According to a Yahoo News article, Dr. Michael Behe is testifying for the defense in the Dover, PA school curriculum case today.
Behe is the author of Darwin's Black Box, a book in which he tries to sell readers on the idea that some biological structures are so "irreducibly complex" that they couldn't have evolved by chance alone, so there must have been a designer guiding the process. ID advocates always trot him out when their attempts to push pseudoscience into high school science classrooms go to trial.
So why do I call him Dr. Ego? Because he assumes that if he can't personally envision a reduced version a particular biological structure, then it's impossible for such a reduced structure to exist. In other words, nature is limited to what Michael Behe's imagination will allow it to do.
A simple example is one of his favorite "irreducibly complex" structures, the bacterial flagellum, because it would no longer function if you removed one of the proteins that makes it work. The problem, of course, is that just because a given modern bacteria requires a particular protein in order to swim doesn't mean that its ancestors required that protein.
Dr. Behe can't (or won't) see how the bacterial flagellum could have evolved, but plenty of other scientists have published articles on just that subject. In a nutshell, there's nothing "irreducibly complex" about bacterial flagella in general, although it would be easy enough to break a particular modern example.
Dr. Behe's "irreducible complexity" argument fails on two points of logic...
First, it's just a standard "argument from incredulity", in which he attributes a phenomenon that he can't understand to an "intelligent designer" who must be smarter than he is. What he lacks is evidence of any kind. Saying "this looks too complicated to me" does not constitute evidence, and a theory needs evidence in order to have credibility.
Second, it's also a "false dilemma" argument, in which any problem or weakness in Theory A (in this case, the Theory of Evolution) is taken to be a confirmation of Theory B (in this case, Incompetent Design). The problem, of course, is that finding a weakness in the evidence for Theory A does not actually constitute evidence for Theory B. In other words, even if the Theory of Evolution doesn't (yet) fully explain the development of a particular biological structure, there is no reason to jump to the conclusion that it was designed by aliens, God, or pan-dimensional beings disguised as mice.
I find his choice of t-shirts for this photo particularly amusing, since the ID explanation of the complexity of life is basically "a wizard did it".