evolution and design

evolution, its weaknesses and its critics

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Check out the main criticisms of the theory of evolution and the main scientific answers. Does the alternative theory of Intelligent Design stack up as a believable explanation? How does all this affect our conclusions about God and the meaning of life?

In the clues section, we look for clues to the answers to the big questions of God and meaning in life. Each topic discusses the facts and arguments believers and unbelievers use to support their viewpoint - a world of philosophy and ideas in just a few pages!

reason & belief is concerned mainly with the meaning of life and how we live it, not with scientific matters. But in considering the nature of life, one cannot avoid facing questions raised by evolutionary science. This is a brief rundown of how I have approached this question and my conclusions about the common objections to evolution.

evolution - what's all the fuss about?

A summary of the findings of mainstream evolutionary science, is provided in this statement by the InteracAdemy Panel. It includes such conclusions as the age of the earth (about 4.5 billion years) and of life on earth (more than 2.5 billion years), the evolution of life via mutation and natural selection, and the use of the scientific method to investigate such matters. Scientists generally believe that the gradual evolution of life over a long period of time is a proven fact, but that the exact mechanisms and processes remain theories. For references on evolution generally, see here.

However many people, especially believers in various religions, contest some of these facts, or the common interpretations of them. Here is a summary of some of the main areas of contention.

"gaps" in the fossil record

Evolution is essentially a slow and gradual process of accumulation of small changes, and the fossils discovered so far only record a small percentage of the plant and animal species which have existed. One might expect the fossil record to include fossils randomly from the entire process of evolution, however, while most major groups and species are represented among the fossils, relatively few transitional fossils have been found to fill the gaps. Critics of evolution argue that this invalidates evolution as a process that produces the complexity of life we see around us.

But evolutionists explain this situation as follows:

  • One would not expect large numbers of fossils to be found because of the particular conditions required for fossils to form and the relatively small percentage that are likely to be unearthed.
  • Because of variations in the types of plants and animals, and the geographic conditions in which they lived, one would not expect an even distribution of fossils across all species.
  • Some evolutionists, notably the late Stephen Jay Gould, believed the fossil record indicated a "punctuated equilibrium" in which periods of little change were followed by periods of great change, rather than a slow linear process.
  • Transitional species may not have been in existence for long periods of time, and hence would naturally be less likely to appear in the fossil record.
  • Many transitional fossils have been found, including some that had previously been identified as most damaging to evolution.
conclusion

It seems this objection is reasonably answered, although continued lack of success in finding transitional fossils may eventually throw doubt on current understandings of processes. Check out references on gaps in the fossil record.

the Cambrian explosion

The fossil record for the Cambrian Period, more than 500 million years ago, shows the relatively sudden appearance (over a period of perhaps 5-30 million years), without previous ancestors or transitional forms, of most of the phyla known today. (Phyla are major groupings of plants and animals based on their body plan. There are about 35 phyla today, and most apeared, or are believed to have originated, in the Cambrian Period). At first sight, this appears contradictory to Darwinianism, and very difficult to explain.

The Darwinist responses include:

  • Contradiction - it simply didn't occur, it isn't possible, and the evolution of new phyla actually took longer than the current fossil record may suggest.
  • There were earlier ancestors, but their fossils have not been preserved because they were not organisms that commonly left fossils.
  • There was a long period before the Cambrian where genes developed to a certain stage, which then allowed the new phyla to develop relatively quickly.
  • There were, perhaps, special conditions (for example increased oxygen levels) which led to this rapid growth.
conclusion

This still looks to be a difficulty for evolutionary theory - the several different explanations indicate that a satisfactory understanding has not yet been reached. Nevertheless, it seems wise to give science the benefit of the doubt here. Look up references on the Cambrian explosion.

transition processes

The evolution of life requires numerous small changes to cumulatively lead to new and more "advanced" species. And for natural selection to operate as a mechanism for this change, every step in the process must confer a survival advantage so that the organism survives to allow the next step in the process. Much debate centres around whether plausible processes can be found that explain the evolution of complex biological body parts, such as the eye.

Of course it isn't possible to demonstrate the evolution of new species with new biological functions in a laboratory, so "demonstration" generally involves understanding how the new organism is related to its ancestor organism, determining what changes in anatomical structure are required, showing from the fossil record or some form of modelling that such changes could have occurred, and demonstrating how each of the major steps had survival value (perhaps by showing homologies - examples of similar structures which "work" in present day organisms).

