Catherine: It doesn't fit me.
[about the dress]
Hal: Sure it does.
Catherine: You can't prove it.
Hal: I can disprove the opposite.
Catherine: It is forty pages long. I didn't memorize it. It is not a muffin recipe!
Catherine: [Reading Robert's Notebook] "Let X equal the quantity of all quantities of X. Let X equal the cold. It is cold in December. The months of cold equal November through February. There are four months of cold, and four of heat, leaving four months of indeterminate temperature. In February it snows. In March the Lake is a lake of ice. In September the students come back and the bookstores are full. Let X equal the month of full bookstores. The number of books approaches infinity as the number of months of cold approaches four. I will never be as cold now as I will in the future. The future of cold is infinite. The future of heat is the future of cold. The bookstores are infinite and so are never full except in September..."
Catherine: Do you want to go?
Hal: I want to stay here with you.
Hal: I want to spend the day with you, if at all possible, I want to spend as much time with you as I can, unless I'm coming on way too strong right now and scaring you, in which case I'll begin back-pedalling immediately!
Claire: Did you use that conditioner I brought you?
Catherine: No. Shit. I forgot.
Claire: Well, it's my favorite. You'll love it, Katie. I want you to try it.
Catherine: I'll try it next time.
Claire: You'll like it. It has jojoba.
Catherine: What is jojoba?
Claire: It's something they put in for healthy hair.
Catherine: Hair is dead.
Catherine: It's... It's dead tissue. You can't make it healthy.
Claire: Whatever. It's good for your hair.
Catherine: Like what? A chemical?
Claire: No. It's organic.
Catherine: It can be organic and still be a chemical.
Claire: I don't know what it is.
Catherine: Heard of organic chemistry?
Claire: It makes my hair look, smell and feel good, and that is the extent of my information about it. You might like it if you decide to use it.
Catherine: Thanks. I'll try it.
Catherine: [voice over] How many days have I lost? How can I get back to the place where I started? I'm outside a house, trying to find my way in. But it is locked and the blinds are down, and I've lost the key, and I can't remember what the rooms look like or where I put anything. And if I dare go in inside, I wonder... will I ever be able to find my way out?
[Catherine looks up; Hal is standing in front of her]
Catherine: Sometimes in my head I think it works, and then... Sometimes I just think it's crazy.
Hal: There's nothing wrong with you.
Catherine: I think I'm like my dad.
Hal: I think you are, too.
Catherine: I'm afraid I'm like my dad.
Hal: You are not him.
Catherine: Maybe I will be.
Hal: Maybe, and maybe you'll be better.
Catherine: It was like... connecting the dots. Some nights I could connect three or four of them, and some nights they'd be really far apart. I'd have no idea how to get to the next one, if there was the next one. It just seems really stitched together and lumpy. Dad's stuff was way more elegant.
Hal: Talk me through it and tell me what's bothering you.
Catherine: [voice over] If I go back to the beginning, I could start it over again. I could go line by line, try and find a shorter way. I could try to make it... better.
Hal: You read a lot of maths.
Catherine: I read Cosmo. It is just a window dressing.
Catherine: It is thirty degrees outside, in the middle of the night. Are you cold?
Robert: Of course, I am freezing my ass off
Catherine: She was born in Paris in 1776.
Hal: Then I definitely never met her.
Catherine: I didn't find it.
Hal: Yes, you did.
Catherine: No, I didn't
Hal: I didn't find it.
Catherine: I didn't find it. I wrote it.
Catherine: I feel like I could crack open, like an egg, or one of those really smelly French cheeses that ooze when you cut them.
Catherine: Wow. I can't believe how many people are here. I never knew he had this many friends. Where have you all been for the last five years? I guess to you guys he was already dead, right?
Catherine: You blew it. It's too bad, too, cause the rest of it was really good. "I loved your dad." "I always liked you." "I wanna spend every minute with you." That's killer stuff.
Hal: I meant it.
Catherine: You got laid and you got the notebook. You're a genius.
Hal: Talk to me, Catherine. This proof is yours.
Robert: What about Claire?
Catherine: She's not my friend. She's my sister.
Hal: It's too advanced. I don't even understand most of it.
Catherine: You think it's too advanced?
Catherine: It's too advanced for you.
Hal: You could not have done this work.
Catherine: But what if I did?
Hal: Well, what if?
Catherine: It would be a real disaster for you. Wouldn't it? You and the other geeks who barely finished their PhD's, who are marking time doing lame research, bragging about the conferences they go to. Wow. Playing in an awful band and whining that they're intellectually past it at 26, because they are!
Robert: What's the matter?
Catherine: It doesn't make sense.
Robert: Sure it does.
Robert: Where's the problem?
Catherine: The problem is, you are crazy.
Catherine: So you said a crazy person would never admit that.
Robert: Ah. I see.
Robert: It's a point.
Catherine: So how can you admit it?
Robert: Well because, I'm also dead. Aren't I?
Catherine: If I go back to the beginning, I could start it over again. I could go line by line; try and find a shorter way. I could try to make it... better.
Hal: Well, I'm gonna be late. Some friends of mine are in this band. They're playing in a bar on Diversey, way down the bill, they go on about 2 to 2:30. I said I'd be there.
Hal: They're all in the math deparment, they're really good. They have this song called 'i', you'd like it. Like lower-cased i. They just stand there and don't play anything for three minutes.
Catherine: Imaginary number.
Hal: It's a math joke... You see why they're way down on the bill.
Catherine: That's a long way to drive to see some nerds in a band.
Hal: You know, I hate when people say that. It's not really that long of a drive.
Catherine: So, they are nerds.
Hal: Oh, they're raging geeks. But they're geeks who, you know, can dress themselves and hold down a job at a major university. Some of them have switched from glasses to contacts. They, uh, play sports, they play in a band, they get laid suprisingly often... So, it makes you kinda question the whole set of terms. Geek, nerd, wonk, dilbert, paste eater...
Catherine: You're in this band, aren't you.
Hal: Ok, yes. I play the drums. You wanna come? I never sing, I swear to God.
Robert: I hope you're not spending your birthday alone.
Catherine: I'm not alone.
Robert: I don't count.
Catherine: Why not?
Robert: I'm your old man. Go out with friends.
Catherine: Yeah, right.
Robert: Aren't your friends taking you out?
Robert: Why not?
Catherine: For your friends to take you out, you have to have friends. Funny how that works.
Robert: You're gonna be okay.
Catherine: I am?
Robert: Yes. I promise you. The simple fact that we can talk about this together is a good sign.
Catherine: A good sign?
Catherine: How could it be a good sign?
Robert: Because crazy people don't sit around wondering if they're nuts.
Catherine: They don't?
Robert: No. They've got better things to do. Take it from me. A very good sign that you're crazy is an inability to ask the question, "Am I crazy?"
Catherine: Even if the answer is yes?
Robert: Crazy people don't ask, you see?
Robert: [stirring her out of a dream] Can't sleep?
Catherine: Oh, Jesus! Oh, you scared me.
Professor Bhandari: Mathematics isn't jazz. Even the craziest mathematics is working towards a proof.
Robert: I'm working!
Robert: I mean, I say "I". Machinery. The machinery's working, Catherine. It's on full blast. All the cylinders are firing. I'm on fire.