THE DOGMA OF EVOLUTION 



rate realms and investigates their relations. As the 

 fourth and last mode of thought, we can instance a 

 dualism of the physical scientist. The two realms are 

 here recognized as existent but the phenomena of life 

 are excluded as not subject to scientific investigation. 

 Newton and Lord Kelvin are eminent types. They 

 maintained an attitude of piety and accepted the in- 

 spiration of the Bible as entirely consistent with a 

 belief in a rigorous natural law in the physical world. 



There is wide difference of opinion as to the value 

 of the achievements of the Greeks in science. Their 

 successes and failures can be distinguished best by 

 keeping clearly in mind the two aspects of science. 

 Before we can derive particular laws or generaliza- 

 tions from our data of observation, we must agree 

 on certain fundamental ideas, or postulates, which 

 are to be kept as few in number as possible. These 

 postulates are deductive, or even intuitional; that is, 

 they are not founded on experience, but they are 

 true because the consensus of opinion accepts them 

 and believes them to be necessary if we are to find 

 any law and order in the world. A famous instance of 

 such deduction is the postulate of geometry that the 

 straight line is the shortest distance between two 

 points, evidently a truth not based on experience. 



There are certainly four of these deductive postu- 

 lates in science which have a direct bearing on evolu- 

 tion. We must accept the conservation of matter. 



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