In Universal Arithmetick Newton says: "By Number we understand not so much a Multitude of Unities, as the abstracted Ratio of any Quantity, to another Quantity of the same Kind, which we take for Unity. "
What am I to understand by the word "abstracted"?
I mean something like this: points and lines are said to be abstracted from dots, pebbles, sticks, sunbeams, etc. Multitudes of unities from multitudes of things, herds of cows, stacks of coins, etc. But how is a ratio an abstraction at all?