IV 



Aggregations of Higher Animals 



A GREAT deal of skepticism is necessary in science, 

 if progress is to be even relatively steady and sound. 

 Not only must the scientist be skeptical of advance 

 reports of new results until he has seen the support- 

 ing evidence, no matter how stimulating the thesis 

 and how well it would explain material already 

 gathered; but in fields which lie near his own re- 

 searches it is necessary if possible to bring the prob- 

 lem into his own laboratory and there examine the 

 validity of the evidence itself. This repeating of ex- 

 periments in order to check the first observer is some- 

 times also a testing of scientific courtesy, but every 

 real scientist must be prepared to submit to it with 

 the best grace possible. 



It is demanded also that from time to time one 

 should be skeptical of views long held, and of the 

 evidence on which they were built up, particularly 

 of the inclusiveness of the conclusions that have been 

 drawn. Without my own fair share of this skepticism 

 I should never have been drawn into what I knew 



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