We often hear that ID is an argument from incredulity. At this point I would tend to agree. That said, arguments from incredulity aren’t necessarily wrong but in fact are rather reliable and employed constantly and consistently by everyone every day.
Let’s take the example that Granville Sewell offered in his most recent post here. He described Schrodinger’s equation and showed us that it’s theoretically possible for a pitched baseball to stop and hover in mid-air. A commenter who appeared to have a reasonable understanding of Schrodinger’s equation at first protested then ended up agreeing that it’s possible but the odds against it are long and for all practical purposes incalculable. They went on to agree that the quantum uncertainty is tractible in the analysis of a single electron orbiting a single proton (a hydrogen atom) but that the math is intractible for a pitched baseball because such a large number of particles are involved.
So how do we “know” that a pitched baseball won’t stop and hover in mid-air? Incredulity is how. We can’t precisely calculate the odds against it due to the system being so complex but we know it is (literally) incredibly improbable. It’s the same thing with ID. Although we can’t calculate the odds precisely we do know enough to see that self-organization of atoms into structures as complex as the machinery found in living cells is incredibly improbable. We couple this with the sure knowledge that intelligent agency routinely produces organizations of matter that, absent the intelligent agent’s intervention, are incredibly unlikely.
Here’s a good example. In principle it is possible for two cows to mate and give birth to a chimpanzee. The reason we don’t ever expect to see such a thing is we know (now) that the genetic differences between a cow and a chimp are so complex and specified that the odds against it actually happening in a single generation are nearly impossible. We can’t calculate the odds precisely but we know it is incredibly improbable. The argument that two cows won’t mate and produce a chimpanzee is an argument from incredulity.
Likewise, is it possible that a bacteria can, through RM+NS, change into a baboon over a billion years and trillions of generations? Sure it’s possible but when you actually get down to assessing the sequence of changes that must have occurred, analyzing the probability in a finite number of years and a finite number of generations, using everything we know about the mutation and selection mechanism, it quickly becomes an incredible proposition. It grows more incredible every day as new knowledge of the underlying physical mechanics is discovered.
So the next time someone tells you that ID is an argument from incredulity you can simply respond by saying “Yeah, so what? Arguments from incredulity are common and quite reliable in all aspects of life from the physics of baseball to the physics of biology.”