362 Professor Huxley [April 9, 



stalwart personage, upon whom mere goody scoldings and threatenings 

 with the birch-rod were quite thrown away. 



In fact, those who have watched the progress of science within 

 the last ten years will bear me out to the full when I assert that 

 there is no field of biological inquiry in which the influence of the 

 ' Origin of Species ' is not traceable ; the foremost men of science in 

 every country are either avowed champions of its leading doctrines, 

 or at any rate abstain from opposing them; a host of young and 

 ardent investigators seek for and find inspiration and guidance in 

 Mr. Darwin's great work ; and the general doctrine of Evolution, to 

 one side of which it gives expression, finds in the phenomena of 

 biology a firm base of operations whence it may conduct its conquest 

 of the whole realm of nature. 



History warns us, however, that it is the customary fate of new 

 truths to begin as heresies and to end as superstitions ; and, as 

 matters now stand, it is hardly rash to anticipate that, in another 

 twenty years, the new generation, educated under the influences of 

 the present day, will be in danger of accepting the main doctrines 

 of the ' Origin of Species ' with as little reflection, and it may be with 

 as little justification, as so many of our contemporaries, twenty years 

 ago, rejected them. 



Against any such a consummation let us all devoutly pray ; for 

 the scientific spirit is of more value than its products, and irration- 

 ally-held truths may be more harmful than reasoned errors. Now 

 the essence of the scientific spirit is criticism. It tells us that to 

 whatever doctrine claims our assent we should reply, Take it if 

 you can compel it. The struggle for existence holds as much in the 

 intellectual as in the physical world. A theory is a species of think- 

 ing, and its right to exist is coextensive with its power of resisting 

 extinction by its rivals. 



From this point of view it appears to me that it would be but a 

 poor way of celebrating the Coming of Age of the ' Origin of Species ' 

 were I merely to dwell upon the facts, undoubted and remarkable as 

 they are, of its far-reaching influence and of the great following of 

 ardent disciples who are occupied in spreading and developing its 

 doctrines. Mere insanities and inanities have before now swollen to 

 portentous size in the course of twenty years. Let us rather ask 

 this prodigious change in opinion to justify itself; let us inquire 

 whether anything has happened since 1859 which will explain, on 

 rational grounds, why so many are worshipping that which they 

 burned, and burning that which they worshipped. It is only in this 

 way that we shall acquire the means of judging whether the move- 

 ment we have witnessed is a mere eddy of fashion, or truly one with 

 the irreversible current of intellectual progress, and, like it, safe from 

 retrogressive reaction. 



Every belief is the product of two factors : the first is the state 

 of the mind to which the evidence in favour of that belief is 

 presented ; and the second is the logical cogency of the evidence 



