We doubt that Julius is a swan. There is a better than even chance that Emily is a sheep. There is little chance that Bernhard is a swan. There is a better than even chance that if either 'Emily is a sheep' or 'Bernhard is a swan' but not both then Brian is a rhino. It is probably the case that if either 'Emily is a sheep' or 'Julius is a swan' but not both then Mary dropped the apple. Chances are slight that if 'Bernhard is a swan and Emily is a sheep' then Jason is tired.
It is certain that 'Mary dropped the apple' or 'Bernhard is a swan' or both.
Chances are about even that 'Mary dropped the apple' or 'Bernhard is a swan' or both.
It is certain that 'Mary dropped the apple' or 'Bernhard is a swan' 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
  0.2::factA.
  0.6::factB.
  0.1::factC.
  %hop1
  0.6::factX:-xor(factB,factC).
  0.7::factY:-xor(factB,factA).
  0.1::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Mary dropped the apple' or 'Bernhard is a swan' or both.