In the physical world, when we observe various things that have been made, we know that there is a designer behind all of them. For example, we look at a watch; camera or computer and we realize that someone had to purpose, plan and build these marvellous machines.
If that is so, then what about the Universe in all of its complexities? If the camera has a human designer, is it not reasonable to think that the human eye (more complex than any camera) has a Divine Designer? If the computer has a human designer, is it not reasonable to infer that the human brain (more complex than the greatest of computers) has a Divine Designer?
If these things are not so, then we are left with a situation where there is an Intelligence that has created the Universe and humanity, but we know nothing of it for none of us has directly observed it. Or, we are left with the absurd conclusion that we are products of unintelligent matter that just happened to come together by unexplainable chance.
Imagine you are the presiding judge over a murder trial. Ballistic tests match perfectly with a gun found in the possession of the accused. The odds of another gun firing the bullet that killed the victim are let's say one in a billion.
The defendant claims that it is a sheer fluke that his gun happens to match the ballistics tests and that there must be another gun out there that is the real murder weapon. "After all," he says, "it is a possibility."
The defendant's fingerprints are found all over the victim's body. He claims there must be another person out there who happens to have astonishingly similar fingerprints. Again, it is possible.
There are also eyewitnesses who testify to seeing a man gunning down the victim who looks just like the defendant. The defendant claims there must be another person out there in this big world that looks just like him, and that man is the real murderer. After all, it is not impossible.
In the pragmatic world of decision-making, odds this high are called impossible. One needs to weigh the evidence and come to the most reasonable conclusion.
Does the universe have a Creator? Look at the design, look at the odds and look honestly within. Where does the more rational conclusion lie?
Probably the single most popular way of proving God's existence is to use the 'Design Argument', and point to (what proponents think is) design, order and purpose in the universe as evidence of it having been created by God. This view is found in Cicero and the ancient Greeks and was quite likely the oldest reason people had for believing in God. It's the reason for believing in God many ordinary religious people today find persuasive, though I personally think it's the weakest argument.
The Design Argument is a 'teleological' argument based on the evidence of design a lot of people see in the world around them, and as such has the possible strength of being based on empirical observation rather than the abstract reasoning found in arguments like the ontological , and, to a lesser extent, the cosmological one.
It states that we can see complex designs with a purpose, order, regularity and all sorts of other evidence in the world that suggests an intelligent, infinitely great designer who created it all: God. The famous framing of the argument by Bishop William Paley asks us to consider what we would think if we came across across a watch while walking across a desert. We could reasonably deduce, says Paley, that such a complex design adapted to the purpose of showing the time did not come about by chance, but was the result of intelligent design. Paley said that the universe is like a watch, and that it is clearly designed, even if we do not know its exact purpose. Paul Davies, a philosopher of religion, sums this up well by saying that if on the back of every rock we saw 'MADE BY GOD' printed in block capitals (perhaps with a list of instructions for what that rock should be used for?) it would be reasonable to assume from this evidence that there was a God.
The actual evidence is not quite so clear, but Paley and others have pointed to such things as the way the number of teats on animals equal the number of their young and the extremely complex design of the human eye that lets us see. All such things, they say, show such complex design, all for a purpose, that they can't just be the result of chance. They must come from a God who has planned the universe for humans. This is the anthropic principle, which points to the presence of food on the planet, the (fast-disappearing - thanks President Bush!) ozone layer and the exact values of scientific constants without which the earth would never have formed. Even evolution is included in this theory, as the perfect way for God to create us. The chain of coincidences needed for human life to emerge, they say, make it clear that it was no coincidence at all. There certainly seem to be a lot of things in the world which fit this idea of design.
Another form the argument often takes is to point to the order and regularity in the universe as evidence of design. Paley used the example of the uniform, perfect rotation of the planets, as did Thomas Aquinas in his fifth of five ways of proving God. Aquinas said that this regularity can only have come about at the behest of an intelligent being, as otherwise the fact that things obey uniform laws would just be the result of chance. Aquinas' original argument actually rested on a lack of knowledge of science, and the idea that the movement of the planets must be 'God's will' every single time rather than the result of natural laws, but the deeper question of just why these laws exist could still be asked. The regularity we see in the universe about us might be taken as evidence for God.
People also sometimes point to beauty in the universe as evidence of God's work. Appreciating beauty has no survival value and the theory of evolution might make you think we should just be looking for food and mating constantly. The fact that we can instead see beauty in all sorts of things in the universe, from human art to nature, suggests a designer God. This is quite a neat example of how such a conclusion would see the universe as a fundamentally good creation of God, with a clear purpose and God's footprints everywhere.
But is the universe really like this, when you look at it open-mindedly? One major criticism of the Design Argument would be to point to all the things that contradict it. If you're basing an argument on the evidence, you can't just ignore anything that doesn't fit in short, you first have to argue your way out of the problem of evil. This points to all the suffering in the world and asks how this fits in with a benevolent, omnipotent and omniscient God.
You can recognise that there is much left to be desired in the world even if you're an optimist. Hundreds of millions of people starve, even nowadays, because there is not enough food. Wars are waged; people die, and crimes are committed. Even if you seek to blame these things on 'free will' (which is dubious because there is a convincing case to be made for determinism, the idea that everything we do is going to happen in one specific way because our free choices are not random and have causes) you are still left with natural disasters. Tornados, floods and volcanoes, together with diseases and other suffering, could surely have been prevented by an omnipotent God. The world isn't bad, but is it the best one possible? I think not.
