context: Chances are slight that Bernhard is a frog. We doubt that Winona is a wolf. It is highly likely that John went to the office. It is probably not the case that if either 'Winona is a wolf' or 'John went to the office' but not both then Lily is yellow. There is little chance that if either 'Winona is a wolf' or 'Bernhard is a frog' but not both then Julius is a swan. We doubt that if 'John went to the office' or 'Bernhard is a frog' or both then Sandra got the milk.
hypothesis: It is probably not the case that 'Lily is yellow' or 'Bernhard is a frog' or both.
valid_hypothesis: It is probably not the case that 'Lily is yellow' or 'Bernhard is a frog' or both.
invalid_hypothesis: It is almost certain that 'Lily is yellow' or 'Bernhard is a frog' 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
    0.1::factA.
    0.2::factB.
    0.9::factC.
    %hop1
    0.25::factX:-xor(factB,factC).
    0.1::factY:-xor(factB,factA).
    0.2::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-or(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is yellow' or 'Bernhard is a frog' or both.