Page:Letters on the Human Body (John Clowes).djvu/48

28 of that part of your constitution which you call rational and intelligent, and how it is the continual result of the transplantation (if I may so express myself), through the medium of external vision, of all the visible objects of creation in this lower world, into the interior recesses of mental power and operation. You forget, therefore, that thought, reason, intellect, &c., owe their birth, in a great measure, to the stores of material images introduced by such transplantation, since without those images, there would be a deficiency of the ideas necessary to constitute a thinking, rational, and intellectual mind.

But, on this occasion, a caution may be requisite, to guard you against the error, into which some modern philosophers and metaphysicians have been betrayed, whilst, in opposition to all the rules and maxims of sound philosophy, they have ascribed to external material substances the power of insinuating themselves into the mind through the organ of vision; and have thus invested those substances with an ability which doth not, and cannot, belong to them. For what eye cannot see, that matter, howsoever it may be modified and organized, is in itself dead; and, consequently, is utterly incapable, of itself, to enter into mind, so as to form images there? What eye, therefore, cannot see further, especially if under the illumination of heavenly