There are many other things in the world, which cast doubt on the idea that it is God's design. You might say that evolution is "the perfect way for God to create the human species", but why is this true? Surely God would just create us from scratch, as it says in Genesis, rather than wasting all that time, and all those unsuccessful animals, on our evolution. Likewise, if God created the world just for us, as the anthropic principle states, what are cockroaches doing here? Why is the centre of the earth a complex, turbulent mixture of molten lava and various minerals rather than just a stable lump of rock? Actually, as Hume pointed out, the universe bears a closer resemblance to something organic, like a plant, than it does to a neatly constructed watch (with a very clear purpose and no superfluous parts), and as we're trying to work out what created things like vegetables in the first place, it's useless to use that as the basis of an analogy.
All that may sound rather trivial, but the point is that all these things fit in much better with just a natural universe than with God's creation. You'd have thought if God, a being without a body, had created the universe, he would have made it a sort of spirit plane where we floated about, exchanging opinions about art and being righteous, without having to worry about all the bodily distractions.
You can even question the whole grounds of the analogy, as did the (18th century) philosopher David Hume. Hume was actually one of the first to formulate the argument, in his Dialogues Concerning Natural Religion, but he did so only to demolish it by pointing out the weakness of the analogy. If, like Paley, you compare the universe to a watch, which has a watchmaker, this analogy leads you to a very human God, as that's all the analogy is based on. He says (through Philo, the sceptical character in the Dialogues) that there could be many Gods cooperating, more like superhuman Greek Gods than the traditional Christian God, who are male and female, have children or die. Quite likely, they are quite imperfect, and this universe is just the work of a trainee God who went on to better things the evidence, which is all we have to go on, would certainly seem to fit with that, as in it's current state the universe resembles more a child labour-produced Chinese watch with several LEDs missing than a Swatch.
The deeper point here, which Hume goes on to develop in his other works, notably An Enquiry Concerning Human Understanding, is that if the Design Argument is based on the evidence, then it's very hard to abstract up to the infinite, all-loving God Christianity proposes. If you can see that a peanut on a pair of scales is outweighed, all you can conclude is that there is something heavier than a peanut on the other side. You can't deduce the presence of an elephant. If you treat the Design Argument as a truly scientific, empirical approach, there's not much you can prove above the world, and you certainly can't arrive at something transcendental. There's 'no evidence in the world' (literally) to suggest that such a thing exists. Even if you conclude that there's a designer, there's no reason to think that he's the God of traditional theism. Hume is saying that we can never arrive at the idea of an absolutely perfect, transcendental God from the material universe. As Philo puts it, we should withhold judgement until someone proves such a God.
As for the fact that the universe is fairly regular and ordered, again evidence could be produced to counter this. There is certainly not perfect order in the world, with, for example, the universe expanding until eventually there's nothing left. But what order and design there is is still impressive, and you might say that it is fantastically unlikely that it came about by chance, even if a Christian God is not proven. The Epicurean hypothesis of ancient philosophy comes up with a convincing answer to this, saying that even in a random, chaotic universe order would still develop. There is such a thing as an ordered, constant, self-perpetuating state of affairs (we are living in one) and once such a state came about by chance (the current order took several billion billion years of prehistory in the universe) it would tend to stay for a long time, otherwise it would not be order.
Of course, the most famous natural explanation for apparent design in the world is evolution. This, in case you were taught science in Kansas, is the theory developed by Charles Darwin and Alfred Russell Wallace which explains apparent design in humans and (other) animals in terms of natural selection whereby those animals who develop the best features through random mutation of the species survive to pass on those genes, while those who don't die out. This explains why we don't see any completely undesigned animals: they've all died out.
Evolution, to use Richard Dawkins' book title, acts like a kind of 'Blind Watchmaker' it comes up with things like the number of teats on animals matching the number of their young and the intricate design of our eyes, which at first look like they might have been designed. Some people find it hard to believe the theory of evolution, but bear in mind that it has had millions of years to come up with humans, working in small steps. It's hard to conceive this lengthy process, but that's just what Dawkins in The Selfish Gene calls an argument to personal incredulity.
There is another type of order in the universe, that the Design argument says must be result of God, as it could not have come about by chance. This is the order we see in the laws of nature themselves. If you explain the world in terms of scientific laws, then you still have to answer the question of where these laws came from. This is undeniably a perplexing question. Saying "I don't know all we can say is that they're just there" doesn't sound very satisfactory, but it may be all we can do. Saying God is the cause of all these fundamental laws doesn't really answer the question, as you can then ask what caused God and why he's there. Saying God created the universe just places the buck of explanation onto saying why God exists, and just what sort of thing he is.
After all, an infinitely perfect, timeless, spaceless, transcendent being who created the universe and all the natural laws is a pretty hard idea to get your head around, and it's not even certain such a thing could really exist. People often use Occam's razor (the principle that you should pick the simplest explanation to satisfy the evidence available) to try and show that we should accept the fact that God designed the universe rather than saying it's a huge trail of coincidences, but God is pretty complex and unbelievable himself. And that's without the fact that if you want to use the Design Argument you have to supply a reason for the fact that this isn't the best possible world and, when you get past the desire to see purpose and design thoughout it (which leads to some pretty dodgy excuses for people like Britain's Royal Family), it doesn't really seem to be the kind of world God would create.
