 What does the older man plan to do after this event?
But some men aren't sane; thus it isn't always so! You will, you know, so why quibble about it? At least, you always have ... or do ... or will. You'll get used to it, of course, but it will take about thirty years. And you can look at the revenue stamp date, if you still doubt my story. It's a real wrench when a man meets himself for the first time. So let's begin when you get up in half an hour and come out with me. Yes, it'll be pretty obvious it must be a time machine. You'll be puzzling over what I'll tell you, and you'll be getting used to the idea that you are the man who makes atomic power practical. You won't exactly believe it, but you'll want to go along. "Maybe it's no dimension—or it might be the fifth; if you're going to skip over the so-called fourth without traveling along it, you'd need a fifth. "But...." I let it go, and so do you. I figured out once that such a universe would need some seven or eight time and space dimensions. When you spend thirty years thinking about it, as I did—and you will—you get further and further from an answer. That means you either carry a small time field with you, or you are catching a small increment of time from the main field.
 retire
 retire  grow his company and make more money  go to another dimension  travel back in time again