context: It is improbable that Julius is a frog. It is unlikely that Winona is a wolf. There is almost no chance that Mary picked up the apple. We believe that if either 'Winona is a wolf' or 'Julius is a frog' but not both then Jeff went to the garden. It is almost certain that if 'Winona is a wolf' or 'Mary picked up the apple' or both then Jessica is a sheep. It is improbable that if 'Mary picked up the apple and Winona is a wolf' then Brian is a swan.
hypothesis: We doubt that 'Winona is a wolf' or 'Jessica is a sheep' or both.
valid_hypothesis: We doubt that 'Winona is a wolf' or 'Jessica is a sheep' or both.
invalid_hypothesis: It is probably the case that 'Winona is a wolf' or 'Jessica is a sheep' 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.
    0.2::factB.
    0.02::factC.
    %hop1
    0.75::factX:-xor(factB,factA).
    0.95::factY:-or(factB,factC).
    0.1::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-or(factB,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a wolf' or 'Jessica is a sheep' or both.