The Lamarckian Principle 21 



individual or " fluctuating " variations, a part may be added here or 

 dropped out there, and thus something new is produced. 



The principle of selection solved the riddle as to how what was 

 purposive could conceivably be brought about without the inter- 

 vention of a directing power, the riddle which animate nature 

 presents to our intelligence at every turn, and in face of which the 

 mind of a Kant could find no way out, for he regarded a solution 

 of it as not to be hoped for. For, even if we were to assume an 

 evolutionary force that is continually transforming the most primitive 

 and the simplest forms of life into ever higher forms, and the homo- 

 geneity of primitive times into the infinite variety of the present, 

 we should still be unable to infer from this alone how each of the 

 numberless forms adapted to particular conditions of life should have 

 appeared precisely at the right moment in the history of the earth to 

 which their adaptations were appropriate, and precisely at the proper 

 place in which all the conditions of life to which they were adapted 

 occurred : the humming-birds at the same time as the flowers ; the 

 trichina at the same time as the pig ; the bark-coloured moth at the 

 same time as the oak, and the wasp-like moth at the same time as the 

 wasp which protects it. Without processes of selection we should 

 be obliged to assume a "pre-established harmony" after the famous 

 Leibnitzian model, by means of which the clock of the evolution of 

 organisms is so regulated as to strike in exact synchronism with that 

 of the history of the earth ! All forms of life are strictly adapted 

 to the conditions of their life, and can persist under these conditions 

 alone. 



There must therefore be an intrinsic connection between the 

 conditions and the structural adaptations of the organism, and, 

 since the conditions of life cannot be determined by the animal 

 itself the adaptations must be called forth by the conditions. 



The selection theory teaches us how this is conceivable, since it 

 enables us to understand that there is a continual production of what 

 is non-purposive as well as of what is purposive, but the purposive 

 alone survives, while the non-purposive perishes in the very act of 

 arising. This is the old wisdom taught long ago by Empedocles. 



II. The Lamarckian Principle. 



Lamarck, as is well known, formulated a definite theory of evolu- 

 tion at the beginning of the nineteenth century, exactly fifty years 

 before the Darwin-Wallace principle of selection was given to the 

 world. This brilliant investigator also endeavoured to support his 

 theory by demonstrating forces which might have brought about the 

 transformations of the organic world in the course of the ages. In 



