context: There is a very good chance that John dropped the apple. Chances are slight that Bill went to the office. It is certain that Brian is green. It is unlikely that if 'John dropped the apple' or 'Brian is green' or both then Bernhard is a frog. There is almost no chance that if 'Brian is green' or 'John dropped the apple' or both then Mary took the football. Chances are slight that if 'Bill went to the office and Brian is green' then Julius is white.
hypothesis: It is likely that 'Bill went to the office and Bernhard is a frog'.
valid_hypothesis: There is almost no chance that 'Bill went to the office and Bernhard is a frog'.
invalid_hypothesis: It is likely that 'Bill went to the office and Bernhard is a frog'.
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.
    0.1::factB.
    1.0::factC.
    %hop1
    0.2::factX:-or(factA,factC).
    0.02::factY:-or(factC,factA).
    0.1::factZ:-and(factB,factC).
  
    %hop2
    conclusion:-and(factB,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Bill went to the office and Bernhard is a frog'.