context: It is highly unlikely that Jeff left the apple. It is certain that Winona is a mouse. It is highly likely that Greg is a lion. It is probable that if 'Jeff left the apple' or 'Greg is a lion' or both then John went to the office. There is a very good chance that if 'Greg is a lion' or 'Jeff left the apple' or both then Brian is a rhino. It is likely that if either 'Winona is a mouse' or 'Greg is a lion' but not both then Sandra dropped the milk.
hypothesis: There is a better than even chance that either 'John went to the office' or 'Jeff left the apple' but not both.
valid_hypothesis: There is a better than even chance that either 'John went to the office' or 'Jeff left the apple' but not both.
invalid_hypothesis: It is highly unlikely that either 'John went to the office' or 'Jeff left the apple' 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
    0.05::factA.
    1.0::factB.
    0.9::factC.
    %hop1
    0.7::factX:-or(factA,factC).
    0.8::factY:-or(factC,factA).
    0.7::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-xor(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'John went to the office' or 'Jeff left the apple' but not both.