[21] For it is not natural to suppose that the subject of judgment can possibly be comprehended without some power which is to judge; and the power which judges of the objects of the external sense is the external sense, so that without the external sense it would not be possible for any thing in that world which is perceptible by the external sense to be accurately known, though those are the matters which are the principal field for philosophical speculation. But the external sense, being that portion of the soul which most resembles the body, is deeply rooted in the entire vessel of the soul; and the vessel of the soul is, by a figurative way of speaking, called Egypt.