context: It is highly likely that Bernhard is white. It is probably the case that Julius is yellow. There is a better than even chance that Lily is a frog. There is a very good chance that if either 'Bernhard is white' or 'Julius is yellow' but not both then Emily is a cat. We believe that if 'Bernhard is white' or 'Julius is yellow' or both then Mary left the football. Chances are slight that if 'Lily is a frog and Julius is yellow' then Brian is a lion.
hypothesis: Chances are about even that 'Julius is yellow and Lily is a frog'.
valid_hypothesis: Chances are about even that 'Julius is yellow and Lily is a frog'.
invalid_hypothesis: There is almost no chance that 'Julius is yellow and Lily 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
    0.9::factA.
    0.7::factB.
    0.6::factC.
    %hop1
    0.8::factX:-xor(factA,factB).
    0.75::factY:-or(factA,factB).
    0.1::factZ:-and(factC,factB).
  
    %hop2
    conclusion:-and(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is yellow and Lily is a frog'.