Many things in this world evolve: they grow more complex and more powerful in a rather chaotic process where small local changes and selections add up, without an overall plan or design.

All of our technological advances, for example, such as the computer, have come about in this way. What is more, this is the only way possible. No team of specialists in the pre-computer age, no matter how bright, could have understood the detailed design of a modern PC, let alone create one. It really took 70 years of continuous research, production and use to reach the technical proficiency required to build a PC. Don't let yourself be fooled by documentaries about the "father of the modern computer", whoever they happen to pick; their contributions may have been crucial, but in reality, the whole development is far outside the vision and intellect of a single person.

While designs and planning seem indispensible along the way, it really appears to take evolution to give us anything new.

Other examples of things that develop by evolutionary processes:

  • natural languages (e.g. English, French, American English, Texan, Oxford English, computer jargon)
  • programming languages (e.g. C, C++, Java, C#)
  • file naming conventions (e.g. .*rc for the startup files of Unix applications)
  • shaving equipment (heavily protected through countless patents on all the "inventions" done underway)
  • music
  • our scientific knowledge of the world

In all these examples, the human mind is involved, and it can be argued that its power to invent and plan gives these developments their thrust. But they are all "evolutionary" in that their development isn't guided by any single overall plan or design.

When we look at life on earth, it seems to consist of systems of similar or even bigger complexity - and what is striking is that they, too, appear to arise through an evolutionary process. (I usually call this process "natural evolution", but tdent reminds me that that isn't a well-established term; so it would probably be better to retitle this node to the evolution of life or the evolution of species.) The hypothesis that the life forms found on earth were created through evolution was first argued by √Čtienne Geoffroy St. Hilaire, later proved by Charles Darwin and many others.

In this evolutionary process, no humans are involved at all, other than that they are supposed to be one of the results of the process. Therefore, we can't ascribe its progress to the human capacity to think and plan. This is what makes the hypothesis so interesting, for most of us seem to a strong feeling notion that complex systems are impossible without some intellect designing them.

The evolution of life is a well-researched subject. Careful scrutiny of relevant evidence, such as fossils and genes, has established many patterns in what we find, and also in how it appears to have come about. So we now have a body of knowledge that makes pretty accurate predictions about the observable world as far the evolution of life is concerned. For example, inside charcoal from the Carbonic age we won't find crocodile bones, but we may find other reptiles, or insects.

It is not the purpose of this writeup to explain these findings, or convince you that they are true. Instead, my point is that when we, laymen, discuss the idea of evolution, especially when we disagree, it would serve clarity to call different concepts by different names:

  • the idea of evolution in general: the development of certain complex things through many local changes, without an overall plan or design; see the examples;
  • the evolution of life on earth: the idea that the life forms on earth are subject to such a process, and were created through it from other life forms;
  • particular mechanisms by which this process is supposed to happen; for example, Darwinian evolution, which holds random mutation of genes and selection of specimina by environmental conditions responsible.
Since I was thinking about this on the way here (where here is, you don't kneed to know) it may be valid to add another writeup.

The confusion evident in the node The theory of evolution is not a valid theory is probably because of the different meanings of the word evolution. Here is the simplest definition:

Evolution = Change over time

In this sense, everything evolves - yes even Everything :) Rocks evolve, cars evolve, keyboards evolve. I don't just mean successive keyboards are different (and possibly better). It also covers change to an individual object - the gradual rusting of a wrecked car, the weathering of a rock.

However the evolution of a system is much more complex than that of a 'simple' object. If you watch a rock for 100 years you will not learn very much about rocks. Watch a paramecium for five minutes and a whole range of behaviours is visible. 'Natural' evolution could be the movement of a single cell as much as it is change of a global ecosystem. The most important feature of life is that it operates on a range of scales - both time and space. Similar principles apply to cells as apply to organisms or superorganisms. Biological systems both respond to external changes (the weather) and to internal ones (hunger).

If life was predictable, it wouldn't be complex enough.

tdent points out that laws of nature don't evolve.

See : Evolution is only a theory; it hasn't been proved.

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