MIBEOKS AND MODES OF VISION. 53 



tion or experience that it acquires no new or improved 

 mode of mirroring by use he could not have fallen into 

 this error. He might have been correct had it been true 

 that the objects presented by a mirror are seen on the flat 

 surface of the mirror, for then a mirrored image would 

 have been a flat picture ; but we do not see reflected 

 images on the surface of the mirror by which they are 

 reflected ; for the eye, or the Consciousness as our per- 

 ceptive power, has no physical contact whatever with that 

 surface. We perceive them only by the incident rays 

 which are reflected or thrown off from the flat surface of 

 the mirror after being intercepted by it. We perceive 

 them, in fact, just as if there had been no mirror whatever, 

 but merely as if the direction of the original rays 

 proceeding from the objects themselves had been changed ; 

 for a mirror does not serve the purpose of flattening and 

 localising a picture of the objects it is said to represent ; 

 it merely alters the direction of the rays from the objects 

 themselves. And the question comes to be one of the 

 very greatest difficulty whether we perceive the images 

 on the retina in any other way whether the Conscious- 

 ness is in actual contact with the concave surface of the 

 retina, or whether the rays of light are reflected from 

 that concave surface to the Consciousness seated to receive 

 them elsewhere. To solve such a question, it must be 

 admitted, is no ordinary labour of thought. We shall 

 endeavour to approach it by divesting it of its inessen- 

 tialities of those associated circumstances which are not 

 elements of the question. The first of these is the point 

 whether the Consciousness is seated in the retina or seated 

 elsewhere. Now it matters not whether it is or is not 

 seated elsewhere, for there can be no doubt, wherever it is 

 situated, that the imaging rays are the means by which it 

 perceives the appearances of objects. It is not the retina 

 which Consciousness perceives, but the imaging light, for 



