To measure is to know.
When you are face to face with a difficulty, you are up against a discovery.
I have no satisfaction in formulas unless I feel their numerical magnitude.
Quaternions came from Hamilton after his really good work had been done, and though beautifully ingenious, have been an unmixed evil to those who have touched them in any way.
You know only insofar as you can measure.
Symmetrical equations are good in their place, but ' vector ' is a useless survival, or offshoot from quaternions, and has never been of the slightest use to any creature.