28 INDIVIDUALITY IN ORGANISMS 



Various biological theories have concerned them- 

 selves primarily with that particular aspect of unity and 

 order which appears in the geometrical relations of parts. 

 These are commonly known as theories of polarity and 

 symmetry, but since polarity and symmetry are funda- 

 mental features of organic individuality, these theories 

 must be regarded as theories of the organic individual. 

 It is unnecessary to discuss these theories particularly, 

 for they fall into the same groups as those already con- 

 sidered, and are open to the same objections. They 

 either assume the existence of some kind of structural 

 order or '^ organization," physical or chemical, or some 

 sort of pre-existent plan or pre-established harmony, 

 or they ignore or fail to recognize the real problem and 

 postulate migrations or distributions of formative sub- 

 stances, differences in tension, permeability, or other 

 properties, as if such factors could behave in an orderly 

 and constant way without a constant underlying order 

 of some sort. 



Some few biologists have attempted to deny the 

 existence of individuality in the sense of a definite 

 determining and controlling unity and order. The 

 basis of such denials is usually the fact that organisms 

 behave differently under different external conditions, 

 while the more important fact that a definite unity and 

 order exists in these different reactions is completely 

 overlooked. 



This brief consideration of the various lines of 

 biological thought concerned with the problem of the 

 individual is sufficient to show that the problem is by no 

 means solved. The remainder of the present book is an 

 attempt to make some progress toward a solution of the 



