24 ETHICAL ASPECTS OF EVOLUTION 



A still more general statement of the case is possible. 

 Irrespective of the special uses and drawbacks of each organ 

 regarded by itself, there is a general drawback which is 

 common to all. That is, that by the destruction, or even 

 by the imperfect functioning, of any one of them the activity 

 of the whole organism may be impaired or finally arrested. 

 Stated in its most general terms, forward evolution consists 

 in the multiplication of parts combined with an increased 

 solidarity between all of them. That this unity of purpose, 

 with division of labour, must greatly benefit the output of 

 work, in regard to both its quantity and its quality, is obvious ; 

 but it is not equally clear that it conduces to the stability 

 of the animal, or of the race. A very slight injury may 

 disable or kill a man, whereas a polypus will be none the 

 worse for being cut into many fragments. The more highly 

 specialized animal is far inferior to its lowly ancestors in 

 the power of repairing damaged parts, and of reproducing 

 them when lost, and every fresh specialization means a fresh 

 source of danger added to those which existed before. 

 Moreover, the more highly developed an organ is, the greater, 

 as a rule, are both its value and its liability to derangement. 

 It is only necessary to instance the eye and the brain of man. 



When, therefore, we appeal to facts, we do not find that 

 it is the most highly developed types that have subsisted 

 longest in the general struggle with the environment. It 

 is known that on continents mammals appear and disappear 

 at a quicker rate than other and lower animals. 1 The 

 protozoa have survived innumerable species of their more 

 highly organized descendants, and are likely to survive many 

 more. Of all the species which occupied the highest places 

 immediately before the advent of man, scarcely one has 

 endured to our day. In the special case of a conflict between 

 different species, instances where the lower type triumphs 

 over the higher are numerous. The degenerate dodder 

 kills the most highly developed plants, wheat is destroyed 

 by blight and rust, civilized empires have been overthrown by 

 hordes of savages. The list is endless. In his own struggle 

 1 Origin of Species, xii. 469, 4th edition. 



