REFLEXES, INSTINCT. AND REASON MO 



but sliglit (Icgroe. Tlio discussion as to whether lower animals 

 have minds turns on tlie definition of mind, and our answer to 

 it depends on ihe definition we adopt. 



Most ])hints arc sessile orf^anisms. Kiuh is an or^anie eol- 

 ony of cells, with th(^ power of motion in parts hut not that of 

 locomotion, 'J'he i)lant draws its nourishment from inorganic 

 nature — from air and water. Its life is not conditioned on a 

 search for food, nor on the movement of the hody as a whole. 

 Yet the |)lant searches for food hy a movenjent of the fee<l- 

 ing parts. In the process of growth, as l)arwin has shown, 

 the tips of the branches and roots are in constant motion. This 

 movement is a spiral s(piirm. The movement of the tendrils 

 of the growing vine is only an exaggeration of the same action. 

 The course of the S([uirming rootlet may be deflected from a 

 regular s})iral by the presence of water. The moving branchlets 

 will turn toward the sun. The region of .sensation in the plant 

 and the point of growth are identical because this i,s the only 

 part that needs to move. T\w. tender tip is the plant's l)rain. 

 If locomotion were in question the ))lant would need to Ik* 

 differently constructed. It would demand the mechanism of 

 the animal. The nerve, brain, and muscle of the plant are all 

 represented by the tender growing cells of the moving tijw. 

 The plant is touclied by moisture or sunlight. It may be said, 

 in somewhat metajihorical language, that it "thinks ''of them, 

 and in so doing the cells that are touched and "think" are 

 turned tow-ard the source of the stinuilus. The function of 

 the brain, therefore, in some sense exists in the tree, but there 

 's no need in the tree for a specialized sensorium. 



The many-celled animals from the lowest to the highest, 

 •oear in their organization .some relation to locomotion. The 

 animal feeds on living creatures and these it must i)ursue if it 

 is to thrive. It is not the .sensitive nerve tij)s which are to 

 move; it is the whole creature. By the division of labor the 

 whole body of the comj^ound organism cannot be given over 

 to sensation. Hence the development of .'^en.^e organs dif- 

 ferent in character: one stimulated l)y waves of light, another 

 by waves of sound; one .sensitive to odor, another to taste; 

 still others to contact, temperature, nuiscular strain, and pain. 

 These sense organs nuist through their nerve fibers rc|>ort to 

 a sensorium which is distinct from each of them. And in 

 the process of specialization the sensorium itself is subdi- 



