how can I tell what's real?

House: How can I tell what’s real and what’s not?
Everything looks the same, sounds the same, tastes the same.

Jack: Seems like I’d be the last person you’d want to ask.

House: Why not? You’re obviously not here. I’m obviously not here. Which means this is a creation of my mind. Which means I’m really just asking myself.

Jack: ‘You’re talking to yourself thats a lot of unnecessary explanation.

House: Hey, I’m trying to work this out. That requires give and take, even in my own mind.

Jack: Alright. What was the question?

House: How can I tell what’s real?

Jack: Does it matter?

House: That doesn’t sound like something I’d ask.

Jack: Alright. Your concern is that if you act in the real world based on information that’s not real, the results are impossible to forsee.

House:—With you so far..

Jack: But information is incapable of harm in and of itself.
Ideas are neither good nor bad, but merely as useful as what we do with them. Only actions can cause harm.

House: That sounds like me.