i IMPERFECTION OF OUR KNOWLEDGE 27 



composition of our own bodies. How, then, can we expect 

 to answer such questions when they relate to animals known 

 to us only by dead specimens, or by the most transient 

 glimpses of the living in a state of nature, or when kept 

 under the most unnatural conditions in confinement ? And 

 yet this is actually the state of our knowledge of the vast 

 majority of the myriads of living beings which inhabit the 

 earth. How can we, with our limited powers of observation 

 and limited capacity of imagination, venture to pronounce 

 an opinion as to the fitness or unfitness for its complex 

 surroundings of some peculiar modification of structure found 

 in some strange animal dredged up from the abysses of the 

 ocean, or which passes its life in the dim seclusion of some 

 tropical forest, and into the essential conditions of whose 

 existence we have at present no possible means of putting 

 ourselves in any sort of relation ? 



How true it is that, as Sir John Lubbock says, " we find 

 in animals complex organs of sense richly supplied with 

 nerves, but the functions of which we are as yet powerless 

 to explain. There may be fifty other senses as different from 

 ours as sound is from sight ; and even within the boundaries 

 of our own senses there may be endless sounds which we cannot 

 hear, and colours as different as red from green of which we 

 have no conception. These and a thousand other questions 

 remain for solution. The familiar world which surrounds us 

 may be a totally different place to other animals. To them 

 it may be full of music which we cannot hear, of colour which 

 we cannot see, of sensations which we cannot conceive." 



The fact is that nearly all attempts to assign purposes to 

 the varied structures of animals are the merest guesses and 

 assumptions. The writers on natural history of the early part 

 of the present century, who " for every why must have a 

 wherefore," abound in these guesses, which wider knowledge 

 shows to be untenable. Many of the arguments for or against 

 natural selection, based upon the assumed utility or equally 

 assumed uselessness of animal and vegetable structures, have 

 nothing more to recommend them. In fact, to say that any 

 part of the organisation of an animal or plant, or any habit or 

 instinct with which it is endowed, is useless, or even injurious, 



