context: It is probable that Julius is a lion. It is highly unlikely that Winona is a cat. We believe that Lily is gray. There is a very good chance that if 'Lily is gray' or 'Winona is a cat' or both then Greg is yellow. We believe that if 'Julius is a lion and Lily is gray' then John went to the garden. It is highly unlikely that if 'Julius is a lion' or 'Winona is a cat' or both then Bernhard is green.
hypothesis: It is impossible that 'Winona is a cat' or 'John went to the garden' or both.
valid_hypothesis: Chances are about even that 'Winona is a cat' or 'John went to the garden' or both.
invalid_hypothesis: It is impossible that 'Winona is a cat' or 'John went to the garden' 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
    0.7::factA.
    0.05::factB.
    0.75::factC.
    %hop1
    0.8::factX:-or(factC,factB).
    0.75::factY:-and(factA,factC).
    0.05::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-or(factB,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a cat' or 'John went to the garden' or both.