David Lightman: [On the computer] Hello, are you still playing the game?
Joshua: Of course. I should reach Defcon 1 and release my missiles in 28 hours. Would you like to see some projected kill ratios?
David Lightman: Sixty-nine percent of the housing destroyed. Seventy-two million people dead. [Types into computer] Is this a game or is it real?
Joshua: What's the difference?
Stephen Falken: The whole point was to find a way to practise nuclear war without destroying ourselves. To get the computers to learn from mistakes we couldn't afford to make. Except, I never could get Joshua to learn the most important lesson.
David Lightman: What's that?
Stephen Falken: Futility. That there's a time when you should just give up.
Jennifer: What kind of a lesson is that?
Stephen Falken: Did you ever play tic-tac-toe?
Jennifer: Yeah, of course.
Stephen Falken: But you don't anymore.
Jennifer: No.
Stephen Falken: Why?
Jennifer: Because it's a boring game. It's always a tie.
Stephen Falken: Exactly. There's no way to win. The game itself is pointless! But back at the war room, they believe you can win a nuclear war. That there can be "acceptable losses."
David: What kind of an asshole lives on an island and he doesn't even have a boat?
Jennifer: Maybe we can swim for it. How far do you think it is?
David: No, it's uh, 2 or 3 miles at least, maybe more.
Jennifer: Well, what do you say? Let's go for it.
David: No.
Jennifer: Come on!
David: No! I can't swim
Jennifer: You can't swim?
David: No, I can't. Okay, Wonder Woman? I can't swim.
Jennifer: Well, what kind of an asshole grows up in Seattle and doesn't even know how to swim?
Answer: While merely speculation, the WOPR is not alive and knows only what it's been programmed to do. It would have no concept of life or death, and as such would see no difference between the simulation and the real thing. That being said, an easy way to make it see the difference would be to program it to not waste physical resources. It would then see the use of all its actual warheads as less desirable.