Using such processes, evolutionary scientists have explained many difficult to imagine transitions. Many others remain to be explained, but it is claimed that this is only a matter of time.

Just over ten years ago, biochemist Michael Behe introduced the argument that the structure of some living cells is "irreducibly complex", meaning that their functioning is so dependent on all of their components that they could not evolve from a simpler structure. This is a more significant challenge to evolution, but it is generally accepted that he has not yet demonstrated his case. For example, evolutionists claim to have shown workable transitions to systems, such as the bacteria flagellum and the cilium (two biological "machines" used for propulsion) which Behe claimed were irreducibly complex. It remains to be seen whether the concept of irreducible complexity can be shown to be true in any situation.

conclusion

This one is tricky to assess. Scientists often claim that transitional processes have been demonstrated or proven, when in fact they have generally only been shown to be feasible - they cannot be established by the normal scientific method of repeatable observation (see quote below from WF Doolittle). So, it seems to me, the best that can really be claimed is that if we assume there can have been no outside interference (e.g. from God), then some transitional process must have occurred, and the current proposals are the most likely options. See here for references on the transition processes and irreducible complexity.

the origin of life

The evolution of life is one thing, but evolution requires the existence of a primitive organism to begin the process. (Strictly speaking, the theory of evolution does not address the origin of life.) How did life originate?

It is not easy to define the characteristics of life, but the following abilities are generally part of the definitions: to process energy to perform other functions; to respond to stimuli and adapt to its surroundings; to grow and regenerate worn components; and to store information that allows replication. For the earliest forms of life to be able to perform these functions is no mean feat.

Hydrogen, oxygen, carbon and nitrogen have to be formed into amino acids. Scores of amino acids must then be linked together in an appropriate sequence to form protein molecules and the nucleic acids which make up genetic code. Then a hundred or more protein molecules must combine to form a living cell. That such complex processes could occur naturally is almost beyond belief, and critics of evolution can outline many barriers that must be overcome, and for which current explanations do not appear to be satisfactory.

Science has not as yet been able to demonstrate how it all might have occurred. Many proposals have been examined and none has been found likely at this stage. The methods being used for this research cannot yield the near-certainty that science usually seeks, and some critics will undoubtedly continue to argue that natural forces alone cannot explain the origin of life. Francis Crick, one of the discoverers of the structure of DNA, wrote in 1981: "The origin of life appears to be almost a miracle, so many are the conditions which would have had to be satisfied to get it going."

Nevertheless, scientists have made considerable progress on this research and are confident that they will one day be able to demonstrate the process by which life arose. Biologist W Ford Doolittle recently wrote: "Origins-of-life science is still very much a work in progress. The sensible bet is that chemists will close this particular gap [the formation of replicating RNA molecules and the first step in life beginning] with feasibility experiments (maybe even several different kinds of feasibility experiments) within the next decade."

conclusion

Abiogenesis, the beginning of biological life out of chemical components, remains even more uncertain than other transitions discussed above. Those committed to a belief that only natural processes can be involved will continue to strive for a feasible process, whereas those with wider beliefs may well continue to question the evidence. See here for references on the origin of life.

explaining the facts

intelligent design?

Intelligent Design argues that natural selection is insufficient to explain some evolutionary processes, including those discussed above, and that design by intelligence is a more reasonable explanation. Intelligent Design does not claim that the source of that intelligence can be known by scientific means, but obviously its proponents generally believe that intelligence to be God.

I do not regard "intelligent design" as necessarily the same as "creationism", as some people do. The key for me lies in whether the factual findings of science are accepted or not. Creationists, and some proponents of intelligent design, do not accept the findings of mainstream science on matters of fact. However others of those advocating intelligent design do accept the factual findings of mainstream science (e.g. the big bang, the ages of the universe and of earth, the evolution of species by natural selection, etc), but they believe these facts are best explained by an intelligent cause rather than natural processes.

It seems to me that the intelligent design movement has not yet demonstrated its propositions in a scientific manner, although this does not necessarily mean they are untrue. But even if intelligent design is a true insight into God's actions, science cannot observe or experiment with those actions, so intelligent design's "proofs" consist of little more than incredulity about some postulated evolutionary processes.

