context: It is probably not the case that Brian is a swan. It is probably the case that Greg is white. There is a very good chance that Lily is a frog. It is improbable that if 'Greg is white and Brian is a swan' then John grabbed the milk. There is a very good chance that if either 'Greg is white' or 'Brian is a swan' but not both then Daniel took the apple. It is probably the case that if 'Lily is a frog' or 'Greg is white' or both then Bernhard is white.
hypothesis: There is a better than even chance that 'Greg is white and Lily is a frog'.
valid_hypothesis: There is a better than even chance that 'Greg is white and Lily is a frog'.
invalid_hypothesis: It is highly unlikely that 'Greg is white and Lily is a frog'.
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
    0.25::factA.
    0.7::factB.
    0.8::factC.
    %hop1
    0.1::factX:-and(factB,factA).
    0.8::factY:-xor(factB,factA).
    0.7::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-and(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is white and Lily is a frog'.