4 DEGEXERATIOX : I 



one great branch of science, as there is in biology, so 

 very marked a disproportion between the facilities for 

 demonstrating facts and the general interest attaching 

 to the theories connected with those facts. We may 

 be thankful that at the present day we are not likely, 

 in the domain of biology, to make the mistake (which 

 has been made under other circumstances) of substitut- 

 ing the mere inspection and cataloguing of natural 

 objects for that more truly scientific attitude which 

 consists in assigning the facts which come under our 

 observation to their causes, or, in other words, to their 

 places in the order of nature. Though we may rightly 

 object to the attempt which is sometimes made to 

 decry the modern teachings of biology as not being 

 " exact science," yet we may boldly admit the truth 

 of the assertion that we biologists are largely occupied 

 with speculations, hypotheses, and other products of 

 the imagination. All true science deals with specula- 

 tion and hypothesis, and acknowledges as its most 

 valued servant — its indispensable ally and helpmeet 

 — that which our German friends^ call " Phantasie " 

 and we " the Imagination." Our science, biology, 

 is not less exact — our conclusions are no less accurate 

 because they are only 2^'i'ohahly true. They are " prob- 

 ably true" with a degree of probability of which 

 we are fully aware, and which is only somewhat less 

 than the probability attaching to the conclusions 

 of other sciences which are commonly held to be 

 " exact." 



These remarks are addressed to an Association for 



1 See Note A. 



