After a brilliant but asocial mathematician, John Nash, accepts secret work in cryptography, his life takes a turn for the nightmarish.

Alicia: How big is the universe?
Nash: Infinite.
Alicia: How do you know?
Nash: I know because all the data indicates it's infinite.
Alicia: But it hasn't been proven yet.
Nash: No.
Alicia: You haven't seen it.
Nash: No.
Alicia: How do you know for sure?
Nash: I don't, I just believe it.
Alicia: It's the same with love I guess.
Dr. Rosen: Imagine if you suddenly learned that the people, the places, the moments most important to you were not gone, not dead, but worse, had never been. What kind of hell would that be?
Hansen: So how about it, Nash? You scared?
Nash: Terrified... mortified... petrified... stupefied... by you.
[from deleted scene]
Nash: Perhaps it is good to have a beautiful mind, but an even greater gift is to discover a beautiful heart.
Nash: What truly is logic? Who decides reason? My quest has taken me to the physical, the metaphysical, the delusional, and back. I have made the most important discovery of my career - the most important discovery of my life. It is only in the mysterious equations of love that any logic or reasons can be found. I am only here tonight because of you
[looking at and speaking to Alicia]
Nash: You are the only reason I am. You are all my reasons. Thank you.
[applause from audience]
Nash: Classes will dull your mind, destroy the potential for authentic creativity.
Nash: I find you attractive. Your aggressive moves toward me... indicate that you feel the same way. But still, ritual requires that we continue with a number of platonic activities... before we have sex. I am proceeding with these activities, but in point of actual fact, all I really want to do is have intercourse with you as soon as possible.
Nash: Are you gonna slap me now?
Nash: Can you see him?
Student: Yeah.
Nash: Okay. I am always suspicious of new people. Now that I know you're real, who are you, and what can I do for you?
Alicia: I need to believe, that something extraordinary is possible.
Nash: If we all go for the blonde and block each other, not a single one of us is going to get her. So then we go for her friends, but they will all give us the cold shoulder because no on likes to be second choice. But what if none of us goes for the blonde? We won't get in each other's way and we won't insult the other girls. It's the only way to win. It's the only way we all get laid.
Nash: You once said that God must be a painter because he gave us so many colors.
Alicia: I didn't think you were listening...
Nash: I was listening.
Charles: Nothing's ever for sure, John. That's the only sure thing I do know.
Nash: This class will be a waste of your - and what is infinitely worse - my time.
Nash: Alicia, does our relationship warrant long-term commitment? I need some kind of proof, some kind of verifiable, empirical data.
Alicia: I'm sorry, just give me a moment to redefine my girlish notions of romance.
Nash: I've made the most important discovery of my life. It's only in the mysterious equation of love that any logic or reasons can be found. I'm only here tonight because of you. You are the only reason I am... you are all my reasons.
Nash: I've gotten used to ignoring them and I think, as a result, they've kind of given up on me. I think that's what it's like with all our dreams and our nightmares, Martin, we've got to keep feeding them for them to stay alive.
Nash: [to Thomas King] I still see things that are not here. I just choose not to acknowledge them. Like a diet of the mind, I just choose not to indulge certain appetites; like my appetite for patterns; perhaps my appetite to imagine and to dream.
Alicia: [about the stars] I once tried to count them all. I, actually, made it to 4,348.
Nash: You are exceptionally odd.
Alicia: I bet you're very popular with the girls.
Nash: She never gets old! Marcee can't be real; she never gets old!
Nash: Find a truly original idea. It is the only way I will ever distinguish myself. It is the only way I will ever matter.
Alicia: The problem you left on the board, I solved it.
John Nash: No, you didn't.
Alicia: You didn't even look!
John Nash: I never said the vector fields were rational functions... Your solution is elegant, though ultimately incorrect.
Alicia: You want to know what's real? This...
[putting her hand on his heart and his hand on her face]
Alicia: ... this is real.
Alicia: I was wondering Professor Nash, if I could take you to dinner?
[he hesitates]
Alicia: You do eat don't you?
[Hansen is concerned about John still having hallucinations]
Nash: They are my past. Everyone is haunted by their past.
Nash: I don't exactly know what I am required to say in order for you to have intercourse with me. But could we assume that I said all that. I mean essentially we are talking about fluid exchange right? So could we go just straight to the sex.
Alicia: God must be a painter. Why else would we have so many colors?
Nash: In competitive behavior someone always loses.
Charles: Well, my niece knows that, John, and she's about this high.
Nash: See if I derive an equilibrium where prevalence is a non-singular event where nobody loses, can you imagine the effect that would have on conflict scenarios, arm negotiations...
Charles: When did you last eat?
Nash: ...currency exchange?
Charles: When did you last eat? You know, food.
Nash: You have no respect for cognitive reverie, you know that?
Charles: Yes. But pizza - now, pizza I have enormous respect for. And of course beer.
Nash: [throws stuff down and follows] I have respect for beer. I have respect for beer!
