It is probable that Julius is white. It is probably not the case that Daniel left the apple. Chances are slight that John went to the office. Chances are slight that if 'John went to the office and Daniel left the apple' then Brian is yellow. It is impossible that if either 'Julius is white' or 'Daniel left the apple' but not both then Greg is white. It is likely that if 'Julius is white and John went to the office' then Bernhard is a swan.
It is improbable that 'Bernhard is a swan' or 'John went to the office' or both.
It is improbable that 'Bernhard is a swan' or 'John went to the office' or both.
It is likely that 'Bernhard is a swan' or 'John went to the office' 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
  0.7::factA.
  0.25::factB.
  0.1::factC.
  %hop1
  0.1::factX:-and(factC,factB).
  0.0::factY:-xor(factA,factB).
  0.7::factZ:-and(factA,factC).

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

  query(conclusion).
  
'Bernhard is a swan' or 'John went to the office' or both.