context: It is highly likely that John picked up the apple. There is a very good chance that Winona is a wolf. It is unlikely that Lily is gray. There is little chance that if 'Lily is gray' or 'John picked up the apple' or both then Bernhard is a frog. There is almost no chance that if 'Winona is a wolf and Lily is gray' then Mary moved to the garden. It is unlikely that if 'John picked up the apple and Lily is gray' then Brian is a swan.
hypothesis: There is a very good chance that 'Bernhard is a frog and John picked up the apple'.
valid_hypothesis: Chances are slight that 'Bernhard is a frog and John picked up the apple'.
invalid_hypothesis: There is a very good chance that 'Bernhard is a frog and John picked up the apple'.
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.
    0.8::factB.
    0.2::factC.
    %hop1
    0.1::factX:-or(factC,factA).
    0.02::factY:-and(factB,factC).
    0.2::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-and(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is a frog and John picked up the apple'.