MAN AS THE INTERPRETER OF NATURE. 695 



form, which we derive from the visual sense alone, is so complete that 

 we seldom require to fall back upon the touch for any further informa- 

 tion respecting that quality of the object. So, again, while it is from 

 the coordination of the two dissimilar pictures formed by any solid or 

 projecting object upon our two retinae that (as Sir Charles Wheat- 

 stone's admirable investigations have shown) we ordinarily derive 

 through the sight alone a correct notion of its solid form, there is 

 adequate evidence that this notion also is a mental judgment based on 

 the experience we have acquired in early infancy by the consentaneous 

 exercise of the visual and tactile senses. 



Take, again, the case of those wonderful instruments by which 

 our visual range is extended almost into the infinity of space or into 

 the infinity of minuteness. It is the mental, not the bodily, eye that 

 takes cognizance of what the telescope and the microscope reveal 

 to us. For, we should have no well-grounded confidence in their 

 revelations as to the unknown, if we had not first acquired experience 

 in distinguishing the true from the false by applying them to known 

 objects ; and every interpretation of what we see through their instru- 

 mentality is a mental judgment as to the probable form, size, and 

 movement of bodies removed by either their distance or their minute- 

 ness from being cognosced by our sense of touch. 



The case is still stronger in regard to that last addition to our 

 scientific armamentum which promises to be not inferior in value 

 either to the telescope or the microscope ; for it may be truly said of 

 the spectroscope that it has not merely extended the range of our 

 vision, but has almost given us a new sense by enabling us to recog- 

 nize distinctive properties in the chemical elements which were pre- 

 viously quite unknown. And who shall now say that we know all 

 that is to be known as to any form of matter, or that the science of 

 the fourth quarter of this century may not furnish us with as great 

 an enlargement of our knowledge of its properties, and of our power 

 of recognizing them, as that of its third has done ? 



But, it may be said, Is not this view of the material universe open 

 to the imputation that it is " evolved out of the depths of our own 

 consciousness " a projection of our own intellect into what surrounds 

 us an ideal rather than a real world ? If all we know of matter be 

 an " intellectual conception," how are we to distinguish this from such 

 as we form in our dreams, for these, as our Laureate no less happily 

 than philosophically expresses it, are " true while they last." Here 

 our " common-sense " comes to the rescue. We " awake, and behold it 

 was a dream." Every healthy mind is conscious of the difference 

 between his waking and his dreaming experiences, or, if he is now and 

 then puzzled to answer the question, " Did this really happen or did I 

 dream it ? " the perplexity arises from the consciousness that it might 

 have happened. And every healthy mind, finding its own experi- 

 ences of its waking state not only self-consistent, but consistent with 



