The classic example is as in “[wiki]The Blind Watchmaker[/wiki]”: a man finds a watch in a field and concludes that it is a manufactured article rather than a natural object. From this he draws the erroneous conclusion that, as a consequence, all
objects that are complex must be the product of a manufacturing Being whose powers and invisible celestial factory allow him to make such things because, surely, they could not have arisen naturally…
The man thinks further and considers the universe,
“How wonderful that I am here! If the slightest thing had been different, I would not exist, surely the Universe was designed around my needs!”
Well, not only is that a huge piece of arrogance to think that the entire universe is here only to support man, but the reasonable person will see that the conclusion is wrong but may be unsure as to why it is wrong.
In the case of the watch, it was clearly designed but, just because one
complex thing is designed, it cannot mean that all
complex things are designed.
Imagine an Alien arrives on earth. He has pictures of the creatures of earth. The first dog he sees has only three legs.
Q: Does he think, “This dog has only three legs, therefore the picture I have must be wrong and all dogs must have only three legs.”?
A: No, he does not. He knows that he needs to see more dogs and then reach the correct conclusion that the dog he first saw did not establish a rule. This is “testing the hypothesis.”
So we must ask ourselves why anyone should think that a watch found in a field gives the clue to God’s existence, and thus His Creation of the Universe and all that is in it.
Douglas Adams (of “The Hitchhiker’s Guide to the Galaxy” fame) explained the error thus http://en.wikiquote.org/wiki/Douglas_Adams
Imagine a puddle waking up one morning and thinking, "This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!" This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for.
We all know that at some point in the future the Universe will come to an end and at some other point, considerably in advance from that but still not immediately pressing, the sun will explode. We feel there's plenty of time to worry about that, but on the other hand that's a very dangerous thing to say.
Speech at Digital Biota 2, Cambridge, UK, (1998)
There is an even simpler way of looking at the idea of so-called intelligent design:A man is staring at a cat. Eventually, he turns to his wife and says,
“Consider that cat. It is truly wonderful.”
The wife looks at the cat for a while, but the cat seems quite ordinary. She then says,
“In what way is it wonderful?”
“Well is it not obvious? Look at the cat; look at its eyes!”
The wife does so but still does not understand, “What about the cat and its eyes?”
“Well it is amazing, there are holes in the cats fur and skin exactly where its eyes are! One mistake and the cat would have two empty holes and its eyes would be under its skin.”
Of course, the wife is not fooled. People who accept Intelligent Design are the victims of the misuse of logic. Intelligent Design is nothing more than a joke, a trick, a deception. The victim is led one way and, whilst his intelligence is deceived, a false conclusion is drawn.
Here is an old proof that misuses logic to ‘prove’ that 2 = 11. Let a and b be equal (but not zero)
2. Multiply through by a
a2 = ab
3. Subtract b2
a2 -b2 = ab - b2
4. Factor both sides
(a-b)(a+b) = b(a - b)
5. Divide out by (a-b)
a+ b = b
6. Observing that a=b
b+b = b
7. Combine like terms on the left
2b = b
8. Divide by the non-zero b
(From this I can say that I and the pope are two different people but, as 2=1, I am the pope.)
If you do not think about it, something that is obviously false, will appear to be true.
Can we now never speak of “Intelligent Design”again? It makes people look foolish if they believe it.