context: It is almost certain that Julius is green. Chances are about even that Brian is white. There is a very good chance that John discarded the apple. It is likely that if 'Brian is white' or 'Julius is green' or both then Sandra dropped the milk. We believe that if 'Julius is green' or 'John discarded the apple' or both then Bernhard is a frog. It is improbable that if 'Julius is green and John discarded the apple' then Mary went to the bedroom.
hypothesis: It is probably not the case that 'Sandra dropped the milk and Brian is white'.
valid_hypothesis: It is probably not the case that 'Sandra dropped the milk and Brian is white'.
invalid_hypothesis: It is probably the case that 'Sandra dropped the milk and Brian is white'.
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
    0.95::factA.
    0.5::factB.
    0.8::factC.
    %hop1
    0.7::factX:-or(factB,factA).
    0.75::factY:-or(factA,factC).
    0.1::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-and(factX,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra dropped the milk and Brian is white'.