The sense in which this is true is similar to what they mean when they say that a car engine mechanic “knows everything there is to know about car engines.” Sur

The sense in which this is true is similar to what they mean when they say that a car engine mechanic “knows everything there is to know about car engines.” Sure, conceivably you could do with a car engine something that it is not designed for and which would be beyond what the mechanic would know or expect, or you could (unlikely) invent a new material (a “number” system for matrix elements) which would lead to results that are hard to predict in advance, but the “engine science” itself would hardly benefit from such things...