“When is it reasonable to conclude, in the absence of firsthand knowledge or eyewitness accounts, that something has been designed? For discrete physical systems—if there is not a gradual route to their production—design is evident when a number of separate, interacting components are ordered in such a way as to accomplish a function beyond the individual components. The greater the specificity of the interacting components required to produce the function, the greater is our confidence in the conclusion of design…

[S]uppose you are walking with a friend in the woods. All of a sudden your friend is pulled high in the air and left dangling by his foot from a vine attached to a tree branch. After cutting him down you reconstruct the trap. You see that the vine was wrapped around the tree branch, and the end pulled tightly down to the ground. It was securely anchored to the ground by a forked branch. The branch was attached to another vine—hidden by leaves—so that, when the trigger-vine was disturbed, it would pull down the forked stick, releasing the spring-vine. The end of the vine formed a loop with a slipknot to grab an appendage and snap it up into the air. Even though the trap was made completely of natural materials you would quickly conclude that it was the product of intelligent design…

In order to reach a conclusion of design for something that is not an artificial object (for example, an arrangement of vines and sticks in the woods to make a trap), or to reach a conclusion of design for a system composed of a number of artificial objects, there must be an identifiable function of the system… the function of the system we must look at is the one that requires the greatest amount of the system’s internal complexity. We can then judge how well the parts fit the function.” – Excerpts from Darwin’s Black Box by Dr. Michael Behe