It is that which reduces uncertainty. There is no fully satisfactory definition. One would be hard pressed to find another field of scientific inquiry in which every researcher gets to define the primary object of study for himself. Imagine if every chemist had to state to which definition of matter she was going to adhere, or if a biologist was forced to define life at the beginning of every lab report.
Information science is currently in such a time.
We have yet to agree on a core set of concepts. Our facts are in dispute. Our vocabulary is in a high state of flux. We are trying to define our object of study. None of these makes what we do any less of a science.