Paley wrote of the watchmaker some 300 odd years ago, the book that would lay the foundation of the Intelligent Design theorem – today the only theory that even attempts to challenge evolution through natural selection as an explanation for biodiversity. In the 1980's Ricard Dawkins wrote an answer to ID called "The blind watchmaker", indicating how random the process of nature is – how some cells can start of converting light energy into motive energy, become light sensitive cells and then get better and better at it until you get a human eye, all without any plan – simply the pressures of survival consistently favoring those with the edge right now.
And evolution is chaotic (in the mathematical sense – as in chaos theory) because the environment creatures compete in is always changing and their responses change it for other creatures. Bringing Dawkins to declare that evolution is a blind watchmaker, jamming parts together out of whatever is handy and whichever watches do something useful survive.
In the 1990's an answering book "how blind is the watchmaker" challenged the idea that evolution is random – from an Intelligent Design perspective, attempting to state that there must be perpetual influence because random change simply could not create such organisation.
I side with evolution – as it stands today (which is a massively refined theory from the days of Darwin's first beginnings with it), but Intelligent Design does claim to be science, it does (mostly) obey the scientific method. Most scientists laugh at it because it's theist views are just a little too obvious and the scientific arguments made are fully debunked by the evolution theory as it stands – and that has a lot of evidence going for it while apparently the only real evidence for ID is it's proponents desperate desire to require God's continuous and permanent intervention in the cells of every single creature on the planet. They may not wish to say it, and asking that their scientific arguments and research be judged as science is fair enough – but there is a point after that where it goes a little wrong. Scientists do not try to prove their theories. Scientist take observational data and attempt to explain it with a hypothesis. Then they and other scientists do everything they can to try and prove that hypothesis false. Consistent failure to do so is what makes a theory trustworthy (not truth – that doesn't exist) but trustworthy – especially if you keep up on it knowing there will be further refinement as and when new data comes to light.
Intelligent Design proponents are hunting evidence in favor of their theory – instead of doing the scientifically proper thing which is to hunt evidence against it, this is at least part of why evolutionary scientists have such an easy time debunking their arguments every time. Because the evidence against the arguments are consistently easy to find – but the I.D. proponents didn't go look for it, didn't refine their own arguments before presenting them by trying to falsify them – and thus other scientists do it with such ease as to make I.D. look absolutely amateurish.
But I want to add the next step to the chain and ask. How intelligent is the designer ? This is an important question because it looks at one of the fundamental points of I.D. that life is designed, planned and organized with great and exceptional intelligence – either upfront or through constant intervention, I think that argument itself is intensely egotistical – and what's worse is at odds with the primary theist source for I.D. – Christian Creationism !
The fundamental argument in favor of I.D. is how perfect life is developed, how perfectly it fits together. How perfectly our bodies are designed. But that is just plain wrong. We are very far from perfect, and so is everything else. We are at best a work in progress. Christian Creationism at least offers an explanation for that – we are imperfect, both biologically and spiritually because of original sin. I.D. however wants to be taken seriously as science – ergo it's arguments cannot rely on holy books but must be built on evidence.
If the primary evidence they put forward for design is that such perfection and organisation requires an intelligent designer – then it all falls apart in the absence of perfection. It may be religiously sensible – but it's not science anymore. Unless they can prove a massive past regression in body designs of all living things… then they end up not with an Intelligent Designer but an incredibly stupid one. That is not a line of argument they would push of course, and their theist support would rapidly evaporate if they did – but it's the conclusion their own argument leads to when we consider all the facts. Here I am not talking about diseases and such – those are our interaction with other living organisms and ID would say they are also designed and it all fits. I am talking about design flaws easily visible in the bodies of all creatures – including ourselves, I'll use human bodies as an example though.
Lets just take a few simple examples:
1) The most powerfully evolved (or then designed) part of the human body is our brains – the source of our own intelligence, but our brains get psychotic imbalances all too regularly, they clearly aren't designed to be very resilient even to bad influences from within themselves. Our computers may not be as fancy – but they are a damn site more reliable. They are a lot harder to fool too. Even our memories are imperfect and often flawed (in extreme cases such as false memory syndrome we can have entire memories that were generated by our brains not only without any real events related to them – but to mask the events that actually happened at those times).
2) The appendix – a body part today which is more of a burden than a boon. It's of so little use to us that it's routinely removed through surgery with no known negative effects whatsoever – but untreated the infections which most of us will get at least once in it, are fatal. Why would an intelligent designer (especially an interventionist one) leave it in us in the first place then ? Evolution has an easy answer – it's not enough of a survival issue to affect breeding and thus doesn't get evolved out (at least, not fast), ID just ignores it.
