It is highly likely that Mary dropped the apple. It is certain that Greg is a lion. It is unlikely that Julius is white. It is improbable that if 'Julius is white and Mary dropped the apple' then Jessica is a cat. It is likely that if 'Julius is white and Greg is a lion' then Lily is green. There is almost no chance that if 'Mary dropped the apple' or 'Julius is white' or both then John took the football.
It is improbable that 'Jessica is a cat' or 'Lily is green' or both.
It is improbable that 'Jessica is a cat' or 'Lily is green' or both.
We believe that 'Jessica is a cat' or 'Lily is green' 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.
  1.0::factB.
  0.2::factC.
  %hop1
  0.1::factX:-and(factC,factA).
  0.7::factY:-and(factC,factB).
  0.02::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Jessica is a cat' or 'Lily is green' or both.