I think there is a science of intelligence which (in my opinion) is closely related to computation, biology, and production functions (in the economic sense). The difficulty is that there is much debate as to what constitutes intelligence: there aren't any easily definable results in the field of intelligence nor are there clear definitions.

There is also the engineering side: this is to create an intelligence. The engineering is driven by a vague sense of what an AI should be, and one builds theories to construct concrete subproblems and give a framework for developing solutions.

Either way this is very different than astrophysics where one is attempting to: say, explain the motions of the heavenly sphere: which have a regularity, simplicity, and clarity to them that is lacking in any formulation of the AI problem.

I would say that AI researchers do formulate theories about how to solve particular engineering problems for AI systems, and then they test them out by programming them (hopefully). I suppose I count, and that's certainly what I and my colleagues do. Most papers in my fields of interest (machine learning and speech recognition) usually include an "experiments" section. I think that when you know a bit more about the actually problems AI people are solving you'll find that quite a bit of progress has been achieved since the 1960's.