It is therefore difficult to see how intelligent design can ever be verified scientifically, and hence it is unlikely to ever be recognised as science. It is possible that science will eventually explain how many of the currently unexplained processes occurred, leaving intelligent design with a dwindling impact. But even if explanations are not found, naturalistic scientists will be required by their beliefs to keep believing and searching for explanations. It is hard to see a big future for the Intelligent Design movement. Check out references on intelligent design.

theistic evolution

However this does not necessarily leave God out of the picture. Many theists, while accepting that the intervention of God is not necessary to explain the steps in the evolutionary process, nevertheless believe that God set the process up, and that he is involved in many less obvious and discernible but unprovable ways in human history and life. Many believe there is good evidence for this, for example, that God's intricate design of the universe is seen in the physical laws and the values of many constants within those laws which appear to be fine-tuned to lead to human life (as discussed in "it looks like it was designed" and "a rare earth?"). Look up references on evolution and faith.

doubts about evolutionary science

Most science depends on observation of the world or of controlled experiments, in a systematic manner which leads, in the end, to a high level of statistical confidence in the results. However evolutionary science has more limited opportunities to observe of experiment, and must often proceed by less direct methods. The following (from The Origin and Early Evolution of Life by W. Ford Doolittle, Biochemistry Professor, Dalhousie University, Canada) is instructive:

Questions about the past - whether in cosmology, geology, paleontology, archaeology, or human cultural and political history - are different. We cannot do experiments in the past, so any attempt to reconstruct it must be based on indirect and inferential methods.

Evolutionary biologists who seek to reconstruct life's history have three such inferential methods: (1) comparisons of the properties of living species; (2) study of relics, such as biological and chemical fossils, or apparently primitive features retained by modern cells; and (3) feasibility experiments. The comparative approach can in principle take us back to the last common ancestor of all currently living things, and the fossil record (biological and chemical) may go a bit further, to something close to the first cells. For the origin of earthly life itself, and perhaps even up through the appearance of the earliest true cells, we must rely on feasibility experiments. In these experiments, hypotheses about what might have happened in the past are shown to be plausible by demonstration that similar events can be made to happen today, in the lab.

Certainty and completeness in reconstructing life's ancient history will never be possible, nor indeed are they possible even in reconstructing the very recent history of a nation or society. But it would be foolish to deny that we already know a tremendous amount, or that what we do know provides a compelling story of how past became present.

Science assumes that it is the only way of explaining the origin and evolution of life on earth, and specifically excludes God and the supernatural from its processes. Therefore, no matter how unsatisfactory explanations about any part of the process are, especially about the beginning of life, evolutionary scientists will nevertheless assume that a naturalistic explanation will be found. However the above quote suggests that the processes which originated life probably cannot ever be "proven", but is a necessary corollary of a naturalistic worldview. There seems to be an inconsistency or a circular argument here.

We have good reason to trust science generally, but the fact that such doubts and questions tend to be shouted down or ridiculed rather than addressed leaves me feeling a little uncomfortable.

humility rather than hubris

This brief survey suggests that both intelligent design and evolutionary science may deliver less than their most enthusiastic supporters claim, especially when applied to the long-ago questions of the origin of life. It appears that intelligent design cannot be demonstrated scientifically to be true (i.e. it is unverifiable), and while theories about individual evolutionary processes can be verified and falsified, the basic assumption that the whole evolutionary process can be explained in natural terms appears to be unfalsifiable (i.e. no matter what, scientists will keep on saying there is a naturalistic answer). To be sure, science explains a lot, and we can happily accept its findings, but a degree of humility is preferable to hubris when drawing conclusions.

conclusion

On the basis of the above discussion and the references, it is safest to conclude that there is no reason to significantly argue against the findings of evolutionary science. It may be that some aspects of current thinking about evolution, and especially about the origin of life, are in error, and certainly some are presently unknown, but I do not believe this materially affects the main lines of discussion in reason & belief. There are more important matters for non-scientists to consider without arguing about evolution. It would therefore be helpful if evolution, or any other scientific matter, was considered as the explanation of how processes on earth "work". We are each then free to decide if we think God, something else, or nothing, is the best explanation of the cause "behind" the processes.

links

  • If you want to think about the implications of evolution for life and faith, go to life and nothing but.
  • If you would like to consider what we can learn about the meaning of life from looking around us at the universe and looking within ourselves, go to clues.
  • Check out the references for evolution and design.
  • Return to the page you came from.