context: There is a better than even chance that Brian is white. There is almost no chance that Daniel grabbed the milk. It is certain that Mary went to the garden. It is almost certain that if 'Daniel grabbed the milk and Mary went to the garden' then Fred left the football. We doubt that if either 'Mary went to the garden' or 'Daniel grabbed the milk' but not both then Greg is a lion. It is probably not the case that if 'Daniel grabbed the milk' or 'Brian is white' or both then Julius is a swan.
hypothesis: It is certain that 'Daniel grabbed the milk' or 'Fred left the football' or both.
valid_hypothesis: There is almost no chance that 'Daniel grabbed the milk' or 'Fred left the football' or both.
invalid_hypothesis: It is certain that 'Daniel grabbed the milk' or 'Fred left the football' 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
    0.6::factA.
    0.02::factB.
    1.0::factC.
    %hop1
    0.95::factX:-and(factB,factC).
    0.2::factY:-xor(factC,factB).
    0.25::factZ:-or(factB,factA).
  
    %hop2
    conclusion:-or(factB,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Daniel grabbed the milk' or 'Fred left the football' or both.