context: Chances are slight that Lily is a rhino. It is impossible that Brian is white. It is likely that John dropped the milk. We believe that if 'Lily is a rhino and Brian is white' then Emily is a mouse. It is certain that if 'John dropped the milk' or 'Lily is a rhino' or both then Mary is in the hallway. It is probable that if either 'Lily is a rhino' or 'John dropped the milk' but not both then Greg is a swan.
hypothesis: It is improbable that 'Lily is a rhino' or 'Brian is white' or both.
valid_hypothesis: It is improbable that 'Lily is a rhino' or 'Brian is white' or both.
invalid_hypothesis: It is probably the case that 'Lily is a rhino' or 'Brian is white' 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.
    0.0::factB.
    0.7::factC.
    %hop1
    0.75::factX:-and(factA,factB).
    1.0::factY:-or(factC,factA).
    0.7::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-or(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is a rhino' or 'Brian is white' or both.