36 INTRODUCTION TO SCIENCE 



scientific mood becomes aware of certain facts 

 that interest him; he proceeds to become more 

 intimately aware of them; to make his sensory 

 experience of them as full as possible. Careful 

 and critical observation is the first step. 



This work of Science, which we may call get- 

 ting at the facts, is much more difficult of attain- 

 ment than those who have not tried imagine. One 

 reason for this is very familiar, that things are 

 not always what they seem to be. And though 

 Science does not raise the characteristic meta- 

 physical question as to w T hat is meant by being 

 real, it has in its own way to distinguish seeming 

 from reality. The sun does not rise and set, the 

 stable Earth is a whirling sphere, the inert body 

 may be a vortex of rapidly moving corpuscles, 

 and so on. If Science is to be consistent it has to 

 set itself to the task of distinguishing realities 

 from appearances. 



Having got his facts, the scientific investigator 

 proceeds to arrange them, to find their common 

 denominator, to discover the conditions of their 

 occurrence, and to describe them as completely 

 and as simply as possible, and finally to sum 

 them up in a general formula, often called "a 

 law of nature." 



Aristotle defined this aim when he said: "Art 

 [or, as we should say, Science] begins when, from 

 a great number of experiences, one general con- 



