> Let's start: > > 1. A magnitude is the idea of size of extent.
Is magnitude a mathematical thing? Because if so I would hesitate to define it as an idea of any kind. Mathematical thing seem to have a life of their own: so if I add the "ideas" 2 and 3 I get the "idea" 5, and so do you. How is that possible? Then there is Wigner's "unreasonable effectiveness of mathematics in the natural sciences". Whatever mathematical things are (and don't ask me, I haven't a clue) they seem to be rather more than just ideas.
-- Madam Life's a piece in bloom, Death goes dogging everywhere: She's the tenant of the room, He's the ruffian on the stair.