It is highly likely that Bernhard is gray. It is certain that Brian is a frog. It is highly likely that Mary went to the hallway. There is a better than even chance that if 'Mary went to the hallway' or 'Bernhard is gray' or both then Jessica is a cat. Chances are slight that if 'Brian is a frog and Bernhard is gray' then Jeff discarded the milk. Chances are about even that if 'Bernhard is gray' or 'Brian is a frog' or both then Daniel dropped the apple.
It is probably not the case that 'Jessica is a cat and Daniel dropped the apple'.
It is probably not the case that 'Jessica is a cat and Daniel dropped the apple'.
It is probably the case that 'Jessica is a cat and Daniel dropped the apple'.

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

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

  query(conclusion).
  
'Jessica is a cat and Daniel dropped the apple'.