508 INTELLECTUAL SYMBOLISM. 
sensations to the brain. If I press upon the ball of my eye, the optic nerve will convey 
the impression of light to which it is adapted. If the bloodvessels of the head are un- 
naturally distended, so as to compress the auditory nerve, that nerve will also convey the 
only impression of which it is susceptible, that of sound. There can be no possible doubt 
of the reality of the impressions or sensations, but there may be a doubt as to the cause 
of those sensations. If the judgment is made hastily, and without due regard to all the 
circumstances which ought to be taken into consideration, it will probably be erroneous. 
184. The healthy optic nerve not only perceives the rays of light, but also the direction 
in which they come. The mind perceives that distant objects are more indistinct than 
those that are nearer. Therefore, if anything is seen which subtends a small angle, but is 
very indistinct, we may naturally suppose that it is a large object ; whereas, if it had been 
perfectly distinct and subtended the same angle, we should have judged it to be very 
small. Our judgments formed in this manner may be generally correct, but they will not 
be infallible, unless the cause of the indistinctness is perfectly understood. 
185. If we could conceive that any object at which we were looking actually touched 
the eye, we should think it exceedingly diminutive. If we supposed it to be within the 
eye, at the intersecting point of the rays from the top and base, it would seem to be a 
mere point ; and if we could possibly fancy that it was near the retina, we should believe 
that it was reversed.* There are, therefore, various ways in which a judgment, based 
either on the evidence of our senses, or on mathematical axioms, or on propositions de- 
monstrably true, may be deceptive, but in every instance our error will be found to arise 
from a partial or improper use of some of our faculties.t 
186. All deception is a virtual lie. 
187. If I place in the hands of a pupil a book in which the words are so far perverted 
from their usual meaning that he cannot fail of receiving a false impression, and if, al- 
* Prof. Liedenfrost’s case of the young man who first received his sight when he reached his seventeenth year, 
and to whom all objects at first seemed inverted, can be easily explained on this principle. See Wayland, p. 76. 
+ A great deal of needless obscurity has been thrown by some writers about the subjects of erect and binocular 
vision. If we looked merely at the images on the retina, we could not fail of seeing two images, both inverted. 
But the simple hypothesis that we look at the objects themselves, and that the eye informs us correctly of the 
direction of the luminous rays that proceed from all parts of the object, is not only entirely consistent, but it re- 
moves all difficulty. Then, if our judgment fixes the relative position of the object accurately, its size, outline, 
and solidity will be determined with mathematical precision. 
It would be well for philosophy to get rid of the idea of images, as entities distinct from the objects themselves. 
Whether the rays of light come to the eye from a reflecting, or through a refracting medium, they come from the 
object that is seen; and it is as proper for us to say that we see ourselves in a mirror, as to say that we see a star 
through a telescope, a stone under water, or a cloud in the air. In each case the rays of light are diverted from 
a direct course, and it is the office of judgment to determine the extent and cause of the diversion. 
