One of the most common questions computer science professors used to ask about my research went something like this: "What you're doing is very clever, and I see how it's useful, but how is it science?" At first, I tried coming up with convoluted explanations for why my research was actually scientific and even went and published a paper in the journal named Science. But I've been told that the best defense is a good offense, so at some point I switched to answering with something like "It's not. How is your research science?"
Fortunately, this type of questioning has stopped. Perhaps the word got around that I myself didn't consider my research science so people just stopped asking. But the one thing that always struck me was how most computer science professors could not answer this question adequately about their own research. Which made wonder: is computer science really a science? It has a lot of math, but math is not science. It also has a lot of engineering -- I'm not 100% sure what the difference is between engineering and science, but I'm told there is one.
I do find it funny that you can get a PhD in computer "science" without ever having taken a class in experimental design, in research methods or in statistics. I also find it funny that we need to put the word "science" in the name of our field: political science, actuarial science, computer science.
I'm not sure whether cs is actually a science, but the real question is "who cares?" I don't.