When it comes to explaining Intelligent Design Theory in simple terms, two men stand out in setting forth good example's of plain human logic. Many can explain something with complex scientific terms, however simple logic cannot be beat for bringing one to a clear understanding of an issue.
Intelligent Design Theory is not new thinking, it has been around for a long time in countering the Theory of Evolution. One of the first to bring it into the thought process and did a pretty good job of explaining his idea, was Mr. William Paley. In 1802 he published his Natural Theology. Toward the beginning of the book is the following example:
"Someone crossing a heath and finding a stone could reasonably attribute it's presence to purposeless natural causes. Yet upon finding a watch and discovering that it's parts were put together for a purpose, one could conclude that the watch had been designed."
By analogy, Paley argued, one could also conclude that living things are designed.
In the later years of Paley's life he found himself set upon by many who supported Darwin's theory of Natural Selection and evolution. Paley's error was not in his very good analogy, but rather, he got carried away after making a good point and then went on and on in making other examples some of which were considered simple and silly. He is rarely mentioned by philosophers or scientists anymore and is placed as just another loser in science's struggle to explain the world. He did make a worthy contribution however.
(CHECK OUT THIS VIDEO CLIP WHICH EXPLAINS THE IDEA NICELY.)
The second individual who is worthy of mention in setting forth a clear and logical example for us in understanding the idea behind Intelligent Design and Irreducible Complexity is Mr. Michael J. Behe, Ph.D.
Mr. Behe set forth the example of the simple "mouse trap" that we are all very familiar with. We need not have an illustration for we all know the components they are made with. Here, we will go to Mr. Behe's explanation:
"Let's consider an everyday example of irreducible complexity: the humble mousetrap. The mousetraps that my family uses consist of a number of parts. There are: a flat wooden platform to act as a base; a metal hammer, which does the actual job of crushing the little mouse; a spring with extended ends to press against the platform and the hammer when the trap is charged; a sensitive catch that releases when slight pressure is applied; and a metal bar that connects to the catch and holds the hammer back when the trap is charged.
Now you can't catch a mouse with just a platform, add a spring and catch a few more mice, add a holding bar and catch a few more. All the pieces of the mousetrap have to be in place before you catch any mice. Therefore, the mousetrap is irreducibly complex.
An irreducibly complex system cannot be produced directly by numerous successive, slight modifications of a precursor system, because any precursor to an irreducibly complex system that is missing a part is by definition nonfunctional. An irreducibly complex biological system, if there is such a thing, would be a powerful challenge to Darwinian evolution. Since natural selection can only choose systems that are already working, then if a biological system cannot be produced gradually, it would have to arise as an integrated unit for natural selection to have anything to act on."