context: It is probable that John moved to the garden. There is a very good chance that Jason is thirsty. It is highly unlikely that Gertrude is a sheep. There is little chance that if 'John moved to the garden and Gertrude is a sheep' then Julius is a rhino. It is improbable that if either 'Jason is thirsty' or 'Gertrude is a sheep' but not both then Mary put down the apple. It is unlikely that if 'Jason is thirsty' or 'Gertrude is a sheep' or both then Greg is a lion.
hypothesis: We believe that either 'Jason is thirsty' or 'Gertrude is a sheep' but not both.
valid_hypothesis: We believe that either 'Jason is thirsty' or 'Gertrude is a sheep' but not both.
invalid_hypothesis: It is highly unlikely that either 'Jason is thirsty' or 'Gertrude is a sheep' 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.
    0.8::factB.
    0.05::factC.
    %hop1
    0.1::factX:-and(factA,factC).
    0.1::factY:-xor(factB,factC).
    0.2::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-xor(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Jason is thirsty' or 'Gertrude is a sheep' but not both.