For many years, I had a job designing electric circuit breakers. I enjoyed the job because I liked to make things work. I was able to draw on various fundamental laws I had learned in physics and mathematics and put them into practice in a design.
I would test my solution, hoping the test would prove me right.
The design had to be tested and had to pass all tests before it could be considered finished. The tests were reassuring in that they always provided proof of whether the design was correct or not. Successful tests demonstrated the correctness of the principles used and of one's understanding of them.
