Oh, oops... almost missed a Kant moment... I am SO slipping!
A lie can not be universal law (told all the time) because if it were it would no longer work as one would always be distrustful. So... Truths must, by human nature, be sprinkled in with the lies to keep them believable. My guess is that Skinner from the realm of psychological conditioning would also agree to a variable reinforcement schedule for believing that included some truths in with the lies.

Ok... back to my nap.