I know it's not the main point of this thread, but I actually disagree with House's quote in the title, "Everybody lies". Or at least, I disagree that it's something people can know. The phrase makes an assumption that every single person has made a specific voluntary action before that it's entirely possible for someone to not make.
In order to prove that everyone lies, you'd have to keep track of every single person's life and make a checklist that you mark off for each person when you discover a lie.
And, even if you were able to do all that and prove it, there are still two other details to consider.
1) Just because everyone in the present has done it doesn't mean it's impossible to not do it and that someone in the future won't accomplish it. Like I said, lying is a voluntary action. There are also a lot of people that hate lying.
2) New people are born every day, so it would be a constant struggle to keep up.
I didn't mean to derail the thread. I just don't really see how a statement with the word "Everybody" in it can be proven unless it's something like "Everybody breathes".