Me and my teacher have been debating about the concept of distance. While he says that the length of a curve is something that is something that is not abstract, I say that this is false. Distance only applies to lines, the definition of a length of a curve is mearly the limit of the sums of several lines as the we choose the interval to be smaller and smaller. To me, the concept dosen't mean anything unless we give it a purely abstract meaning. Who has the right view?