THE ART OF SCIENTIFIC INVESTIGATION 



at birth many discoveries. Obscurantism and authoritarianism 

 are not yet dead. 



Included among the many possible sources of fallacy are 

 post hoc, ergo propter hoc, comparing groups separated by time, 

 assuming that when two factors are correlated the relationship 

 is necessarily one of cause and effect, and generalising from 

 observations on samples that are not representative. 



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