The eye is not possessed of sight; neither is colour a property of matter, or it must be indestructible by fire and every other means. The senses should be considered as but mechanical agents for exciting the brain; by which means it is we have our knowledge, the particulars of the whole of which are mental, confined to the brain, and consist, solely, in the cerebral excited scenery of the sensorium. We have no other kind or means of acquiring knowledge, that is, mental information. By the mere organs of sense we know nothing. The knowledge we have by means of the senses exciting the brain, consists in sensations or sensible effects, and, _we know nothing but our knowledge_, whatever may be thought of externals being objects and immediate objects of our knowledge. In describing what we know, it is imagined the description is of external bodies, their appearance, qualities, and properties; which, however harmless the mistake throughout busy-life affairs,--as all abide, judge, and are directed by the same kind of evidence,--not so is it in philosophy, which is a description of nature's own mode of procedure; and although it is impossible to describe invisible things, as they are really, they should not be philosophised and reasoned on, _as they are not_; they are not according to what we know, and can have no resemblance in any manner to sensations, which are all we know by means of them. Instead of knowing by the senses what bodies are, we know only what they _are not_; modern philosophy is regardless, totally heedless of this most instructive most pointedly directing information, instead of making the just allowance for mental appearances, it materializes every sensation, and imputes the whole to the bodies outside of our own, of which all we can possibly know is but inferential knowledge: it considers our sensations as being qualities of bodies or properties of matter, and maintains that some are physical causes by which certain physical effects are produced. Such may be considered some of the principal reasons why _clairvoyance_ is unintelligible to all the most learned; and so must it ever remain, or until a truer philosophy arises and rescues the great subject from the darkness and errors of a perverting philosophy, the whole of which has to be abandoned before the mind is fitted for the reception of natural truths. We must cease to identify sensations with their unseen, unknown, and but _promoting_, material causes. In proof of the foregoing, a short review of the senses, their physiology, function, result of the function and use of the result, must prove satisfactory and convincing.