[first lines]
Helinger: Mathematicians won the war. Mathematicians broke the Japanese codes... and built the A-bomb. Mathematicians... like you. The stated goal of the Soviets is global Communism. In medicine or economics, in technology or space, battle lines are being drawn. To triumph, we need results. Publishable, applicable results. Now who among you will be the next Morse? The next Einstein? Who among you will be the vanguard of democracy, freedom, and discovery? Today, we bequeath America's future into your able hands. Welcome to Princeton, gentlemen.
Charles: Her husband was too drunk to know he was too drunk to drive.
Charles: [offering Nash a flask of whiskey] Listen. If we can't break the ice, how 'bout we drown it?
Alicia: It's called "life," John. Activities available; just add meaning.
Nash: Good morning, eager young minds
MIT Student: Can we open up the window, Professor? It's hot in here.
John Nash: Your comfort comes second to my ability to hear my own voice.
Nash: There has to be a mathematical explanation for how bad that tie is.
Nash: There's no point in being nuts if you can't have a little fun.
Charles: That Isaac Newton fellow was right.
Nash: He was on to something.
Charles: Clever boy.
Parcher: Man is capable of as much atrocity as he has imagination.
Nash: It looks like you won after all.
Hansen: No. They were wrong, John. No one wins.
[showing Charles one of his window equations]
Nash: This is a group playing touch football. This is a flock of pigeons fighting over bread crumbs. And this is a woman chasing a man who stole her purse.
Charles: John, you watched a mugging. That's weird.
Dr. Rosen: You can't reason your way out of this!
Nash: Why not? Why can't I?
Dr. Rosen: Because your mind is where the problem is in the first place!
John Nash: And then, on the way home, Charles was there again. Sometimes I miss talking to him. Maybe Rosen is right. Maybe I have to think about going back to the hospital.
Alicia Nash: Maybe try again tomorrow.
Nash: [to Charles] The prodigal roommate revealed. "Saw my name on the lecture slate." YOU LYING SON OF A BITCH!
Dr. Rosen: Who are you talking to? Tell me who you see.
Nash: How do you say "Charles Herman" in Russian?
Nash: Classes will dull your mind.
General: You ever... just *know* something, Dr. Nash?
Nash: Constantly.
Hansen: Nash. Who's winning - you, or you?
John Nash: Hello, Martin.
Martin Hansen: Jesus Christ.
John Nash: No. I don't have that one. My savior complex takes a different form.
Charles: So what's your story? You the poor kid that never got to go to Exeter or Andover?
Nash: Despite my privileged upbringing, I'm actually quite well-balanced. I have a chip on both shoulders.
[John meets Charles' niece]
Nash: She's so small.
Charles: Well, she's young, John. That's how they come.
Dr. Rosen: My name is Rosen, Dr. Rosen. I am a psychiatrist.
Charles: Officer, I saw the driver who hit me His name was Johny Walker.
Nash: Well, Martin Hansen. It is Martin, isn't it?
Hansen: Why yes, John, it is.
Nash: I assume you've gotten quite used to miscalculation. I read your pre-prints. Both of 'em. One on Nazi scientists and the other one on, uh... non-linear equations, and I'm extremely confident that there's not one seminal or innovative idea in either one of them... Enjoy your punch.
Alicia: What you don't know... is if I want to marry you.
Charles: Mathematics... mathematics is never going to lead you to higher truth and you know why? Because it's boring!
Charles: Is my roommate a dick?
Charles: I arrived last night. Right in time for English Department cocktails. The cock was mine. The tail belonged to a lovely young thing with a passion for D.H. Lawrence.
Nash: I will not buy you gentlemen beer.
Bender: Oh, we're not here for beer, my friend.
Sol: Alicia, John's always been a little... weird.
Bender: What did the doctor say?
Sol: Is he sick?
Alicia: I don't know. I want to see what John's been working on.
Sol: Alicia, you know you can't go in his office.
Bender: You know it's classified, Alicia.
[Alicia keeps going]
Bender: Stop!
[as Bender tries to stop her, she turns around and slaps him]
Charles: It's not my problem and it's not your problem. It's their problem. Your answers are not on that wall. They're out there, where you've *been* working.
Nash: You wanted to see if I was crazy and would screw everything up if I actually won.
Charles: The prodigal roommate arrives.
Bender: Go With God!
Sol: Come back a man!
Bender: Fortune favors the brave!
Alicia: Who are you talking too?
Nash: The Garbageman
Alicia: Garbagemen don't come at night.
Nash: [Hearing the Garbageman outside] Guess around here, they do.
Charles: When's the last time you ate? You know... food.
Parcher: Conviction, it turns out, is a luxury of those on the sidelines, Mr. Nash.
Hansen: Cowards, all of you. Come on. Whoever wins, Sol does his laundry for the semester.
Sol: Does that seem unfair to anybody?
Bender: No, not at all.
Bender: Hey, look, you made the cover of Fortune... again...