context: Chances are about even that Bernhard is gray. It is almost certain that Winona is a mouse. It is certain that Brian is yellow. It is certain that if 'Brian is yellow and Bernhard is gray' then Mary left the football. It is unlikely that if 'Winona is a mouse and Brian is yellow' then Greg is a frog. It is unlikely that if either 'Bernhard is gray' or 'Winona is a mouse' but not both then John discarded the apple.
hypothesis: It is almost certain that 'Bernhard is gray' or 'Winona is a mouse' or both.
valid_hypothesis: It is almost certain that 'Bernhard is gray' or 'Winona is a mouse' or both.
invalid_hypothesis: It is impossible that 'Bernhard is gray' or 'Winona is a mouse' 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
    0.5::factA.
    0.95::factB.
    1.0::factC.
    %hop1
    1.0::factX:-and(factC,factA).
    0.2::factY:-and(factB,factC).
    0.2::factZ:-xor(factA,factB).
  
    %hop2
    conclusion:-or(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is gray' or 'Winona is a mouse' or both.