I wish I knew Great-great's name. If I knew his name and could find him, he'd confirm my story. I know what you're thinking. Believe me, I am not a paranoid. I....
What's that? His name's Haney, just like Angus Haney? That figures, I guess. George Haney. Well, truck him in for crying out loud. He'll confirm everything I say—
Here he is now. "Well, Jack am I glad to see you! They think I'm crazy. They're trying to tell me there's no such thing as time travel, but I ought to know. I come from the past. And you ought to know, because you went back there to destroy Angus Haney's prototype of a time machine so you wouldn't build one yourself, based on it, and be trapped back in my century. Right? Incidentally, Jack, you can forget all about the ten grand, just as long as you get me out of here and convince them I'm not crazy."
He stares at me. He's Great-great, all right. He frowns and says, "I could not possibly be interested. I never saw you before in my life. And obviously, there is no such thing as time travel." He shakes his head sadly and starts to leave.
"Wait!" I cry. "You don't understand. I understand now. Of course you wouldn't know. You wouldn't remember. Because if you destroyed Angus Haney's time machine there wouldn't be any such thing as time travel and you wouldn't have built your own machine. So you forgot. The episode sort of never existed for you."
"I'm terribly sorry I can't help you, fellow." A genuine look of sympathy in his eyes.
"There's no such thing as time travel. For everybody but me. I'm the one guy who proved time travel was possible—before the first and only time machine was destroyed."
He leaves. The head medics confer. I know what they're saying. I'm nuts. Time travel is impossible so I must be nuts.
But we know better, don't we?