philosophies, that there is no such thing as absolute truth, 

 but that as our knowledge increases, the concepts which 

 we regard as being true will require modification. It is 

 only possible, at any one time, for us to say that our present 

 concepts are more true than those of the past; that is, we 

 can accept the relativity of truth only. We can never claim 

 to have reached finality in anything. 



For all people who are looking for a better way of 

 life on Earth, which means in fact a large part of the 

 world's population, the well-established capability of sci- 

 ence to provide satisfactory solutions to problems of 

 many different kinds is a very strong point in its favor. No 

 other existing human way of thought-with-action has been 

 able to even suggest ways in which the enormous prob- 

 lems of Mankind — population growth, nutrition, disease, 

 industrial economics, migration to undeveloped lands, 

 and war — could be solved. But science has given us 

 successes in so many fields that it would take a long time 

 to mention them all, and in some fields great successes 

 beyond the fondest hopes of the ancients. Such are: an 

 understanding of the nature of the Universe; knowledge 

 of the source of the Sun's energy, and the release of 

 nuclear energy for ourselves; knowledge of the interior 

 structure of the Earth, of the formation of its surface 

 features, and of its age; an accurate conception of the 

 evolution of life on Earth from primitive forms, including 

 the actual ages of many of the ancestors of modem species; 

 considerable knowledge regarding the working of the 

 human body; precise knowledge of the causes of many 

 diseases, and of means for curing them; the ability to travel 

 by land, sea and air at high speeds; the ability to com- 

 municate over great distances at the speed of radio waves; 

 a remarkable understanding of the structure of matter; 



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