The existence of God is a perfectly respectable topic for a philosophy class. In fact, I'd go a step further and say that it's an essential topic, if not the essential topic. No survey of the philosophy of any era or country is conceivable without it.
That being the case, I'll cheerfully concede that Intelligent Design is a valid and even a valuable subject to discuss in a philosophy class, so long as the discussion is put in its historical perspective, and revolves around questions of inference, authority, justification of truth claims, logic, and so forth. Ideally, such a class would acknowledge every individual's right to a personal belief or disbelief in an intelligent creator, while demolishing false arguments for (and inferences from) those beliefs wherever possible. The argument that evolution couldn't have happened because there are still monkeys living on earth, for instance, would be revealed as fallacious, as would the more general belief that the theory of evolution stands or falls depending on whether or not God exists.
In the real world, of course, things aren't that simple. As PZ Myers reports, A "Philosophy of Intelligent Design" course under discussion in California seems poised to fail as theology, philosophy, and science:
This class will take a close look at evolution as a theory and will discuss the scientific, biological, and Biblical aspects that suggest why Darwin's philosophy is not rock solid. This class will discuss Intelligent Design as an alternative response to evolution. Topics that wlll be covered are the age of the earth, a world wide flood, dinosaurs, pre-human fossils, dating methods, DNA, radioisotopes, and geological evidence. Physical and chemical evidence will be presented suggesting the earth is thousands of years old, not billions. The class will include lecture discussions, guest speakers, and videos. The class grade will be based on a position paper in which students will support or refute the theory of evolution.I've bolded the last sentence because I find it particularly chilling. The person who'll grade these position papers, Sharon Lemberg, is a soccer coach and special-ed teacher with no background in science or philosophy. Even if she had those credentials, I think it's quite safe to say that no student who takes her class is going to "refute" the theory of evolution - assuming that "refutation" is defined as "disproof" or "falsification" - and that any student who thinks he or she has refuted it deserves a failing grade and a kick in the slats. We can put aside, in this discussion, the question of whether evolution is true or false; a more basic issue for a philosophy class is what would comprise a legitimate refutation of it, and what wouldn't. A Creationist video asserting that the earth is 6000 years old isn't a refutation of evolution; it's a product of ignorance, stupidity, or guile.
One of the many things that IDiots don't seem to grasp is that making or accepting a vacuous, illogical, pseudoscientific argument for God doesn't glorify His name; on the contrary, it misrepresents science, degrades religion, and makes believers look ignorant and insecure. People like Ms. Lemberg want to have their cake and eat it too; they want the scientific gravitas that comes from invoking DNA and radioisotopes, but they also want to ignore the norms and standards from which science derives whatever authority it has. As such, they remind me of Renaissance figures like Athanasius Kircher, whose "miraculous" devices surreptitiously exploited scientific principles in order to demonstrate, by analogy, the operation of occult powers. Except that Kircher was a genius, and these people are fools.