But it must not be forgotten that ... glass and porcelain were manufactured, stuffs dyed and metals separated from their ores by mere empirical processes of art, and without the guidance of correct scientific principles.

I shall certainly admit a system as empirical or scientific only if it is capable of being tested by experience. ... It must be possible for an empirical scientific system to be refuted by experience. (1959)

While electric railroading is perhaps the most important branch of electrical engineering, at least as regards commercial importance, considering the amount capital invested therein, nevertheless it is a remarkable fact that while most other branches of electrical engineering had been developed to a very high degree of perfection, even a few years ago theoretical investigation of electric railroading was still conspicuous by its almost entire absence.
All the work was done by some kind of empirical experimenting, that is, some kind of motor was fitted up with some gearing or some sort of railway car, and then run, and if the motor burned out frequently it was replaced with a larger motor, and if it did not burn out, a trailer was put on the car, and perhaps a second trailer, until the increase of the expense account in burn-outs of the motors balanced the increased carrying capacity of the train.