context: There is a very good chance that Lily is a swan. It is probably the case that John got the football. It is unlikely that Mary went to the office. It is impossible that if 'Mary went to the office' or 'Lily is a swan' or both then Bernhard is a rhino. There is a very good chance that if 'Lily is a swan and John got the football' then Greg is yellow. There is a better than even chance that if 'Lily is a swan and John got the football' then Emily is a sheep.
hypothesis: It is probable that either 'Lily is a swan' or 'Greg is yellow' but not both.
valid_hypothesis: It is probably not the case that either 'Lily is a swan' or 'Greg is yellow' but not both.
invalid_hypothesis: It is probable that either 'Lily is a swan' or 'Greg is yellow' 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
    0.8::factA.
    0.7::factB.
    0.2::factC.
    %hop1
    0.0::factX:-or(factC,factA).
    0.8::factY:-and(factA,factB).
    0.6::factZ:-and(factA,factB).
  
    %hop2
    conclusion:-xor(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Lily is a swan' or 'Greg is yellow' but not both.