If it can't be expressed in figures, it is not science; it is opinion. It has long been known that one horse can run faster than another - but which one? Differences are crucial.
Robert A. HeinleinA handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method.
Robert A. Heinlein