212 ETHICAL ASPECTS OF EVOLUTION 



few who will not admit that the belief that corrupt perjury 

 ought to be condemned is at least as certain as any article 

 of knowledge ; or would give it up in favour of a scientific 

 demonstration, were one possible, that the guilty person is 

 no more a just object of blame than the wind or the clouds. 



The effects of training and imitation are most strikingly 

 and unmistakably shown in the great waves of thought 

 which pass over human societies. If one age is essentially 

 scientific and another essentially religious, it is not because 

 the individual minds are differently constituted, but because 

 men have been accustomed, either by purposive training, 

 or by observation of their fellows, in the first to attach the 

 higher value to knowledge, and in the second to beliefs. 



The practical or teleological distinction which divides 

 articles of knowledge from articles of belief is that the former 

 enable us, within their own sphere, that is, within the limits 

 of the external world, to predict the future ; whereas the 

 others do not. Should it be objected to this assertion that 

 it is too sweeping, and that we actually do predict events in 

 the subjective world, such as the intentions and actions 

 of ourselves or of our friends, it is at any rate safe to say 

 that, while objective predictions are of the highest degree 

 of certainty, and hold good for a remote future, the others 

 are never more than probable, and not even that beyond 

 very short periods of time. The reason is that in objective 

 problems, where science is sufficiently advanced, we can 

 always give an exact account of, at any rate, a considerable 

 number of factors, and often of as many as we require for 

 the purposes of prediction ; whereas in subjective problems 

 we can never give an exact account of any single factor ; 

 we have nothing but personal estimates. * Those precise 

 definitions which ensure to every word the same exact signi 

 fication in the mind of every one who hears it pronounced l 

 are wholly wanting, and without them we can formulate 

 no law which has objective validity. 



For our present purpose events may be arranged in the 

 following classes. In the first are those in which our pre- 

 1 T. Brown, Philosophy of the Mind, i. 93. 



