Chapter XII 

 POINTER READINGS 



Familiar Conceptions and Scientific Symbols. We have 

 said in the Introduction that the raw material of the 

 scientific world is not borrowed from the familiar world. 

 It is only recently that the physicist has deliberately cut 

 himself adrift from familiar conceptions. He did not 

 set out to discover a new world but to tinker with the 

 old. Like everyone else he started with the idea that 

 things are more or less what they seem, and that our 

 vivid impression of our environment may be taken as 

 a basis to work from. Gradually it has been found that 

 some of its most obvious features must be rejected. We 

 learn that instead of standing on a firm immovable earth 

 proudly rearing our heads towards the vault of heaven, 

 we are hanging by our feet from a globe careering 

 through space at a great many miles a second. But this 

 new knowledge can still be grasped by a rearrangement 

 of familiar conceptions. I can picture to myself quite 

 vividly the state of affairs just described; if there is any 

 strain, it is on my credulity, not on my powers of con- 

 ception. Other advances of knowledge can be accommo- 

 dated by that very useful aid to comprehension — "like 

 this only more so". For example, if you think of some- 

 thing like a speck of dust only more so you have the 

 atom as it was conceived up to a fairly recent date. 



In addition to the familiar entities the physicist had 

 to reckon with mysterious agencies such as gravitation 

 or electric force; but this did not disturb his general 

 outlook. We cannot say what electricity is "like"j but 



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