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 
atself, 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. 
Il. 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 
