PROBLEM OF ORIGIN OF SPECIES 45 



presuppositions. According to this doctrine, species-forming varia- 

 bility goes on without regard to the qualification of the new species 

 for maintaining themselves in life. It simply supplies the struggle 

 for existence with the material for natural selection. Whether this 

 selection takes place between individuals, as Darwin and Wallace 

 supposed, or decides between whole species, as the mutation-theory 

 demands, ultimately it is, in either case, simply the ability for exist- 

 ence under given external conditions that decides upon the perman- 

 ence of the new form " (p. 180). 



I take exception here only to the implication that a definite 

 variation-tendency must be considered to be teleological because it 

 is not "orderless." I venture to assert that variation is sometimes 

 orderly, and at other times rather disorderly, and that the one is 

 just as free from teleology as the other. In our aversion to the old 

 teleology, so effectually banished from science by Darwin, we should 

 not forget that the world is full of order, the organic no less than the 

 inorganic. Indeed, what is the whole development of an organism 

 if not strictly and marvelously orderly? Is not every stage, from 

 the primordial germ onward, and the whole sequence of stages, rigidly 

 orthogenetic? If variations are deviations in the directions of the 

 developmental processes, what wonder is there if in some directions 

 there is less resistance to variation than in others? What wonder if 

 the organism is so balanced as to permit of both unifarious and 

 multifarious variations? If a developmental process may run on 

 throughout life (e. g., the lifelong multiplication of the surface-pores 

 of the lateral-line system in Amia), what wonder if we find a whole 

 species gravitating slowly in one or a few directions? And if we find 

 large groups of species all affected by a like variation, moving in the 

 same general direction, are we compelled to regard such "a definite 

 variation-tendency" as teleological, and hence out of the pale of 

 science? If a designer sets limits to variation in order to reach a 

 definite end, the direction of events is teleological; but if organization 

 and the laws of development exclude some lines of variation and 

 favor others, there is certainly nothing supernatural in this, and 

 nothing which is incompatible with natural selection. Natural selec- 

 tion may enter at any stage of orthogenetic variation, preserve and 

 modify in various directions the results over which it may have had 

 no previous control. 



It has always appeared to be one of the greatest difficulties for 

 natural selection to account for the incipient stages of useful organs. 

 Orthogenesis, as I hope to make clear, removes this difficulty from a 

 large portion of the field. 



It should be noted in this connection that the difficulty of incipient 

 stages is not what it is so generally presumed to be. The advocates 

 of natural selection habitually assume that the evolution of an organ 



