282 THE FOUR INSEPARABLE FACTORS OF EVOLUTION, 

 ment, although there may be a dysteleology of side currents, of lagging characters 



as 



in which the blastos does not, so to speak, keep pace with the soma, as well 

 of neutral characters which do not appear to be adaptive. This mutability, or 

 evolution movement, or whatever it is that is in progress in the blastos is the 

 chief and most difficult matter either to explain or to form any conception of. 



Emphasis may be laid on the words adaptive need or necessity because there 

 is distinct evidence in palaeontology that the blastos is not evolving alone through 

 its internal forces independently of the external forces of ontogeny and of en- 

 vironment, but that there is some harmony or form of interaction, the nature of 

 which we do not understand. 



The appearances which the palaeontologist observes in the origins of character 

 and the transformations of character are simply modes of evolution. It is, how- 

 ever, from the analysis of these modes of evolution as well as by experiment that 

 we must ultimately discover the causes or factors, if, indeed, they are discoverable. 

 These modes of evolution present themselves under such widely different aspects 

 to different classes of observers that we are reminded of the fable of the ele- 

 phant and the nine blind men, who formed nine entirely different opinions as 

 to the nature of the animal through judging wholly by the respective parts with 

 which the hands of each happened to come in contact. The stout opinions of 

 these nine blind men have their more or less clear counterparts in modern bio- 

 logical investigators, who are in reality studying different aspects merely of the 

 same great phenomena. There is first the standpoint of the natural philosopher 

 of the Herbert Spencer type ; then that of the systematic zoologist and field natur- 

 alist or botanist ; of the breeder, horticulturalist, and fancier, typified by Mendel, 

 De Vries, and Bateson, working in an entirely different field of facts; of the 

 anthropologists and anatomists who deal again with a distinct class of phenom- 

 ena; akin to this is the work of the student of animal mechanics. Then there 

 are the observers of geographical distribution and segregation, such as Gulick 

 and Ortman. In the opposite extreme the observers of cell structure, such as 

 Nageli, Boveri, and Wilson are in a circumscribed field of their own. The 

 experimentalist is on the borderland between the field naturalist, the student of 

 cell structure, and the student of animal mechanics. The biological statistician 

 has his own field of observation. The palaeontologists have divided into two 

 groups, those who have directly observed the origin and transformation of 

 character, like Waagen and Hyatt, and those who have entered into mechanical 

 explanations, like Cope. The subjective and objective elements in observation 

 and induction may be expressed thus: 



DiffcrGiiCBS in thp l 

 knowledge, person- Differences in the I Differences »* the I ^-^ inductions 



of the observer I I of these ob J ecta 



It is a familiar psychic process that predisposition for a certain theory causes 

 corresponding aberration of vision; facts which agree with one's theory are seen 



