Full Idea
Space and time are the two intuitions on which pure mathematics grounds all its cognitions and judgements that present themselves as at once apodictic and necessary.
Clarification
'apodictic' means demonstrable
Gist of Idea
All necessary mathematical judgements are based on intuitions of space and time
Source
Immanuel Kant (Prolegomena to Any Future Metaphysic [1781], 284)
Book Reference
Kant,Immanuel: 'Prolegomena to Any Future Metaphysic', ed/tr. Lucas,Peter G. [Manchester UP 1971], p.39
A Reaction
This unlikely proposal seems to be based on the idea that mathematics must arise from the basic categories of our intuition, and these two are the best candidates he can find. I would say that high-level generality is the basis of mathematics.