William Dembski, director of the Center for Interdisciplinary Studies at Princeton University, holds a Ph.D. in mathematics and another in philosophy. Dembski argues that intelligent design, far from being a strange and exotic notion, is something we encounter and recognize every day. Dembski points to entire industries whose very existence depends on being able to distinguish accident from design: including insurance fraud investigation, the criminal justice system, cryptography, patent and copyright investigation, and many others. We do not call these industries “unscientific” simply because they look for evidence of design. Indeed, whole scientific disciplines could not exist without the notion of intelligent design. Anthropology and archaeology are two such disciplines.

“How could we ever distinguish a random piece of stone from an arrowhead except by appealing to the purposes of primitive artisans?” says Dembski. According to Dembski, we recognize design in events or objects that are too improbable to happen by chance. Stones don't turn into arrowheads by natural erosion. Writing doesn't appear in sand by the action of waves. A fair coin doesn't come up heads a hundred times in a row. These things only happen when intelligence is allowed to determine the outcome.

On the other hand, there's more to design than low probabilities. For instance, if you toss a coin a hundred times, any string of results will be extremely improbable. (If you don't believe that, try getting exactly the same string of results twice.) Still, if someone told us they flipped a penny a hundred times and got  normal results, we'd probably believe them:

On the other hand, says Dembski, “Suppose this person comes to you and says, 'Would you believe it? I just flipped this penny 100 times, and it came up heads each time.' You would be ill-advised to believe that this person is telling the truth.”

So what's the difference between the first set of results and the second? If you look at just the probabilities, there's no difference at all. Yet the second sequence makes us suspicious, while the first one does not. We would also be suspicious if the tosses came up all tails, or if the first 50 tosses were heads and the next 50 were tails or if the same sequence came up two times in a row.

Thus, it's not just the low probability that makes us raise our eyebrows. It's also the kind of sequence we get.

“Our coin-flipping friend who claims to have flipped 100 heads in a row is in the same boat as a lottery manager whose relatives all win the jackpot or an election commissioner whose own political party repeatedly gets the first ballot line,” says Dembski. “In each instance public opinion rightly draws a design inference and regards them guilty of fraud."

If detectives can use this kind of thinking to spot election and lottery fraud, if archaeologists can use it to spot arrowheads, why can't biologists use it to look for design in the living world?”

Currently, Dembski, Meyer, and Paul Nelson, a biologist and Ph.D. candidate in philosophy at the University of Chicago, are writing a book that details precise scientific criteria for recognizing design, and applies them to biological systems.