Full Idea
We need 'unities' in order to be able to reckon: that does not mean we must suppose that such unities exist.
Gist of Idea
We need 'unities' for reckoning, but that does not mean they exist
Source
Friedrich Nietzsche (The Will to Power (notebooks) [1888], §635)
Book Reference
Nietzsche,Friedrich: 'The Will to Power', ed/tr. Kaufmann,W /Hollingdate,R [Vintage 1968], p.338
A Reaction
True. I takes this thought to be important in the Psychology of Metaphysics (an unfashionable branch).