Carl Gustav Jung, R.F.C. Hull (Translator)

Now if we conceive numbers as having been discovered, and not merely invented as an instrument for counting, then on account of their mythological nature they belong to the realm of 'godlike' human and animal figures and are just as archetypal as they. Unlike these, however, they are 'real' in the sense that they are encountered in the realm of experience as quantities and thus form the bridge between the tangible, physical world and the imaginary. Though the latter is unreal, it is 'real' in so far as it works; i.e., has an effect on us.