320 FALLACIES. 



not merely conceivable, but even explainable, it could not exist 

 in nature. All natural phenomena, according to him, must be 

 susceptible of being accounted for a priori. The only facts of 

 which no explanation could be given but the will of God, were 

 miracles properly so called. " Je reconnais," says he,* " qu'il 

 n'est pas permis de nier ce qu'on n'entend pas; mais j'ajoute 

 qu'on a droit de nier (au moins dans 1'ordre naturel) ce qui 

 absolument n'est point intelligible ni explicable. Je soutiens 

 aussi .... qu'enfin la conception des creatures n'est pas 

 la mesure du pouvoir de Dieu, mais que leur conceptivite, ou 

 force de concevoir, est la mesure du pouvoir de la nature, tout 

 ce qui est conforme a 1'ordre naturel pouvant etre con9u ou 

 entendu par quelque creature." 



Not content with assuming that nothing can be true which 

 we are unable to conceive, scientific inquirers have frequently 

 given a still further extension to the doctrine, and held that, 

 even of things not altogether inconceivable, that which we can 

 conceive with the greatest ease is likeliest to be true. It was 

 long an admitted axiom, and is not yet entirety discredited, 

 that " nature always acts by the simplest means," i.e. by those 

 which are most easily conceivable.f A large proportion of all 

 the errors ever committed in the investigation of the laws of 

 nature, have arisen from the assumption that the most familiar 

 explanation or hypothesis must be the truest. One of the 

 most instructive facts in scientific history is the pertinacity 

 with which the human mind clung to the belief that the 

 heavenly bodies must move in circles, or be carried round by 

 the revolution of spheres ; merely because those were in them- 

 selves the simplest suppositions : though, to make them accord 

 with the facts which were ever contradicting them more and 

 more, it became necessary to add sphere to sphere and circle to 

 circle, until the original simplicity was converted into almost 

 inextricable complication. 



* Nouveaux JEssais sur VEntendement Humain Avant-propos. (CEuvres, 

 Paris ed. 1842, vol. i. p. 19.) 



f This doctrine also was accepted as true, and conclusions were grounded 

 on it, by Sir William Hamilton. See Examination, chap. xxiv. 



