context: It is highly unlikely that Mary dropped the apple. It is likely that Daniel got the football. It is highly unlikely that Brian is a frog. It is impossible that if either 'Mary dropped the apple' or 'Daniel got the football' but not both then Julius is gray. We doubt that if either 'Brian is a frog' or 'Mary dropped the apple' but not both then Bernhard is white. It is probably not the case that if 'Daniel got the football and Brian is a frog' then Lily is a rhino.
hypothesis: Chances are about even that 'Lily is a rhino' or 'Mary dropped the apple' or both.
valid_hypothesis: It is highly unlikely that 'Lily is a rhino' or 'Mary dropped the apple' or both.
invalid_hypothesis: Chances are about even that 'Lily is a rhino' or 'Mary dropped the apple' 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
    0.05::factA.
    0.7::factB.
    0.05::factC.
    %hop1
    0.0::factX:-xor(factA,factB).
    0.2::factY:-xor(factC,factA).
    0.25::factZ:-and(factB,factC).
  
    %hop2
    conclusion:-or(factZ,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is a rhino' or 'Mary dropped the apple' or both.