant, but I do think that sexual reproduction adds quite a bit to the evolutionary process. Maybe we could think of mutations as the spark and initial fuel, with “the mixing of parental genes” being a significant addition of fuel.

gluadys said...

That's not bad. In "The Co-operative Gene", biologist Mark Ridley points out that sexual reproduction accelerates the elimination of undesirable mutations and the spread of desirable mutations through the population.

I noted the difference because I have often seen a "bait-and-switch" technique used on anti-evolution sites in which a question about the variability of genes is answered by reference to the combinatorial variations of several genes.

So while both have their place, it is important not to conflate them.

Martin LaBar said...

Thanks. I'd forgotten this post. (And a lot of other things!)