The teleological argument for the existence of God (the argument from design) postulates that the design of the world is so unbelievably complex that it must have been the creation of some sort of intelligent designer. If you were to paint a masterpiece and tell someone that the painting was created by randomly throwing paint at a canvas, that person would think that you are either a liar or a raving lunatic. Says the theist: the world is so much more complex then a simple painting therefore only a liar or a lunatic would ever suggest that it came to be through random forces of nature.
There is a flip side to this argument that needs to be acknowledged. For this argument from painting also offers us a standard from which to judge randomly created designs. If I were to randomly throw different colors of paint at a canvas I can create some unbelievably complex designs. So complex that it would be difficult to reproduce those same exact designs even if one set out to consciously copy each and every splotch of paint on a different canvas. Furthermore, with just a little push of the imagination one can often see pictures in the splotches of paint that are quite detailed. When I was younger I used to play a game with myself in which I would try to make out pictures from the cracks on the walls and ceiling. The pictures that I saw were far better drawn then anything that I ever could draw on my own. We must admit that random splotches of paint and cracks in the ceiling are in fact better artists then many people.
If we look at the world we must admit to the existence of complex objects randomly created by nature. Even the most ardent creationist would admit that there is no intelligent design in the placement of every peak, valley and rock in the Rocky Mountains. The Rocky Mountains are in the specific shape they are in due to random forces of nature such as wind, volcanoes and the shifting of geological plates. Despite the fact that the Rocky Mountains are the creation of random forces of nature, it would not be possible for human beings to recreate the Rocky Mountains down to each and every pebble. Clearly random forces of nature are far more capable designers then even people.
When we look at the world, what sort of design are we seeing? Is it the design of the Mona Lisa or is it the design of random splotches of paint thrown against a canvas?