And the essence of P&T magic is that, even when you know that, it won't help you.
This clip accompanies a Wired article about the connection between magic (both sleight-of-hand and stage) and the neurology and psychology of perception.
If your browser won't display the embedded version, click here.
The article is fascinating on its own merits. The significance of the photo at the top of the page--hint: it isn't a double-exposure--will become apparent if you read far enough.
Hat tip to James the Elder.