3) One of the number one causes of death in the world, especially among children, is choking. Why do we choke ? Because the passage way our food takes to get into our digestive tract crosses over our airway. A complex set of valves try to guide it all past without letting it in there but we know this valve system is less than perfectly reliable. It wold have been much more survival beneficial to have practically any other layout of that piping. Many other creatures do have different layouts. None of them are land vertebrates however because this piece of piping belonged to that early fish ancestor who first crawled onto the beaches and gave birth to all land animals – they had it, and everything since then inherited it. We know this because we have their fossils. All their descendents kept that flaw despite being frequently fatal right down to us. Evolution says – it wouldn't evolve away because initially there was nothing else on land to compete with and later their descendents (having been around there longer) were superior in so many other ways it quickly become a major dominant design mostly at competition with itself – and since the problem affected everybody equally despite being a flaw it wasn't big enough to be a sufficiently major determining factor in breeding to ever evolve away. I wrote about this one in by far the most detail -in part because I happen to have the most information on the topic in my general knowledge store and *can* say more about it, but also because it's probably the best example of all. No engineer who has to move two things in pipes that should never mix will ever cross the pipes and rely on taps and valves to close one off when the other is flowing ! Hell no plumber would do that … okay maybe some plumbers would but any other plumber would call them idiots.
Yet I.D. wants us to believe an intelligent designer burdened almost every creature on the planet with these flaws ? They best answer I think they could possibly come up with was "it was on purpose – to help control population rates"… well we already have according to them a designed in flaw to do that, it's called "aging". How many do we need ? Evolution would develop multiple ways to control population growth because it's random and anything that helps prevent overpopulation increases survival rates – it would have numerous partial solutions that add up. I would think an intelligent designer would be quite happy to find one – that there is no defense against and use it. Ageing is no constant – different species have different rates of aging, so obviously I.D. would say this is tweaked to their needs – with such a near perfect mechanism – why do you need a choke-hazard built right in then ?
The biggest flaw I see in Intelligent Design is this -if bodies are designed, it was not done very intelligently at all… do you really want to rest your faith on a theory that makes your Deity an idiot? Perhaps all those theists in Europe who long since decided to say "Evolution without direct intervention is gods chosen method" to say that not HAVING to manually intervene proves his greatness more than such interventions would (and every computer programmer would agree) and find God in their hearts without having to try and do war against the evidence of nature have a point after all ?
Do you really need to control people so badly that you tell them they have free will on the one hand but God is busy messing with the very cells of their bodies every single moment on the other hand ? Aren't those two concepts mutually exclusive ? Quite frankly – evolution is science that does a lot less harm to true faith than I.D. does, I.D. tries to scientifically prove a theory built on a theist ideal – what's worse the ideal of a theism that specifically warns you that you will not be able to prove it, that has entire passages in it's holy book declaring the futility of seeking evidence as the very reason why faith in it has virtue.
That ideal – noble as it is in church, is not compatible with science. So do science in the science lab, religion in the church. When it comes to mundane matters of operation – trust the science. Science can tell us how we got here (or at least how we PROBABLY got here – there are currently a few alternative theories to the big bang that are solid science with as much going for it and choosing one definitively again will take some time while we gather more data), but it cannot tell you WHY we got here. String theory tries but just leaves an even bigger why… WHY string theory then ?
Religion does answer "why". If you're a believer – take all the comfort in that "why" that you want to – secure in the knowledge that science cannot answer it or disprove it, will not try to, and doesn't care because it isn't something science can affect, your heart is as valuable a measurement tool for it's worth as anything else so you may as well trust it. If you're an atheist well you can take comfort in knowing that none of those answers to "why" has any proof there is no solid reason except personal comfort for the believers to pick one over the other – so you don't need to feel any obligation to pick one at all.
Voila, we can all get along… In practice too many theists (bad ones really but no less influential for that) find that picking fights with others (other theisms and science alike) is far too efficient a source of economic and political power to ever accept such simple rationality.
So they will throw their weight behind dead end theories like I.D. as long as it suits them… when ultimately I.D. is down to just D and the D is looking less and less possible, they will be ready to pick a fight with somebody else and they probably wouldn't have finished that fight with they gays yet so … well you get the point.
EIther way, if you're a rational thinker who likes getting along with people, whether you're a believer or not… recognize I.D for what it is, a dead-end last-ditch attempt to challenge the evolution that happens in nature with something theists and scientific and it's not going to work for all the reasons I already gave. Acceptance and tolerance actually works better than trying to argue against the guys with the evidence.