context: It is highly unlikely that Bernhard is white. We believe that Mary left the football. It is highly unlikely that Greg is a frog. It is highly unlikely that if either 'Bernhard is white' or 'Greg is a frog' but not both then Brian is white. Chances are slight that if either 'Mary left the football' or 'Bernhard is white' but not both then Emily is a sheep. It is probably not the case that if 'Bernhard is white and Greg is a frog' then John went to the bedroom.
hypothesis: Chances are slight that 'Emily is a sheep' or 'Greg is a frog' or both.
valid_hypothesis: Chances are slight that 'Emily is a sheep' or 'Greg is a frog' or both.
invalid_hypothesis: It is probably the case that 'Emily is a sheep' or 'Greg 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
    0.05::factA.
    0.75::factB.
    0.05::factC.
    %hop1
    0.05::factX:-xor(factA,factC).
    0.1::factY:-xor(factB,factA).
    0.25::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-or(factY,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Emily is a sheep' or 'Greg is a frog' or both.