Keep Laughing (problem of 2*2)

An assemblage of the most gifted minds in the world were all posed the following question:
"What is 2 * 2 ?"

The chemist says immediately around 10 to the power 1.
The engineer whips out his slide rule and shuffles it back and forth, and finally announces "3.99".
The physicist consults his technical references, sets up the problem on his computer, and announces "it lies between 3.98 and 4.02".
The mathematician cogitates for a while, oblivious to the rest of the world, then announces: "I don't what the answer is, but I can tell you, an answer exists!".
Philosopher: "But what do you mean by 2 * 2 ?"
Logician: "Please define 2 * 2 more precisely."
Accountant: Closes all the doors and windows, looks around carefully, then asks "What do you want the answer to be?"
Computer Hacker: Breaks into the NSA super-computer and gives the answer.
Stress engineer: Well I know it's 4, but let's call it 50 anyway.......
The psychologist: Why do you wish to know that?
The sociologist: I don't know, but is was nice talking about it.

The Doctor : 4

All others looking astonished : How did you know ??

The Doctor : I memorized it... :)