We doubt that Julius is white. There is almost no chance that Mary is in the school. It is certain that Bernhard is gray. There is almost no chance that if 'Bernhard is gray and Julius is white' then Emily is a cat. There is little chance that if 'Mary is in the school' or 'Julius is white' or both then Sandra left the football. It is highly likely that if 'Julius is white and Mary is in the school' then John discarded the apple.
It is impossible that 'Emily is a cat and Julius is white'.
It is impossible that 'Emily is a cat and Julius is white'.
It is almost certain that 'Emily is a cat and Julius is white'.

  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.
  0.02::factB.
  1.0::factC.
  %hop1
  0.02::factX:-and(factC,factA).
  0.1::factY:-or(factB,factA).
  0.9::factZ:-and(factA,factB).

  %hop2
  conclusion:-and(factX,factA).

  query(conclusion).
  
'Emily is a cat and Julius is white'.