296 POPULAR SCIENCE MONTHLY. 



cerning our surroundings, which we utilize for our teleological needs, 

 although in nature external to us there is no sound at all. Similarly 

 all our other senses report to us circumstances and conditions, but 

 always the report is unlike the external reality. Our sensations are 

 symbols merely, not images. They are, however, bionomically sufficient 

 because they are constant. They are useful not because they copy the 

 external reality or represent it, but because, being constant results of 

 external causes, they enable consciousness to prophesy or foresee the 

 results of the reactions of the organism, and to maintain and improve 

 the continual adjustment to the external reality. 



The metaphysicians have for centuries debated whether there is 

 any external objective reality. Is it too much to say that the biological 

 study of consciousness settles the debate in favor of the view that the 

 objective world is real ? 



Consciousness is not only screened from the objective world from 

 which it receives all its sensations, but also equally from immediate 

 knowledge of the body through which it acts. As I write this sentence 

 I utilize vaso-motor nerves, regulating the cerebral blood currents, and 

 other nerves which make my hand muscles contract and relax, but of 

 all this physiological work my consciousness knows nothing though it 

 commands the work to be done. The contents of consciousness are as 

 unlike what is borne out from it as they are unlike what is borne in 

 to it. 



The peculiar untruthfulness to the objective which consciousness 

 exhibits in what it gets and gives would be perplexing were it not that 

 we have learned to recognize in consciousness a device to secure better 

 adjustment to external reality. For this service the system of symbols 

 is successful, and we have no ground for supposing that the service 

 would be better if consciousness possessed direct images or copies in- 

 stead of symbols of the objective world. 



Our sensory and motor* organs are the servants of consciousness; 

 its messengers or scouts; its agents or laborers; and the nervous sys- 

 tem is its administrative office. A large part of our anatomical char- 

 acteristics exists for the purpose of increasing the resources of conscious- 

 ness, so that it may do its bionomic function with greater efficiency. 

 Our eyes, ears, taste, etc., are valuable, because they supply conscious- 

 ness with data; our nerves, muscles, bones, etc., are valuable, because 

 they enable consciousness to effect the needed reactions. 



Let us now turn our attention to the problem of consciousness in 

 animals. The comparative method has an importance in biology which 

 it has in no other science, for life exists in many forms which we com- 

 monly call species. Species, as I once heard it stated, differ from one 



* And other organs in efferent relations to consciousness. 



