Nervous System 



393 



tions, undoing all the gains achieved by 

 laboriovis factual analysis. If it were more 

 generally realized that the svibject matter 

 of biology is really more nearly cognate to 

 that of engineering than that of plain 

 physics — that in biology we not only have 

 to establish and reconfirm the validity of 

 general laws and principles, bvit also have 

 to clarify the complex mechanisms of their 

 operation — then the demand for sweeping 

 generalizations would rapidly subside. The 

 deeper we have penetrated into the analysis 

 of neurogenesis, the more component proc- 

 esses we have been able to identify and 

 single out for methodical analysis. From 

 this analysis, and only after it, have we 

 gained certainty that the component proc- 

 esses are really of many diverse kinds — that 

 the complexity which we encounter is not 

 due to our dearth of knowledge or lack of 

 comprehension but is inherent in our subject, 

 much as it is in a machine. Simplicity, and 

 not complexity, is the illusion. 



But faced with this reality, the task of dis- 

 entangling the complexity and reducing it 

 to an irreducible minimum of elementary 

 events and their interactions becomes all the 

 more challenging. The picture that emerges 

 is a most intricate web of interrelations, each 

 thread definable and either known or ame- 

 nable to further experimental or conceptual 

 resolution. It seems fitting, therefore, to 

 conclude our discussion with a pictorial 

 representation of this web, constructed ac- 

 cording to the analytical results detailed in 

 the text (Fig. 144). The single- and double- 

 headed arrows express causal relations and 

 interrelations, respectively. Most of these 

 can be found documented in our discussion. 

 This diagram, however crude and incomplete, 

 is still the most pertinent summary of neuro- 

 genesis that there could be; as such it gives 

 a fair portrayal in miniature of the develop- 

 mental process in general. 



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