[143] For as the eyes see, and still the mind sees more clearly by means of the eyes; and as the ears hear, but nevertheless the mind hears better through the medium of the ears; and as the nostrils smell, and yet the soul smells more precisely through the instrumentality of the nostrils; and in like manner, as the other external senses comprehend their respective appropriate objects, still the mind comprehends them also more purely and distinctly by their ministration. For to speak properly, it is the mind which is the eye of eyes, the hearing of hearing, and the more pure external sense of each of the external senses, using them as ministers in a court of justice, and itself deciding on the nature of the objects submitted to it, so as to approve of some and to reject others. In the same way, those that are called the intermediate arts, resembling the faculties of the body, indulge in contemplations according to certain simple observations of them, but the sciences do so with greater accuracy and with an exceedingly careful investigation.