Several students were asked to prove that all odd integers are prime.
The first student to try to do this was a math student. "Hmmm...
Well, 1 is prime, 3 is prime, 5 is prime, and by induction, we have that all
the odd integers are prime."
The second student to try was a man of physics who commented, "I'm not
sure of the validity of your proof, but I think I'll try to prove it by
experiment." He continues, "Well, 1 is prime, 3 is prime, 5 is prime, 7 is
prime, 9 is... uh, 9 is... uh, 9 is an experimental error, 11 is prime, 13
is prime... Well, it seems that you're right."
The third student to try it was the engineering student, who responded,
"Well, to be honest, actually, I'm not sure of your answer either. Let's
see... 1 is prime, 3 is prime, 5 is prime, 7 is prime, 9 is... uh, 9 is...
well, if you approximate, 9 is prime, 11 is prime, 13 is prime... Well, it
does seem right."
Not to be outdone, the computer science student comes along and says
"Well, you two sort've got the right idea, but you'll end up taking too long!
I've just whipped up a program to REALLY go and prove it." He goes over to
his terminal and runs his program. Reading the output on the screen he says,
"1 is prime, 1 is prime, 1 is prime, 1 is prime..."
