Knowledge Level Learning

In Prolog-EBG the $h$ follows (logically) directly from B alone, independent of D. So, why do we need examples?
Examples focus Prolog-EBG on generating rules that cover the distribution of instances that occur.
So, will it ever learn to classify an instance that could not be classified by B?
No. Since $B \entails h$ then any classification entailed by $h$ is also entailed by $B$.
OK, so this this a problem with all analytical learning methods?