context: There is a very good chance that Mary dropped the apple. Chances are slight that John went to the kitchen. It is highly unlikely that Lily is a swan. It is probable that if either 'Mary dropped the apple' or 'Lily is a swan' but not both then Daniel got the milk. Chances are slight that if either 'Mary dropped the apple' or 'Lily is a swan' but not both then Bernhard is a rhino. It is improbable that if 'John went to the kitchen' or 'Lily is a swan' or both then Brian is green.
hypothesis: It is highly unlikely that 'Lily is a swan' or 'Brian is green' or both.
valid_hypothesis: It is highly unlikely that 'Lily is a swan' or 'Brian is green' or both.
invalid_hypothesis: It is certain that 'Lily is a swan' or 'Brian is green' 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
    0.8::factA.
    0.1::factB.
    0.05::factC.
    %hop1
    0.7::factX:-xor(factA,factC).
    0.1::factY:-xor(factA,factC).
    0.1::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-or(factC,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is a swan' or 'Brian is green' or both.