It is highly likely that Julius is a frog. It is probably not the case that Sandra took the football. There is little chance that Bill went to the office. It is probably not the case that if 'Sandra took the football' or 'Julius is a frog' or both then Bernhard is a swan. We believe that if 'Julius is a frog and Bill went to the office' then Greg is yellow. There is a very good chance that if 'Sandra took the football' or 'Julius is a frog' or both then John discarded the apple.
There is a very good chance that 'Bill went to the office' or 'Bernhard is a swan' or both.
It is probably not the case that 'Bill went to the office' or 'Bernhard is a swan' or both.
There is a very good chance that 'Bill went to the office' or 'Bernhard is a swan' 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
  0.9::factA.
  0.25::factB.
  0.1::factC.
  %hop1
  0.25::factX:-or(factB,factA).
  0.75::factY:-and(factA,factC).
  0.8::factZ:-or(factB,factA).

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

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