context: It is probable that Fred is in the school. Chances are about even that Mary left the football. It is certain that Bernhard is green. It is highly unlikely that if 'Mary left the football and Bernhard is green' then Brian is white. There is a better than even chance that if 'Bernhard is green and Fred is in the school' then Winona is a mouse. Chances are slight that if 'Fred is in the school' or 'Bernhard is green' or both then Daniel dropped the apple.
hypothesis: It is highly unlikely that either 'Bernhard is green' or 'Winona is a mouse' but not both.
valid_hypothesis: There is a better than even chance that either 'Bernhard is green' or 'Winona is a mouse' but not both.
invalid_hypothesis: It is highly unlikely that either 'Bernhard is green' or 'Winona is a mouse' but not 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.
    0.5::factB.
    1.0::factC.
    %hop1
    0.05::factX:-and(factB,factC).
    0.6::factY:-and(factC,factA).
    0.1::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-xor(factC,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Bernhard is green' or 'Winona is a mouse' but not both.