According to William Dembski, there are three ways a particular phenomenon can have occurred.
The numbers that come up when you roll the dice. The arrangement of letters that occur when you spill a bowl of scrabble letters out on the floor. The features of a thing produced by chance are irregularity or non-patterned result. So this fall if I walk outside and my driveway is covered in leaves, I would never suspect that someone had come over and carefully placed each leaf in its position on my driveway.
The ripples in the sand on the beach. The angular shape of crystals. The perfect roundness of a bubble floating in the air. The features of a thing produced by necessity i.e. by some law of physics or chemistry are regularity and patterns. So when I see a whirlpool in the water of my bathtub as it drains, I know that there are the laws of physics at work. The perfect funnel shape is a result of the vortex of spinning water.
A watch, a car, a portrait, a choral symphony, a poem, a blog post are all examples of design. When something is obviously designed and made, it has complexity and is not necessarily regular. The complexity that results from design is not the kind of complexity that results from chance. A design is specific. Specified complexity is the hallmark of design. So when I see a completed game of scrabble, I know that those letters did not simply fall into their arrangement because they all spell words very precisely (the opponent made sure of that!).
This seems so obvious that it is odd that anyone would argue with it. But argue they do. Now, the above description of the design inference is not yet science. To be science, this idea much be measurable and quantifiable. And it must be falsifiable and repeatable. To this end, Dembski and his colleagues have gone much further in their attempt to establish the design inference as science. You can see more of his work at http://www.designinference.com/.
Anyway, why would anyone argue with such research? Because the motive for undertaking it was to give an honest critique of Darwinian Natural Selection as the explanation of all the variety of life we see. There are a number of scientists and physicians who seriously question Darwin. They have said:
"We are skeptical of claims for the ability of random mutation and natural selection to account for the complexity of life. Careful examination of the evidence for Darwinian theory should be encouraged."
These honest scientists and physicians are treated with disdain by those who are committed to atheistic materialism. There commitment is so deep that they will not tolerate any investigation or examination of contrary ideas or evidence. Talk about intolerance!