Chances are about even that Winona is a mouse. It is unlikely that Lily is a rhino. It is certain that Julius is a swan. It is probably not the case that if either 'Winona is a mouse' or 'Julius is a swan' but not both then Mary put down the apple. There is a better than even chance that if 'Winona is a mouse and Lily is a rhino' then Sandra left the milk. It is unlikely that if 'Julius is a swan' or 'Winona is a mouse' or both then John got the apple.
We believe that 'Mary put down the apple' or 'Sandra left the milk' or both.
It is unlikely that 'Mary put down the apple' or 'Sandra left the milk' or both.
We believe that 'Mary put down the apple' or 'Sandra left the milk' 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
  0.5::factA.
  0.2::factB.
  1.0::factC.
  %hop1
  0.25::factX:-xor(factA,factC).
  0.6::factY:-and(factA,factB).
  0.2::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Mary put down the apple' or 'Sandra left the milk' or both.