18 SCIENTIST 



followed by the child who comes to the conclusion that 

 all objects fall to the ground when they are pushed off 

 tables. Good scientific generalizations are more general 

 than this; that is, they say something about how the object 

 will move if we throw it as well as if we merely drop it. 

 They also describe the result in more precise quantitative 

 terms — how long it will take to reach the ground, for 

 example. 



It should be said as soon as possible that scientific gen- 

 eralizations are no more true in any absolute sense than 

 the conclusions reached by the child. To explain what we 

 mean by this, we can notice that sooner or later most 

 children will encounter an instance in which an object 

 released from the hand will go up instead of down. He 

 will then have to modify his statement about all objects 

 and make room for very light round objects called bal- 

 loons. In exactly the same way, the scientific world after 

 250 years of complete confidence in Newton's "laws" found 

 that they did not account for certain events involving very 

 small particles and very high speeds. It was Einstein, of 

 course, who provided the equations to deal with such 

 instances. 



The spectacular progress of science between the six- 

 teenth and nineteenth centuries had tended to make men 

 feel that at last a method had been found which could 

 bring us to an understanding of ultimate truth. The Ein- 

 steinian revolution was a great shock and caused a number 

 of scientists and philosophers to reexamine the logical 

 foundations of science. The discussion is a difficult one 

 to follow and we wiU mention only the conclusion and a 

 few of the high points here. The conclusion essentially 

 is that science has no way of being absolutely sure that 

 what it says is "true." About the best that can be said 

 is that we believe scientific statements because they work 



