It is probable that Mary dropped the milk. There is almost no chance that Lily is white. It is impossible that John went to the garden. It is probably the case that if 'John went to the garden' or 'Lily is white' or both then Yann is bored. It is impossible that if 'Mary dropped the milk and Lily is white' then Julius is a lion. Chances are about even that if 'Mary dropped the milk' or 'Lily is white' or both then Emily is a cat.
It is probable that 'Yann is bored' or 'Mary dropped the milk' or both.
It is probable that 'Yann is bored' or 'Mary dropped the milk' or both.
We doubt that 'Yann is bored' or 'Mary dropped the milk' 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
  0.7::factA.
  0.02::factB.
  0.0::factC.
  %hop1
  0.7::factX:-or(factC,factB).
  0.0::factY:-and(factA,factB).
  0.5::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Yann is bored' or 'Mary dropped the milk' or both.