A long post at kuro5hin takes apart the most cherished pieces of pseudoscience used to explain Intelligent Design.
A third argument for Intelligent Design is the so-called “Fined-Tuned Universe” argument. If certain physical constants were different, life would not exist, it is argued. For example:
If the strong nuclear force were to have been as little as 2% stronger (relative to the other forces), all hydrogen would have been converted into helium. If it were 5% weaker, no helium at all would have formed and there would be nothing but hydrogen. If the weak nuclear force were a little stronger, supernovas could not occur, and heavy elements could not have formed. If it were slightly weaker, only helium might have formed. If the electromagnetic forces were stronger, all stars would be red dwarfs, and there would be no planets. If it were a little weaker, all stars would be very hot and short-lived. If the electron charge were ever so slightly different, there would be no chemistry as we know it. Carbon (12C) only just managed to form in the primal nucleosynthesis. And so on.” (McMullin 378)
If one were to go fishing and catch 50 fish, all of which were more than ten inches long, one might reasonably make the hypothesis that all of the fish in the lake are more than ten inches long. Someone else might make another hypothesis, that only half the fish in the lake are more than ten inches long. It seems obvious that the first hypothesis is more likely. But what if, upon closer examination, it becomes clear that the net being used to catch the fish had holes that prevented it from catching fish smaller than ten inches, and that the fisherman left it in the water until it had caught 50 fish? This new information must now be incorporated into the hypothesis, causing both to have a likelihood of one, thus preventing one from being more likely than the other.
This situation can be directly applied to the fine-tuned universe argument. It may seem on the surface that the likelihood of a universe in which all of the constants are right for life given an intelligent designer is much higher than the likelihood that the constants are right given random chance. When we add in the fact that we are here to observe the universe, however, we find that the likelihood of a fine-tuned universe is one either way. If we are here we must be in a universe which is tuned to our existence. The likelihood of a fine-tuned universe given that there is an intelligent designer and that we live in a fine tuned universe is equal to the likelihood that we live in a fined tuned universe given that it was created by random chance and that we live in a fine-tuned universe.
Pr(Fine-Tuned Universe | Intelligent Design & Fine-Tuned Universe) = Pr(Fine-Tuned Universe | Chance & Fine-Tuned Universe) = 1