The "argument from design"…
The "argument from design" for the existence of God is well-known, and can be summarised as follows:
- Every design has a designer.
- The universe has a complex design.
- Therefore, it has a designer.
It's an old argument; pre-Christian, in fact. In the first century BC, Cicero pointed out that a sundial or a water-clock has a designer, and argued that a universe which contains sundials and water-clocks, and their designers, must itself have a designer.
Nearly two thousand years later, the argument was being deployed in almost identical form, except that the example had been updated from a sundial to a watch. Anyone can see that a watch has a designer, yet the natural world contains countless examples of thing more complex and more finely balanced than a watch. How can they not have a designer?
The argument had changed so little by the early nineteenth century because, given the level of scientific knowledge up to that point, it was all but irrefutable. Even those who rejected almost every aspect of Christianity would concede that, yes, there must have been a creator. Many of them adopted a position known as Deism, which postulated a creator god who had no continuing involvement with his creation, and could not be known or approached.
The Theory of Evolution…
Charles Darwin (1809-1882)
All this changed after Charles Darwin postulated a mechanism by which well-adapted complex organisms can evolve without the need for a supernatural designer. In brief:
- Random mutation leads to the development of new traits in a species, capable of being inherited.
- Natural selection means that, if the new trait makes the individual better adapted to thrive in its environment, the individual is more likely to survive and to breed, so the new trait tends to be passed to later generations. By contrast new traits which do not make the individual better fitted for its environment tend to die out.
- Over long periods of time, the new traits become universal, so a species tends to become better and better adapted to its environment. Over very long periods of time, new species evolve, and those which are better adapted to their environment tend to supplant other species.
Darwin's proposal had gaps. He didn't, for example, understand the role that genetics played, but this gap was later filled by the work of Gregor Mendel. Other gaps have been similarly filled, and the evidence noted by Darwin has been supplemented by a wealth of further evidence. The Theory of Evolution, as developed by Darwin and modified by those who came after him, is now considered to be supported by abundant evidence.
But it is not universally accepted.
There are, as we know, Creationists who are simply not interested in the scientific method of acquiring knowledge. For them, the scriptural account of creation is comprehensively true and any scientific insights which are inconsistent with it must, by definition, be in error.
Intelligent Design is an entirely different matter. Proponents of Intelligent Design are not Creationists, and mostly reject the Creationist account. They aim to take a scientific approach to the question, and argue that the Theory of Evolution is incomplete and unsatisfactory, and that a better fit with the observed facts is the theory that life as we observe it is the work of a superlatively intelligent designer.
Intelligent Design theory does not specify who or what that designer is. It could, in principle, be a superior alien civilisation. In fact most proponents of Intelligent Design are Christians, and take the designer to be the Christian God, but they acknowledge this identification to be a matter of faith, not science. But they do assert that there is a scientific case for the existence of a creator of some kind or, at any rate, a scientific case against the Theory of Evolution.
Proponents of Intelligent Design have made a number of criticisms of the Theory of Evolution.
The first is based on the notion of "irreducible complexity" — the idea that many individual traits of any species only fit it for its environment when combined with other traits of the same species.
Take the familiar but non-biological example of the mousetrap. A mousetrap consists of just five parts:
- The plate, a wooden base which holds the mousetrap together, and keeps the other parts in the correct position with respect to one another.
- The hammer, the bit that actually hits the mouse
- The spring, which drives the hammer.
- The catch, which holds the hammer back until the mouse is in position.
- The trigger, which releases the catch and allows the hammer to strike the mouse.
This is not a very complex mechanism, but it is "irreducibly complex". That is, if you take any part of it away, the mousetrap will not work. It does not become a less effective mousetrap, one which catches fewer mice; it ceases to be a mousetrap at all.
There are many biological mechanisms which are similarly "irreducibly complex"; for example, the eye. It consists of several parts — the cornea, the lens, the iris, the aqueous fluid, the optic nerve, etc. Take away the optic nerve, and the eye does not become a less efficient eye; it is completely useless. But it cannot be that the cornea, the lens, the iris etc evolved, and then sat around waiting for the optic nerve to evolve. Without the optic nerve, the cornea provides no evolutionary advantage, and therefore would not have survived. How, then, can the eye — and many other similarly "irreducibly complex" biological features — have evolved?
The answer is twofold:
First, although the cornea is no use without the optic nerve, the optic nerve is certainly useful without the cornea. There are, in fact, creatures which have no eye, but do have an "eye spot", consisting of an optic nerve ending on the skin. They cannot see in the ordinary sense, but they can detect light, shadow and movement, and this provides them with an evolutionary advantage over creatures which cannot do this. So the Theory of Evolution cannot explain the evolution of the cornea followed by the optic nerve, but it can explain the evolution of the optic nerve followed by the cornea.
The second point is that there are very few things in nature which have only one potential function.
Go back to our mousetrap example. If we take away the catch and the trigger, what is left may not be a mousetrap, but it is a very effective paperclip. Take away the hammer and the spring, and what is left is neither a mousetrap nor a paperclip, but it can serve as a paperweight or a doorstop. In the meantime the hammer and the catch, detached from the mousetrap, can serve as a large hook, and a small hook, respectively. And so on.
In other words, a particular biological feature which we observe to be adapted to a particular purpose can, in the course of evolutionary history, have survived because it was adapted to a quite different purpose. The fact that it is now part of an irreducibly complex mechanism does not mean that it was always so. And proponents of evolution claim that, when "irreducibly complex" structures are examined, their component parts are found to be potentially adapted to purposes which do not depend on the irreducibly complex structure.
The second challenge mounted by Intelligent Design is that of "Specified Complexity".
Suppose I invite you to type 17 letters at random. You type "wochrleuodcurhtsl". This is a complex sequence of letters, but it is not specified; you could type any seventeen letters, and comply with my request. In other words, you can comply with my request by random letter selection.
But suppose I specify that you are to type the first seventeen letters of Advance, Australia Fair. This is no more complex than "wochrleuodcurhtsl", but it is specified; the only sequence of letters which will meet my requirement is "australiansalllet". The chances that you will type this by random letter selection are infinitesimally small.
ID proponents suggest that specified complexity analogous to "australiansalllet" can only arise in the natural world through intelligent intervention.
Proponents of evolution respond by saying that it is a mistake to assume that biological organisms evolve to match a specified complexity. Yes, sometimes complex organisms evolve, but they are not evolving to any specification. And, equally often, evolution destroys complex organisms. For example, if a species which has eyes begins to live underground, the eye becomes a useless and (in biological terms) expensive luxury. Over time evolution can cause the eye to atrophy, then to become vestigial, and finally to disappear altogether. Consequently evolution does not move in the direction of a specified complexity, or even of complexity. It moves in the direction of adaptation to the environment, which will sometimes favour complexity, and sometimes simplicity.
Let me stop here. I am not a scientist, and am frankly not qualified to say whether the observed evidence best supports the proponents of evolution, or the proponents of intelligent design. I can barely understand the arguments put forward on both sides and, even then, only some of the arguments. I certainly cannot say which arguments are correct, and which are not.
But, as discussed in my commentary last week, I do not look to science to support or "prove" religious faith, and I think it is a mistake to do this. As well as the scientific objections to Intelligent Design theory, there is also a philosophical objection, and that is what I would like to look at next week.
Peregrinus is a lawyer recently migrated to Australia from Ireland. He has a seemingly encyclopaedic knowledge of Catholic church history and the ability at short notice to put his finger on the facts that are needed in the many controversies that erupt on internet discussion forums.
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