«A part of an overall plan,» said Leighton. «The replicator, you see, is not a separate unit to be plugged into a preexisting whole. It is a strategy for the organization of the entire process. When I put the electrodes on by hand, there's no way I can ever put them on exactly the same way twice. I, myself, was inadvertently introducing variation into something that must be exactly the same every time. And look here.» He gestured toward a completely remodeled control console. «I have eliminated the red sliding switch you've so often seen me throw an instant before you-er-departed.»

«Then how do you start the final sequence?» asked Blade.

«I don't. Once the program is fed into the computer memory banks, only two switches remain active: Program Start and Program Stop. And when Program Start is pushed, the preliminary sequences begin and run themselves out, one after the other. That's nothing new. The innovation is that the impulse that starts the final sequence comes directly from the computer, automatically, when it comes to the end of the prelims. I never touch the controls unless I think something is going wrong. Then I hit Program Stop. Normally everything is completely automatic, including the closing of the box. The computer even turns itself off after you've been launched»

Blade asked, «What's the point of that? Oh wait, I see. The machine repeats every step exactly the same way every time, and thus should produce the same result, so long as nobody changes the program.»

Leighton beamed up at him. «Exactly! You should have been a scientist, my boy. You have the mind for it. What we had failed to see was that no human being could do things as perfectly as a machine, not even a human being as unusual as myself.»

Blade smiled at Lord Leighton's unconscious egotism. The scientist continued, «The only variation that remains is your thoughts. You must try to think of the same things every time you're going to the same place. Do you think you can do that?»