There is almost no chance that Brian is a lion. We doubt that Gertrude is a sheep. It is impossible that John went to the office. It is probably not the case that if 'John went to the office' or 'Gertrude is a sheep' or both then Sandra got the milk. Chances are slight that if 'Brian is a lion' or 'John went to the office' or both then Lily is a rhino. There is a very good chance that if 'John went to the office and Gertrude is a sheep' then Bernhard is gray.
It is highly likely that 'John went to the office' or 'Lily is a rhino' or both.
It is impossible that 'John went to the office' or 'Lily is a rhino' or both.
It is highly likely that 'John went to the office' or 'Lily is a rhino' or both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.02::factA.
  0.2::factB.
  0.0::factC.
  %hop1
  0.25::factX:-or(factC,factB).
  0.1::factY:-or(factA,factC).
  0.8::factZ:-and(factC,factB).

  %hop2
  conclusion:-or(factC,factY).

  query(conclusion).
  
'John went to the office' or 'Lily is a rhino' or both.