context: It is unlikely that Fred went to the garden. It is unlikely that Mary discarded the milk. It is probably not the case that Winona is a mouse. It is certain that if either 'Fred went to the garden' or 'Winona is a mouse' but not both then Julius is a swan. It is almost certain that if 'Mary discarded the milk' or 'Winona is a mouse' or both then Jason is tired. We doubt that if either 'Mary discarded the milk' or 'Winona is a mouse' but not both then Brian is a frog.
hypothesis: It is probably the case that either 'Fred went to the garden' or 'Brian is a frog' but not both.
valid_hypothesis: It is probably not the case that either 'Fred went to the garden' or 'Brian is a frog' but not both.
invalid_hypothesis: It is probably the case that either 'Fred went to the garden' or 'Brian is a frog' 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
    0.2::factA.
    0.2::factB.
    0.25::factC.
    %hop1
    1.0::factX:-xor(factA,factC).
    0.95::factY:-or(factB,factC).
    0.2::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-xor(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Fred went to the garden' or 'Brian is a frog' but not both.