Do I exist?

Sometimes I get into interesting conversations with my children, like this afternoon. While driving home from a store, we passed by an area where something was being constructed, a bridge or something. My daughter asked, "What's that?" To which I replied, "I don't know." And she said, "But I thought you know everything?" To which I said, "I do." And she gave me a funny look, so I further added, "So that's obviously nothing, or I would know what it is."

This spawned a conversation about existence, as she said, "Obviously it is something." And I said, "No, it's not." And she said, "But it was there! It exists!" I asked her what it means to "exist."

"Um..." She tried to define existence as "being there" - well, I'm not there (obviously, since I'm here), thus I must not exist, since I'm not there.

"Ok, something exists if you can see it." Well, you can't see air, so air must not exist. And how many people see various illusions, such as the "water on the road up ahead" on a hot day that turns out not to be there? I'd say that simply seeing something doesn't define its existence.

"Ok, if it's made of matter, it exists." Light isn't made of matter; radio waves aren't made of matter; thus, they must not exist.

"Look, if we go back there, I can touch it, and prove it exists!" Perhaps; but you don't know that it exists. "Yes, I do!" No, you don't; you think it exists; you believe it exists; you have faith that it exists; but you don't actually know if it exists (since seeing doesn't necessarily imply existence).

In fact, think about the matrix for a moment: the "bad guy" in the first Matrix movie talks about his "steak" - the steak that really is only a set of electrical impulses fed to his nerves and brain to make him think he's eating a steak. The steak doesn't exist, but it feels, tastes, and looks real to him since his senses have told him it's there, it's good, enjoy! Similarly, your senses could be fooled (e.g., the aforementioned optical illusion that causes you to think something does exist - like the "water" on the road on a hot day; or doesn't exist, like when David Coperfield made the Statue of Liberty disappear - see the video below).



I love the old lady's comment: "I have never seen a Statue of Liberty disappear the way this one did!"

According to Merriam-Webster OnLine, "exist" means (first definition seems most pertinent to this discussion):

1 a: to have real being whether material or spiritual <did unicorns exist> <the largest galaxy known to exist> b: to have being in a specified place or with respect to understood limitations or conditions <strange ideas existed in his mind>

Anyway, that's my deep thought of the night: do I exist, or am I a figment of your imagination? Do you exist? Apparently not, as I never seem to have any comments on this blog... :)