We believe that Emily is a sheep. It is highly likely that Sandra took the football. There is a very good chance that John dropped the apple. It is highly unlikely that if 'Sandra took the football' or 'Emily is a sheep' or both then Lily is a swan. We believe that if 'John dropped the apple' or 'Sandra took the football' or both then Mary went to the bedroom. Chances are slight that if 'Sandra took the football and John dropped the apple' then Bernhard is white.
It is unlikely that 'Sandra took the football' or 'Lily is a swan' or both.
It is highly likely that 'Sandra took the football' or 'Lily is a swan' or both.
It is unlikely that 'Sandra took the football' or 'Lily 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
  0.75::factA.
  0.9::factB.
  0.8::factC.
  %hop1
  0.05::factX:-or(factB,factA).
  0.75::factY:-or(factC,factB).
  0.1::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Sandra took the football' or 'Lily is a swan' or both.