context: It is unlikely that John put down the milk. There is almost no chance that Bernhard is gray. It is improbable that Sandra left the milk. It is probable that if 'Sandra left the milk' or 'Bernhard is gray' or both then Daniel took the apple. Chances are about even that if either 'Bernhard is gray' or 'Sandra left the milk' but not both then Mary went to the kitchen. There is a very good chance that if 'John put down the milk and Bernhard is gray' then Julius is a swan.
hypothesis: It is almost certain that 'John put down the milk' or 'Mary went to the kitchen' or both.
valid_hypothesis: It is probably not the case that 'John put down the milk' or 'Mary went to the kitchen' or both.
invalid_hypothesis: It is almost certain that 'John put down the milk' or 'Mary went to the kitchen' or both.
problog: 
    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.
    0.1::factC.
    %hop1
    0.7::factX:-or(factC,factB).
    0.5::factY:-xor(factB,factC).
    0.8::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-or(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'John put down the milk' or 'Mary went to the kitchen' or both.