context: It is almost certain that Fred put down the apple. There is little chance that Bernhard is a frog. It is probable that Jeff went to the bedroom. It is improbable that if 'Bernhard is a frog' or 'Jeff went to the bedroom' or both then Sandra took the football. It is probably the case that if 'Jeff went to the bedroom and Fred put down the apple' then Greg is gray. Chances are slight that if 'Jeff went to the bedroom' or 'Fred put down the apple' or both then Lily is green.
hypothesis: There is little chance that 'Sandra took the football' or 'Fred put down the apple' or both.
valid_hypothesis: It is almost certain that 'Sandra took the football' or 'Fred put down the apple' or both.
invalid_hypothesis: There is little chance that 'Sandra took the football' or 'Fred put down 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
    0.95::factA.
    0.1::factB.
    0.7::factC.
    %hop1
    0.1::factX:-or(factB,factC).
    0.7::factY:-and(factC,factA).
    0.1::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-or(factX,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra took the football' or 'Fred put down the apple' or both.