context: Chances are slight that John went to the garden. It is probable that Julius is green. It is improbable that Bernhard is yellow. We believe that if either 'Bernhard is yellow' or 'John went to the garden' but not both then Mary dropped the milk. It is likely that if 'John went to the garden and Julius is green' then Daniel got the football. There is a very good chance that if 'Julius is green' or 'Bernhard is yellow' or both then Greg is white.
hypothesis: There is a very good chance that 'Mary dropped the milk and John went to the garden'.
valid_hypothesis: It is highly unlikely that 'Mary dropped the milk and John went to the garden'.
invalid_hypothesis: There is a very good chance that 'Mary dropped the milk and John went to the garden'.
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.
    0.7::factB.
    0.1::factC.
    %hop1
    0.75::factX:-xor(factC,factA).
    0.7::factY:-and(factA,factB).
    0.8::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-and(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary dropped the milk and John went to the garden'.