I believe a teleological system is just another name for a complex system.
For instance, a watch is a very complex system.
The Teleological Argument is an argument for the existence of God. This argument suggests that after viewing a watch, that one must think that the complex system could not have been formed by evolution, but a creator; considering the complex system of the watch.
The therory uses the following assumptons
1.Human artifacts are products of intelligent design; they have a purpose.
2.The universe resembles these human artifacts.
3.Therefore: It is probable that the universe is a product of intelligent design, and has a purpose.
4.However, the universe is vastly more complex and gigantic than a human artifact is.
5.Therefore: There is probably a powerful and vastly intelligent designer who created the universe.