DEMONSTRATION, AND NECESSARY TRUTHS. 319 



efforts of genius and patience, have, when once 

 established, appeared so self-evident that, but for 

 historical evidence, it would have been impossible to 

 conceive that they had not been recognised from the 

 first by all persons in a sound state of their faculties. 

 " We now despise those who, in the Copernican 

 controversy, could not conceive the apparent motion 

 of the sun on the heliocentric hypothesis ; or those 

 who, in opposition to Galileo, thought that a uniform 

 force might be that which generated a velocity pro- 

 portional to the space ; or those who held there was 

 something absurd in Newton's doctrine of the different 

 refrangibility of differently coloured rays ; or those 

 who imagined that when elements combine, their 

 sensible qualities must be manifest in the compound ; 

 or those who were reluctant to give up the distinction 

 of vegetables into herbs, shrubs, and trees. We 

 cannot help thinking that men must have been 

 singularly dull of comprehension to find a difficulty 

 in admitting what is to us so plain and simple. We 

 have a latent persuasion that we in their place should 

 have been wiser and more clearsighted ; that we 

 should have taken the right side, and given our 

 assent at once to the truth. Yet in reality such a 

 persuasion is a mere delusion. The persons who, in 

 such instances as the above, were on the losing side, 

 were very far in most cases from being persons more 

 prejudiced, or stupid, or narrow-minded, than the 

 greater part of mankind now are ; and the cause for 

 which they fought was far from being a manifestly 

 bad one, till it had been so decided by the result of 

 the war . . So complete has been the victory of 

 truth in most of these instances, that at present we 

 can hardly imagine the struggle to have been neces- 

 sary. The very essence of these triumphs is, that they 



