"The only thing I know is that I'm not here." - Schrödinger's Cat
"I'm a cat, but not really. Maybe I'm a box of cat food. Maybe I'm a thought experiment." - Schrödinger's Cat
Schrödinger's Cat says...
Visit qbit-quantum-fluctuation for more existential dread.
Or, if you're feeling particularly philosophical, check out many-worlds-interpretation.