i Register
In some senses, mathesis is marked as archaic. Watch for register when choosing this word.
noun
Mental calculation or discipline; science, especially mathematical learning.
Forget the Boys, forget your loyalties to your Dead, first of all to Rebekah, for she, they, are but distractions, temporal, flesh, ever attempting to drag the Uranian Devotee back down out of his realm of pure Mathesis, of that which abides.
The science of establishing a systematic order for things. (After Foucault.)
1997, Chris Horrocks, Introducing Foucault, page 69 (Totem Books, Icon Books; →ISBN I’m using 'mathesis' — a universal science of measurement and order […]