context: We believe that Greg is a swan. It is probably the case that Bernhard is a frog. It is highly unlikely that Jessica is a sheep. There is a very good chance that if 'Greg is a swan and Bernhard is a frog' then John went to the office. It is almost certain that if either 'Jessica is a sheep' or 'Bernhard is a frog' but not both then Lily is yellow. It is likely that if 'Greg is a swan' or 'Jessica is a sheep' or both then Mary got the apple.
hypothesis: It is almost certain that 'Greg is a swan and Lily is yellow'.
valid_hypothesis: Chances are about even that 'Greg is a swan and Lily is yellow'.
invalid_hypothesis: It is almost certain that 'Greg is a swan and Lily is yellow'.
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
    0.75::factA.
    0.7::factB.
    0.05::factC.
    %hop1
    0.8::factX:-and(factA,factB).
    0.95::factY:-xor(factC,factB).
    0.7::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-and(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a swan and Lily is yellow'.