430 Prof. E. Hackel on the Calcispongige. 



6. The Calcispongue and Monism. 

 The most general results furnished bj the present monograph 

 of the Calcispongige are of a purely philosophical nature, and 

 may be summed up in the statement that the hiogeny of the 

 Calcispongice is a coherent proof of the truth of monism. In 

 mj 'General Morphology' I sought to demonstrate synthetically 

 that all the phenomena of the organic world of forms can be 

 explained and understood only by the monistic philosophy ; and 

 now this demonstration is furnished analytically by the mor- 

 phology of the Calcispongia3. The great contradictions of the 

 philosophical conceptions of the world, or between monism or 

 the mechanical and dualism or the teleological conception of 

 nature, which are rendered evident by every consistent reflec- 

 tion, may be tested in detail in the biology of the Calcispongise ; 

 and every examination turns out favom-able to the former and 

 disadvantageous to the latter. 



All the phenomena met with in the morphology of the Cal- 

 cispongise may be completely explained by the reciprocal 

 action of two physiological functions, inheritance and adapta- 

 tion ] and we need no other causes to comprehend their produc- 

 tion. All the causes which are found to be effective in the mor- 

 phology and physiology of the Calcispongi^ are unintelligent 

 mechanical causes [causm eficientes) ; and nowhere do we meet 

 with intelligent designedly active causes {causa; finales) . Every- 

 where we can detect the prevalence of unalterable natural laws, 

 nowhere the interposition of a preconceived plan of creation. 



It might appear that in the form-production of the Calci- 

 spongige every thing depended upon chance. But chance no 

 more exists in nature than design or freedom. All processes 

 are performed with absolute necessity, as the complex result 

 of the coincidence of numerous causes, each of which is of 

 purely mechanical nature, and itself again conditioned by more 

 distant causce efficientes. What we call chance is merely the 

 coincidence, unexpected by us, of circumstances each of which 

 is finally brought about with absolute necessity by a chain of 

 efficient causes. 



As all the phenomena presented to us by the biology of the 

 Calcispongise may be perfectly understood by the theory of 

 evolution, as a matter of course all assumption of a creation is 

 completely excluded in this department. But as the body of 

 the Calcispongige in the developmental stage of the Gastrula 

 already consists of the same two germ-lamellfe which compose 

 the body of man and of all the higher animals at an early 

 period of embryonic development, we must consistently assume 

 the same mechanical development for man also. This indica- 

 tion shows in the clearest manner the high importance of the 

 Calcispongige for the monistic philosophy. 



