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Thursday, September 15, 2005

I believe in evolution. So do you! part 2

Some people call the meanings of evolution given in the first part -- namely change, natural selection, and speciation -- microevolution. Many Christians believe that all of these occurred by natural processes, although they usually believe that humans are not here solely because of natural processes. They also believe that these processes, like gravity, were designed -- built into the universe by an intelligent Creator, who had foreknowledge of the consequences. Other Christians would disagree, believing that most or all speciation was not the result of natural processes, but of miracles. However, I think all Christians who have honestly thought about it would agree that at least a little change and natural selection have occurred, and probably that at least some species might have arisen by natural selection. There doesn't seem to be any doubt that varieties have so arisen. Therefore, in at least one of these senses, all people believe in evolution.

Now, what about macroevolution? There are at least three types of this.

Another meaning of evolution is phylogeny, the origin of large groups of living things. If, for example, both birds and mammals are descended from reptiles, that would be phylogeny.

Most biologists believe that phylogeny occurred, by natural processes. If pressed, such people would probably agree that it is more difficult to imagine, say, how feathers arose from reptilian scales, than to imagine a scenario for dogs to have arisen from wolves. It is more difficult to believe that natural selection was solely responsible for phylogeny than for speciation. The amount of change needed is considerably greater, and perhaps ordinary mutations could not have produced the variety necessary. It is difficult to produce a scenario that would explain how an organism that had a skin structure intermediate between a scale and a feather would gain any advantage from having such over a relative with scales. In fact, half-feathers might well have been a disadvantage.

There is some fossil evidence for phylogeny by natural means.

Many Christians have difficulty believing that phylogeny took place by natural processes.

Some Christians who do think so say that the days of Genesis 1 were really long periods of time. Maybe so, but, if that's true, it's more complicated than that. Why? Land animals appeared during the sixth day. Birds and water animals appeared on the fifth. Most biologists believe that birds evolved from reptiles, which were land animals. Genesis 1:21 says ". . . God created the great creatures of the sea . . ." on the fifth day. This sounds like it includes whales. However, most biologists believe that whales are descendants of land-living mammals. In both cases, we have something appearing after its descendant. So, although it is possible that the days of Genesis 1 are meant to represent long periods of time, either there are problems with the scientific evidence, or the long periods of time aren't given in consecutive order, and may even have overlapped.

Yet another meaning of evolution, unfortunately, is the origin of life.

Most biologists believe that life emerged from non-living things. This could not have happened by natural selection, at least not until the first living things reproduced. Darwinian natural selection relies on differential reproduction of selected types, and you can't have that without reproduction. Therefore, if life originated without God's miraculous intervention, it wasn't by evolution in the usual sense. What those who doubt God's work in life's origin really believe in is a naturalistic, as opposed to supernaturalistic, origin of life.

Also notice that, contrary to an apparently impossible to eradicate creationist belief, the theory (in the technical sense) of evolution is most definitely NOT a theory of how life originated. The latter is a matter for biophysics and biochemistry, not evolutionary biology. Evolution (in the neo-Darwinian sense) started after the origin of life on earth, and cannot therefore possibly be invoked to explain such origin. Nor do scientists ever use the theory for that purpose! - Massimo Pigliucci, entry, "Creation, Evolution, and the Nature of Science," of Jan 16, 2005, in his (mostly) Rationally Speaking blog, emphasis in original.

Pigliucci is a harsh critic of Intelligent Design, which, to him, is a form of creationism, and of supernaturalism in general. His statement is correct, but I must observe that "creationists" aren't the only ones who believe that the theory of evolution is a theory of how life originated. Many naturalists seem to think so, too, and, unfortunately, most biology textbooks promote this idea, perhaps unintentionally. I agree with Pigliucci that the theory of evolution is not a theory of how life originated.

Even if life really did originate naturalistically, it would be hard to be able to prove this, or to determine exactly how this came about, because of the immense span of time between now and then, and the difficulty of knowing exactly what the conditions were at that time.

Most Christians have difficulty believing that life arose by natural means. I suppose that any who do would say that God created atoms with emergent properties. That is, He planned how life would arise by chance processes, because of the way He designed atoms, and the way He designed the early earth.

A final meaning of evolution, even more unfortunately, is the origin of everything. I don't see how this could have happened by natural selection, and I've never read anyone else who did.

If Genesis 1 means anything, it means that God began the universe. Genesis 1:1 doesn't say when this was, or how or why it happened. It does say Who did it. That fact must be more important than when, how, or why. However the universe arose, we would not expect there to be much, if any, scientific evidence for the means by which it appeared. It is possible to believe that everything somehow began to be something. However, it takes an act of faith, just as believing in a supernatural Creator does. (Hebrews 11:3) Most people don't seem to recognize this. Some do. As Michael Shermer, frequent critic of supernatural beliefs, put it: "In conclusion, I believe, but cannot prove...that reality exists and science is the best method for understanding it, there is no God, the universe is determined but we are free, morality evolved as an adaptive trait of humans and human communities, and that ultimately all of existence is explicable through science." This is one of many responses to Edge's World Question for 2005, which was: "What do you Believe is True Even Though You Cannot Prove it?"

Schermer, a prominent self-confessed atheist, is to be commended for his honesty. He can't prove his world-view. He just believes it. As I understand Hebrews 11:3, I'm in the same position, and so are you, although our world-views may not be the same as Schermer's. So why does Schermer believe as he does? I think Ian Barbour put it very well, and honest naturalists (he uses materialists, instead) would agree with him (I have read statements by naturalists which show this.):

…both scientific materialists and biblical literalists have failed to recognize significant distinctions between scientific and religious assertions. The scientific materialists have promoted a particular philosophical commitment as if it were a scientific conclusion, and the biblical literalists have promoted a prescientific cosmology as if it were an essential part of religious faith. Ian G. Barbour, When Science Meets Religion: Enemies, Strangers, or Partners? San Francisco: Harper San Francisco, 2002, p. 36.

The philosophical commitment of the naturalist is that there is no God, no design, no plan, no pattern. They can believe it, but they can't prove it. I believe that there is a God, a design, a plan, and a pattern. I can't prove it, either. Hebrews 11:3 says that I can believe it, and I do.

One reason for making evolution a big deal is that it's easier to get people to pay attention to you, even support you financially, if you polarize a topic. (Just look at our political process.) Concerning evolution, it's easier to get an audience if you say something extreme, such as that all the science professors at a nearby university are atheists, or that all the conservative preachers in the county are ignorant, anti-scientific yahoos. Both things are said, sometimes because the speaker genuinely believes them, but, I am afraid, sometimes because the speaker wants to attract a following, knowing full well that there are believing scientists at many universities, and intelligent, open-minded (about scientific matters) preachers in conservative churches.

Such extremism does not help anyone, except maybe the extremists. Saying "I don't believe in evolution" is seldom, if ever, completely true. It isn't a clear statement, and may indicate ignorance or muddy thinking, or even deliberate obfuscation. It would be better to say "I believe that humans were specially created," or "I don't believe in macroevolution," or "I'm a young-earth creationist," or exactly whatever the speaker or writer does believe, or not believe. Not everyone is a naturalist -- I'm not -- but everyone believes in at least some evolution.

1 comment:

Martin LaBar said...

The quotation from Pigliucci, given in the post, refers to a web page that is, for some reason, no longer available.