Yes, this time you struck a hard problem. I can imagine the unknown speaker. He is probably an assistant to the guest of honor, perhaps already a minor official, a young man with the brightest prospects. I will press him as to whether he did not after all feel conscious of something which may have worked in opposition to the demand that he do honor to the chief. What a fine success I'll have! He becomes impatient and suddenly bursts out on me, "Look here, you'd better stop this cross-examination, or I'll get unpleasant. Why, you'll spoil my whole career with your suspicions. I simply said '_auf_-gestossen' instead of '_an_-gestossen,' because I'd already said '_auf_' twice in the same sentence. It's the thing that Meringer calls a perservation, and there's no other meaning that you can twist out of it. Do you understand me? That's all." H'm, this is a surprising reaction, a really energetic denial. I see that there is nothing more to be obtained from the young man, but I also remark to myself that he betrays a strong personal interest in having his slip mean nothing. Perhaps you, too, agree that it is not right for him immediately to become so rude over a purely theoretical investigation, but, you will conclude, he really must know what he did and did not mean to say. Really? Perhaps that's open to question nevertheless. But now you think you have me. "So that is your technique," I hear you say. "When the person who has committed a slip gives an explanation which fits your theory, then you declare him the final authority on the subject. 'He says so himself!' But if what he says does not fit into your scheme, then you suddenly assert that what he says does not count, that one need not believe him." Yet that is certainly true. I can give you a similar case in which the procedure is apparently just as monstrous. When a defendant confesses to a deed, the judge believes his confession. But if he denies it, the judge does not believe him. Were it otherwise, there would be no way to administer the law, and despite occasional miscarriages you must acknowledge the value of this system. Well, are you then the judge, and is the person who committed the slip a defendant before you? Is a slip of the tongue a crime?