PHILOSOPHICAL ASPECTS OF EVOLUTION 



and certainly not the main one why scientists advocated 

 abiogenesis. They had a very sound philosophical reason 

 which in itself had nothing to do with materialism, except 

 that in the past so-called materialists did understand this 

 reason better than other philosophers. 



In order to see this reason, we have to dwell a moment 

 upon a problem that dominates the history of biology and 

 that if. known as the antithesis between mechanicism (or 

 materialism) and vitalism. A short analysis of this antithesis 

 will teach us some important things about the nature of science 

 and about the distinction between science and philosophy. It 

 will also clarify much of the background of the dispute around 

 evolution. 



2. Mechanicism and Vitalism 



The main point of the conflict between mechanicism and 

 vitalism can be formulated in the question whether or not all 

 phenomena of life can be explained by purely physical and 

 chemical factors. Mechanicists answer the question in the 

 affirmative, vitalists in the negative. The latter think it 

 necessary to assume that in any living being there is present 

 a special factor, a vital force or entelechy. The still current 

 term organic chemistry originated from that opinion. Organic 

 compounds were believed to be formed exclusively in living 

 bodies under the influence of the vital force. It would, there- 

 fore, be impossible to synthesize them in a test tube. Scientists, 

 however, do not like the word impossible, especially when it 

 is only the reflection of the empirical status quo. They always 

 try to do the impossible. 



In 1828 Wohler succeeded in synthesizing urea, and from 

 that time on so many organic compounds were produced, that 

 there was no longer any doubt concerning the possibility of 

 synthesizing all organic compounds in the test tube. 



However, that did not discourage vitalism. It could point at 

 enough other aspects of living organisms to endorse its fun- 

 damental thesis that not all phenomena of life could be 

 explained by chemistry. Famous are, for example, the startling 

 phenomena of regulation and regeneration, studied by Hans 

 Driesch. After a great number of skillful experiments, he 

 pointed out that the development of a young embryo did not 



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