What is Science?

Several years ago, Michael Ruse wrote a book about the Arkansas Creation Science Trial of 1981. The title of the book was "But Is It SCIENCE?". The basic thrust of the book was whether "creationism" qualified as a scientific method. Ruse's answer was "no". Niles Eldredge starts off the discussion about evolution with a look at what science means. Science needs to be testable, and to make predictions of what we might expect to observe in the world around us. Sometimes these predictions turn out to be true - and we hang on to our idea, and sometimes the predictions consistently fail - and we must abondon our hypothesis.

Is Evolution Science?

Eldredge says that "evolutionary theory" actually involves two different sets of ideas:

1. Descent from a common ancestor of all living organisms.



2. Mechanisms of how evolutionary processes work.

The first is well documented by the fossil record, but for the second there are lots of disagreements about HOW the actual process works. Many creationists take debates about this second group of ideas to somehow invalidate the solid evidence for the first.

What Predictions Can Evolution Make?

Eldredge says that there are two grand predictions made by evolutionary theory:

The first prediction is that evolution did occur, all of life should be organised into heirarchical fashion of groups within groups. For example, all cats are related to each other, and are also related (though a bit more distantly) to other mammals, and are even more distantly related to other animals, and share some things in common with all other living organisms (e.g., cells, biochemical pathways, etc.).

The second prediction is the fossil record - we would expect to find a progression starting with simpler, smaller organisms, with the gradual addition of more complex (and sometimes larger) organisms, over long periods of time. This is indeed what is found in the fossil record. This is discussed in more detail the in the next section.

The Fossil Record.

Eldredge points out that there is a difference between the question of how life originated, and that of what happened after life got started. I think he does an excellent job of explaining genetics, especially considering that he is a geologist by training. (I only have one very small criticism - he seems to confuse monoploidy - that is, when the cell has only one copy of each chromosome - with "single stranded" DNA (page 36 and 40). But this is a small and trivial point compared to the grander picture which he paints of the history of genetics and how what we see in the fossil record is really what we would EXPECT to see.) In all fairness, I think Eldredge does an excellent job of explaining the development of genetics, and its implications for what one might expect to see in terms of the history of evolution, in his earlier book, "The Patern of Evolution".

I found the discussion of the "Cambrian Explosion" to be a quite good and clear explanation of this event, by someone who knows the subject area. The Cambrian explosion has become a favourite topic of creationists, because of the (relatively) sudden appearance of many types of complex animal life forms. Eldredge studied trilobites, which are some of the oldest Cambrian fossils. "Why are some of the oldest forms of animal life that are found in the fossil record also some of the most complex?", he asks. He then goes on to tell of the more recently discovered Ediacaran fossils, which contain fossils of animals before the Cambrian explosion, and give clues to what life was like before then. Later, Eldredge adds:

"Thus, predictably, we have begun to fill the gaps; we now know that the advent of complex multicellular animal life did not occur overnight (nor in a single biblical day), but rather took place in a succession of events spanning 160 million years." (page 44).

Partly out of my own curiousity, and also for the sake of added clarity, I have put together a "timeline" of some of the major events of the fossil record. I have put my own favourite events in, and probably have neglected ones that other people would consider important. Or course, the dates are approximate.

Evolutionary Mechanisms.

Briefly, it is well known that natural selection is the mechanism underlying adapative change in evolution, and that "the evolutionary process is complex, involving ecological and physical environmental factors in addition to the genetic components that underlie the origin and maintenance of genetic variation, as well as selection for stasis and adaptive change". (page 64).

Eldredge chooses to give a historical approach to the discussion of the mechanisms of evolution, ranging from Darwin up to the present. Of course, he goes into a detail about how he and Stephen Jay Gould proposed "punctuated equilibrium", and says that when they published their paper in 1972, they thought that this was only for perhaps a small subset of species, and had not realised that in fact long periods of stasis applied to the "vast majority of species". The first book I read written by Niles Eldredge was "Reinventing Darwin", in which he does an excellent job of describing what punctuated equilibrium is, and how it fits in not only with what is found in the fossil record, but also what we see in the world around us today.

The main "driving force" in evolution is a change in the physical environment which disturbs ecosystems and species. Eldredge more fully explains this in his "Pattern in Evolution" book. In the Table above, I have added the "5 great extinctions" in the fossil record, and it is worth noting that each of these is followed by the expansion of the survivors. This is a trend that often happens in nature, when some natural tragedy, such as a hurricane, destroys most of an ecosystem. Soon after, one can see the radiation of new life forms to fill the now vacant ecological niches.

Young Earth Creationism.

Many of the typical creationists arguments are discussed here, such as whether "evolution violates the 2nd law of thermodynamics", and how do we know that the rocks are really that old? The "young earth" creationists do not believe in the geological record, and they also think that all of what we see in terms of fossils is from Noah's flood.

Elderidge knows about the Creationists from personal experience - he tells of his surprise to discover that he was being quoted in the Creationists literature as saying that evolution has not happened. It turns out that someone had taken a comment completely out of context (at best) and distorted it to suit their purposes. I couldn't agree more with his comments about the creationists:

"Creationists hear what they want to hear because they believe what they want to believe. They obviously think that all this is fair in both love and war, and they see this as a culture war. But somehow I persist in the apparently quaint belief that lying, cheating, and distortion are inherently unchristian." (page 134).

Intelligent Design - neoCreationists.

Some people really do not like the idea of evolution, but also realise that there is abundant scientific evidence that life evolved. Some of these have found solace in the idea of "Intelligent Design" - that is, the concept that life is so complicated, an Intelligent Designer must have been responsible for creating life with "human-like intelligent design".

There are several different flavours of the "Intelligent Design" (ID) movement, ranging from Phil Johnson, who thinks that humans did not evolve from a common ape ancestor, and that ID should be taught in the public schools INSTEAD of evolutoin, to people like Michael Behe, who claim they believe in evolution by common descent, that the world is 4.5 billion years old, but that only the "complex biochemical systems" require the intervention of an "intelligent designer".

Culture Wars & Christian Ecology.

Eldredge alludes to the ecological crisis in the introductory chapter of the book:

"Creationism is just one of the two important social issues that have intersected my life as an evolutionary biologist. The other one is the horrendous loss of species - an event now gripping the planet that some have called the Sixth Extinction. Human beings are laying waste the world's ecosystems, and in so doing driving something like thirty thousand species of microbes, fungi, plants, and animals extinct every year. That's by far the fastest rate of ecosystem destruction and species loss since the time when the dinosaurs and so many different kinds of life were abruptly erased 65 million years ago - the result of a collision between Earth and extraterrestrial objects, and huge volcanic eruptions as well." (page 15-16).

In this last chapter is where I think Eldredge makes some very good points, and even gives the religious people some good news, for once. He first makes a very good case that it is important to teach our children about science - how it works and how it is done. Sometimes teachers try to push their atheistic beliefs as "science". This is wrong, Eldredge says. Then he goes on to develop the idea that, although many would like for there to be a "culture war", between the evolutionists and creationists, in fact we really cannot afford this - especially with the looming ecological crisis.

"Nor do I think we can afford these stupid culture wars, with people like Phillip Johnson getting upset that his version of God seems threatened because scientists have discovered that life developed over 3.5 billion years ago on the planet and feel that they can explain how that happened through purely natural causes. Nor can we afford the arrogant intolerance of the scientists who claim that their science - evolution in particular - demonstrates unequivocally that there is no God ." (page 134).