There have been a few threads on here recently about fooling or impressing other magicians. So, I thought I'd share my ideas on the subject.
First, it's important to have a clear understanding of what exactly is happening when someone is fooled or amazed by a magic effect. Here's the basic anatomy of a magical effect:
1. A logical sequence of actions is established.
2. This sequence leads inevitably to one easily-predicted outcome.
3. Without apparently diverging from that sequence, a different outcome occurs.
For example:
1. A coin is examined, placed in the performer's left hand, and that hand is closed into a fist.
2. It's made obvious that nothing could have got in or out of that hand, so, inevitably, the coin must still be there.
3. The performer opens their hand and the coin has vanished.
Now, as magicians without real supernatural powers, we're going to have to cheat somewhere along the line. We can cheat at step 1 by, perhaps, not really placing the coin into our left hand and only pretending to. We could cheat at step 2 by, perhaps, using some gimmick which can remove the coin from an apparently closed hand. We could even cheat at step 3 by, perhaps, clipping the coin in such a way that it appears to have vanished but is actually still held by the hand.
The strongest magic tricks have the cheat at the most psychologically and visually invisible point. And that, in my opinion, is step 2. The reason for this is that step 2 happens entirely in the mind of the spectator. As soon as the spectator is convinced that they understand the logical sequence that is taking place then they skip to the end.
If I point at something, you don't look at my finger and then gradually follow its line until you reach the object that I'm pointing at. You see the direction of my finger and look straight at the object. If we set up a logical sequence which points inevitably towards one conclusion, then our spectator leaps directly to that conclusion. As long as our actions are motivated and justified by the logical sequence we've set up, then magic can happen.
All we need to do, then, to fool magicians is to recognise that certain sequences of actions that seem to logically point one way to laypeople, point a different way to magicians. And that's because the elements in that sequence signal different things. Laypeople see the deck being squared, magicians see a pass. Laypeople see a wallet, magicians see a loading device. Laypeople see a paper ball vanish, magicians look behind them.
So, fooling magicians is exactly the same as fooling anyone else. We just need to understand what logical sequence we're establishing, and therefore what conclusion we're pushing them towards. If a magician sees me do a retention pass with a coin, then go into my pocket for a pen to use as wand, then they will conclude that I've just ditched the coin in my pocket. If I open my hand to show the coin still there then that's a magical moment. To a lay audience, that's a moment of nothing.
My conclusion is this. Fooling any audience is about understanding what prior knowledge, expectations and preconceptions they are bringing with them. Then you work with that information and guide them towards the knowledge, expectation and preconceptions you want them to have. You build from that foundation to set up a clear logical sequence which can have only one possible end point. When that end point is established in the audience's mind, you secretly subvert the logical sequence to alter the conclusion. If you do that, you can fool anyone!