context: It is highly likely that Sandra left the milk. There is a better than even chance that Jessica is a mouse. It is highly unlikely that Greg is a frog. It is unlikely that if 'Greg is a frog' or 'Sandra left the milk' or both then Lily is a lion. It is probably the case that if either 'Greg is a frog' or 'Sandra left the milk' but not both then Julius is a swan. We doubt that if 'Sandra left the milk' or 'Jessica is a mouse' or both then Mary moved to the garden.
hypothesis: It is highly likely that 'Sandra left the milk' or 'Lily is a lion' or both.
valid_hypothesis: It is highly likely that 'Sandra left the milk' or 'Lily is a lion' or both.
invalid_hypothesis: It is probably not the case that 'Sandra left the milk' or 'Lily is a lion' 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
    0.9::factA.
    0.6::factB.
    0.05::factC.
    %hop1
    0.2::factX:-or(factC,factA).
    0.7::factY:-xor(factC,factA).
    0.2::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-or(factA,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra left the milk' or 'Lily is a lion' or both.