There is little chance that Gertrude is a mouse. We believe that Brian is a frog. Chances are about even that Julius is a lion. It is highly likely that if either 'Gertrude is a mouse' or 'Julius is a lion' but not both then Mary left the football. It is certain that if 'Gertrude is a mouse and Brian is a frog' then John went to the kitchen. It is likely that if either 'Julius is a lion' or 'Brian is a frog' but not both then Lily is yellow.
Chances are about even that 'John went to the kitchen' or 'Julius is a lion' or both.
Chances are about even that 'John went to the kitchen' or 'Julius is a lion' or both.
It is certain that 'John went to the kitchen' or 'Julius is a lion' 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
  0.1::factA.
  0.75::factB.
  0.5::factC.
  %hop1
  0.9::factX:-xor(factA,factC).
  1.0::factY:-and(factA,factB).
  0.7::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'John went to the kitchen' or 'Julius is a lion' or both.