context: There is a very good chance that Brian is green. Chances are about even that Mary went to the office. There is a very good chance that Julius is a frog. Chances are about even that if 'Brian is green' or 'Julius is a frog' or both then Gertrude is a cat. It is probable that if 'Julius is a frog' or 'Mary went to the office' or both then Fred is in the cinema. It is highly unlikely that if 'Brian is green' or 'Mary went to the office' or both then John left the milk.
hypothesis: It is highly unlikely that 'Mary went to the office' or 'Julius is a frog' or both.
valid_hypothesis: It is highly likely that 'Mary went to the office' or 'Julius is a frog' or both.
invalid_hypothesis: It is highly unlikely that 'Mary went to the office' or 'Julius is a frog' or 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.
    0.5::factB.
    0.8::factC.
    %hop1
    0.5::factX:-or(factA,factC).
    0.7::factY:-or(factC,factB).
    0.05::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-or(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary went to the office' or 'Julius is a frog' or both.