A mathematician, a physicist and an engineer are given an
identical problem: Prove that all odd numbers greater than
2 are prime numbers. They proceed:
Mathematician: 3 is a prime, 5 is a prime, 7 is a prime,
9 is not a prime - counterexample - claim is false.
Physicist: 3 is a prime, 5 is a prime, 7 is a prime,
9 is an experimental error, 11 is a prime, ...
Engineer: 3 is a prime, 5 is a prime, 7 is a prime,
9 is a prime, 11 is a prime, ...