Just as the introduction of the irrational numbers ... is a convenient
myth [which] simplifies the laws of arithmetic ... so physical objects
are postulated entities which round out and simplify our account of the
flux of existence... The conceptional scheme of physical objects is [likewise]
a convenient myth, simpler than the literal truth and yet containing that
literal truth as a scattered part.
In J. Koenderink Solid Shape, Cambridge Mass.: MIT Press, 1990.