Not the Spice Girls' hit.
How often have you heard "Omigod I wish I was ----!" where the person might be the latest reality TV star, pop idol or maybe someone more eminently substantial, or at least rich and famous?
It's always struck me there's a touch of paradox about this wish, taking it seriously (as I imagine the utterers seldom do).
Let's call the wisher Courtney, and the person they would like to be - say - Madonna. As Courtney isn't currently Madonna, how do they differ as people? Let me suggest in five possible ways:
1. Intelligence (IQ).
2. Personality (say the 'Five-Factor Model').
3. Mental state (memories, beliefs, objectives, etc).
5. Physical traits (height, weight, etc).
Now we do a thought-experiment. An alien with incredibly advanced technology kidnaps Courtney and puts her into a special device which does human transmutation.
"Well, Courtney," says the alien, "who would you like to be?"
"Madonna," breathes Courtney in a husky, wannabe voice.
"Okeydokey ..." says the alien, and starts adjusting the knobs.
*1. The IQ knob is adjusted substantially up.
*2. The personality knob is adjusted for:
-- increased extraversion,
-- decreased agreeableness,
-- increased openness to experience,
-- increased conscientiousness,
-- decreased neuroticism.
(You understand I have a private model in my head for dear young Courtney).
*3. Courtney's memories of her life to-date are expunged and replaced by precise copies of those in Madonna's head right now; ditto for beliefs, objectives.
*4. Gender matches already so no need for surgery there.
*5. The alien now adds a lot more muscle and removes a great deal of flab.
"OK, done," says the alien. "How are you feeling, Madonna?"
"I want my agent right here right now!" she snaps, "and my lawyer!"
You see the problem? Courtney was a Madonna wannabe, and her wish came true and so she became Madonna.
Of course Madonna already exists, so in a sense Courtney's desire has already come true.
Perhaps I should ram the point home. You can be a wannabe, and if your wish came true you would cease to exist and simply be your hero or heroine. Since they already exist, all that remains therefore is to terminate your own existence.
You don't need the alien.
But you won't, will you, Courtney?
I wrote a similar piece some time ago (here) asking the question: 'How many people are there on the Earth today who are psychologically identical to you?" Identical means points 1, 2 and 4 above: IQ, personality and gender.