Here is a hypothesis which can be refuted: "There does not exist any naturally occurring genotype whose existence is not explicable by a process of natural selection in the context of non-directed mutation." Let's call that the DarwinWins hypothesis.

The DarwinWins hypothesis is logically equivalent to the statement that all naturally occurring genotypes are explicable by a process of natural selection in the context of non-directed mutation. It's useful, though, to state it as I did the first place... the "there does not exist" form, because:

If the DarwinWins hypothesis is true, then the hypothesis of intelligent design is false. This is a problem for intelligent design advocates because so many genotypes have been reasonably explained as the result of natural selection and non-directed mutation. If you want to prove that intelligent design even has a chance of being true, then you must prove the negation of DarwinWins. That negation is:

There exists a feature, Y, inexplicable by natural selection and non-directed mutation. You could call that hypothesis, DarwinLoses. Proving that DarwinLoses is true would not prove intelligent design true, but it would prove that DarwinWins is false. And intelligent design can only possibly be true if DarwinWins is false. So if you want to argue for intelligent design, you must provide some proof that DarwinLoses is true.

In other words, you must come up with an observation of a single, naturally occurring genotype, Y, which can not be accounted for by natural selection and non-directed mutation. That would be your "black swan" ( http://en.wikipedia.org/wiki/Falsifiability ) that disproves DarwinWins.

In your comments on that other blog, you offered one suggestion: the eyes of higher animals. Unfortunately for your case, the complexity of the eye is hardly a surprising outcome in the DarwinWins case. (E.g., c.f. http://www.pbs.org/wgbh/evolution/change/grand/ )

Now, it is true that DarwinWins is as impossible to prove with absolute certainty as hypotheses such as "No elves with magical powers exist." However, the NoElves hypothesis is a very effective and simple theory of why no direct or indirect evidence for magical elves has ever been observed in a controlled experiment. We would say that the YesElves counter-hypothesis lacks any evidence whatsoever to support it. Elf believers might be upset and say "But you haven't yet proved with absolute certainty that there are no magical elves!" and they would be correct - but they are being unscientific when they say "I'm pretty sure there are those elves!"

Similarly, intelligent design fans, who must embrace DarwinLoses if they have even a chance to be correct, have yet to show one single piece of evidence against DarwinWins. Meanwhile, lots of evidence in support of DarwinWins has been collected, again, and again, and again.

We don't teach the YesElves hypothesis in biology or physics class as an open-minded alternative to NoElves. We don't regard YesElves as a viable scientific theory. I.D. (DarwinLoses) has about as much logical and empirical support as YesElves... it is hard to take I.D., in the form you are arguing for it, any more seriously than YesElves.