Darwin's tree of life

It appears to be natural for the human mind to find order and pattern in the world around us. We are actually quite good at classifying things, thereby emulating Adam naming the animals (Genesis 2.19-20).

There will be differences, naturally, in the ways we understand these patterns. Consider the colours of the rainbow — we understand them as a sequence governed by the laws of physics. My son has always had an interest in machines, and he recognises the historical development of farm tractors — a sequence best understood in terms of intelligent design. Most families are able to put together a genealogy going back several generations — this is a sequence based on ancestor-descendant relationships. Geologists refer to Mohs scale of mineral hardness which ranks common minerals in terms of what can scratch what — a purely functional sequence.

Chain of Being

Since the time of the ancient Greeks, objects in the world around us have been placed in a sequence called the ‘Great Chain of Being’. As originally conceived by the philosopher Plato, everything has a place and a purpose. Although the details varied with time, the key elements of the idea continued through the centuries. The chain connected low and insignificant objects with the highest and grandest. There was a gentle gradation from one object to the next. Although medieval philosophers and theologians debated the ‘Chain’, they mostly liked the concept. When the Royal Society was formed, Thomas Sprat, in his History of the Royal Society (1667), wrote that the task of members was to retrace the steps of creation and ‘to follow all the links of this chain, till all their secrets are open to our minds’. I find an analogy here with the children’s story about the camel and the tent — it found a way of getting its nose inside — so also this way of thinking about the world became accepted and welcomed by Christians.

To cut a long story short, the distinctive emphases of the Great Chain of Being made it easier for Darwin and his fellow evolutionists to gain acceptance of the theory of evolution by natural selection. The concept did not need to change very much: it still went from low and insignificant (single celled life) to grandest (man), the steps were all connected (common descent) and gradualism prevailed (natural selection of small variations). It allowed advocates to retain a sense of purpose if they wanted it because there seemed to be a progress in complexity, in intelligence and in fitness. Darwin replaced the Chain with a Tree: ‘the great Tree of Life, which fills with its dead and broken branches the crust of the earth, and covers the surface with its ever-branching and beautiful ramifications’.

Elusive evidence

Of course, Darwin claimed to support his theory with data, but the key evidences he needed were elusive. He needed to demonstrate gradualism using fossils, but he could not. He appealed to the extreme imperfection of the fossil record — a claim which has been convincingly falsified as the rocks have yielded more and more secrets. He needed to show how complexity could emerge, but observed changes in morphology of animals and plants fail to deliver Darwinian answers. The sense of progress was always an illusion: Darwin’s thinking was thoroughly materialistic and he always resisted interpretations that suggested divine guidance.

Discontinuity

How should we think about these issues? First of all, sequences do not always point to ancestor-descendant relationships (as the first paragraph above has shown). We may be identifying patterns that reflect design. This is how the Father of biological classification, Carl Linnaeus, understood his work.

Secondly, we are under no obligation to imbibe a conceptual model associated with the Great Chain of Being. Although Christians have adapted it for their own purposes, they appear to have let the camel take over the tent! The real test is whether this concept is compatible with the biblical way of understanding the world. This test reveals a mismatch! The Bible emphasises discontinuities between plants, sea creatures, land animals, birds and humans. God created living things to reproduce after their own kind. This foundation for discontinuity is laid in Genesis 1 and is reinforced at the time of the Flood (the animals entering the Ark of Noah). The theme is taken up again in the Levitical laws and further reinforced in the New Testament.

Mankind

Mankind provides a good case study. From Adam and Eve have come all the races of men — Mongoloid, Australoid, Negroid and Caucasian. Humanity displays many different traits: colour of skin, shape of nose and eyes, colour and texture of hair, bone thickness, body proportions, and so on. Variation within a created kind is warranted from biblical revelation — fixity is not. Examples of variation in the living world are just as compatible with creation-based biology as they are with evolutionary biology. However, the discontinuities between mankind and apes is marked. Despite years of research by people intent on demonstrating continuity, the aggregated results confirm that the gulf shows no signs of being bridged. This finding is only compatible with creation-based biology.

Educators who introduce their students only to Darwin’s Tree of Life are perpetuating a cultural icon, not teaching science. Creation-based biologists have long suggested a better way: compare and contrast the Tree of Life with the Forest of Life. Are the patterns we see in nature better modelled by a tree or a forest? This is the route to a richer and more stimulating analysis of the evidence.

Dr. David J. Tyler,
secretary of the Biblical Creation Society;
author of The Guide. Creation — Chance or Design?
Blogs at http://www.arn.org/blogs/index.php/literature

Darwin's tree of life

Chain of Being

Elusive evidence

Discontinuity

Mankind

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