There is almost no chance that Mary went to the kitchen. It is likely that John got the apple. There is little chance that Bernhard is a frog. It is impossible that if 'Bernhard is a frog and Mary went to the kitchen' then Jessica is a cat. Chances are about even that if either 'Mary went to the kitchen' or 'John got the apple' but not both then Greg is a rhino. It is improbable that if either 'Mary went to the kitchen' or 'John got the apple' but not both then Lily is a swan.
It is almost certain that either 'Jessica is a cat' or 'Bernhard is a frog' but not both.
It is improbable that either 'Jessica is a cat' or 'Bernhard is a frog' but not both.
It is almost certain that either 'Jessica is a cat' or 'Bernhard is a frog' but not 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
  0.02::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.0::factX:-and(factC,factA).
  0.5::factY:-xor(factA,factB).
  0.1::factZ:-xor(factA,factB).

  %hop2
  conclusion:-xor(factX,factC).

  query(conclusion).
  
Either 'Jessica is a cat' or 'Bernhard is a frog' but not both.