context: It is highly likely that Lily is green. There is a very good chance that Julius is a lion. There is almost no chance that John moved to the garden. There is a better than even chance that if 'Lily is green and Julius is a lion' then Sandra dropped the milk. There is a better than even chance that if 'John moved to the garden' or 'Julius is a lion' or both then Mary discarded the milk. Chances are slight that if 'John moved to the garden' or 'Lily is green' or both then Bernhard is green.
hypothesis: There is almost no chance that either 'Lily is green' or 'Mary discarded the milk' but not both.
valid_hypothesis: Chances are about even that either 'Lily is green' or 'Mary discarded the milk' but not both.
invalid_hypothesis: There is almost no chance that either 'Lily is green' or 'Mary discarded the milk' 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
    0.9::factA.
    0.8::factB.
    0.02::factC.
    %hop1
    0.6::factX:-and(factA,factB).
    0.6::factY:-or(factC,factB).
    0.1::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-xor(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Lily is green' or 'Mary discarded the milk' but not both.