Full Idea
There is so intimate a connection between the concepts of addition and of quantity that one cannot begin to grasp the latter without the former.
Gist of Idea
Quantity is inconceivable without the idea of addition
Source
Gottlob Frege (Rechnungsmethoden (dissertation) [1874], p.2), quoted by Michael Dummett - Frege philosophy of mathematics 22 'Quantit'
Book Reference
Dummett,Michael: 'Frege: philosophy of mathematics' [Duckworth 1991], p.279
A Reaction
Frege offers good reasons for making cardinals prior to ordinals, though plenty of people disagree.
Related Idea
Idea 18255 Addition of quantities is prior to ordering, as shown in cyclic domains like angles [Dummett]