There is a better than even chance that John discarded the apple. There is a better than even chance that Bill moved to the office. It is certain that Sandra dropped the milk. It is certain that if 'John discarded the apple' or 'Bill moved to the office' or both then Julius is a frog. Chances are slight that if 'Sandra dropped the milk and John discarded the apple' then Lily is white. There is a very good chance that if 'Bill moved to the office' or 'John discarded the apple' or both then Mary went to the bedroom.
There is a very good chance that 'Julius is a frog' or 'Lily is white' or both.
There is a very good chance that 'Julius is a frog' or 'Lily is white' or both.
There is little chance that 'Julius is a frog' or 'Lily is white' 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
  0.6::factA.
  0.6::factB.
  1.0::factC.
  %hop1
  1.0::factX:-or(factA,factB).
  0.1::factY:-and(factC,factA).
  0.8::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Julius is a frog' or 'Lily is white' or both.