THE PBOBLEM OF CONSCIOUSNESS. 299 



of consciousness until we can renew it with much larger resources of 

 knowledge. 



The psychologists ought now to apply the comparative method on a 

 grand scale. They are just beginning to use it. Years of patient labor 

 must pass by, but the reward will be very great. The psychic life of 

 animals must be minutely observed, the conditions of observation care- 

 fully regulated and the results recorded item by item. The time has 

 passed by for making generalizations on the basis of our common, 

 vague and often inexact notions concerning the habits of animals. 

 Exact experimental evidence will furnish a rich crop of psychological 

 discovery. Scientific psychology is the most backward in its develop- 

 ment of all the great divisions of biology. It needs, however, little 

 courage to prophesy that it will bring forth results of momentous im- 

 portance to mankind. After data have been gathered, generalization 

 will follow which, it may be hoped, will lead us on to the understanding 

 of even consciousness itself. 



The teleological impress is stamped on all life. Vital functions 

 have a purpose. The purpose is always the maintenance of the indi- 

 vidual or of the race in its environment. The entire evolution of 

 plants and animals is essentially the evolution of the means of adjust- 

 ment of the organism to external conditions. According to the views 

 I have laid before you, consciousness is a conspicuous, a commanding, 

 factor of adjustment in animals. Its superiority is so great that it has 

 been, so to speak, eagerly seized upon by natural selection and pro- 

 vided with constantly improved instruments to work with. A con- 

 crete illustration will render the conception clearer. In the lowest 

 animals, the ccelenterates, in which we can recognize sense organs, the 

 structure of them is very simple, and they serve as organs of touch 

 and of chemical sensation resembling taste. In certain jelly fishes we 

 find added special organs of orientation and pigmented spots for the 

 perception of light. In worms we have true eyes and vision. In ver- 

 tebrates we encounter true sense of smell. Fishes cannot hear, but in 

 the higher vertebrates, that is from the amphibians up, there are true 

 auditory organs. In short, both the senses once evolved are improved 

 and also new senses are added. It is perfectly conceivable that there 

 should be yet other senses, radically different from any we know. An- 

 other illustration, and equally forcible, of the evolution of aids to con- 

 sciousness might be drawn from the comparative history of the motor 

 systems, passing from the simple contractile thread to the striated mus- 

 cle fiber, from the primitive diffuse musculature of a hydroid to the 

 highly specialized and correlated muscles of a mammal. 



It is interesting to consider the evolution of adjustment to external 

 reality in its broadest features. In the lowest animals the range of the 

 possible adjustment is very limited. In them not only is the variety 



