The observed fact is that every species, and every organ that has ever been looked at withing every species, is good at what it does. The wings of birds, bees and bats are good at flying. Eyes are good at seeing. Leaves are good at photosynthesizing. We live on a planet where we are surrounded by perhaps ten million species, each one of which independently displays a powerful illusion of design. Each species is well fitted to its particular way of life.What is immediately striking is Dawkins's unselfconscious appeal to final causes; to say that every organ is "good at what it does" implies that there is in fact something that can be identified as what an organ "does", and its performance can be measured against that ideal. Now of course Dawkins would deny that there really is any such thing as final causes, and that this paragraph can be cashed out in materialistic terms. But it is interesting that in making a point about an illusion (the illusion of design), Dawkins makes it in terms of something that is, for him, just as much an illusion - the illusion of final causes. So it is the illusion of final causes that gives rise to the powerful illusion of design. I wonder what is the cause of the illusion of final causes?
More to the point, our "particular way of life" is the way of life of the rational animal. We are possessed of an organ, the brain, and "what it does" is know the world. According to Dawkins, every organ is good at what it does, so it must be that the brain is good at knowing the world. Yet the theme of The God Delusion is that most people's brains, for most of the time, have been grossly mistaken about elementary facts concerning the world; facts like the non-existence of God, the illusion of final causes and design and, recently, the reality of evolution. It's only because we have lately (in terms of human history) stumbled on the methods of science that we have been rescued from illusion and falsehood at all. The point can be put simply: If man were like other animals and "well fitted" to our way of life, there would be no need for The God Delusion.
Materialists like Dawkins want to claim that man is not different in kind than other animals, but there is simply no denying that we are. Some people say we are made in the image of God, and this makes us different in kind. Dawkins says this is an illusion, but in doing so he only creates a different manner in which man is unique: He is the creature not well-fitted to his way of life.