An Introduction to a Biology 



misgiving as to the correctness of his interpretations 

 is that, however much he ought to have, he has 

 no misgivings about his observation, nor about 

 his descriptions of things, and we have seen that 

 he does not, as a rule, keep observation and inter- 

 pretation separate in his mind. So that observation 

 merges imperceptibly into interpretation. No line 

 is drawn to show where the one ends and the other 

 begins ; each becomes interpenetrated by the other^ 

 and we come to exist in the pleasant delusion that 

 interpretation is conducted in the same bright light 

 as that in which the work of observation is carried 

 on. A curious instance of this mutual interpene- 

 tration was afforded by the attitude of the Men- 

 delian and biometric schools to the Mendelian 

 phenomena of heredity, and the interpretation of 

 these phenomena. The Mendelian school were so 

 saturated with certainty as to the reality of the 

 Mendelian phenomena, by daily contact with them, 

 that their certainty spread across the border of 

 ascertained fact, well into the territory of hypo- 

 thesis. They could not understand how anyone who 

 was familiar with the facts could doubt the hypo- 

 thesis. The minds of the biometric school, on the 

 other hand, were so full of scepticism as to the 

 hypothesis that they looked with great suspicion 

 upon the facts. 



§4 



The interpretation of a phenomenon consists, in 

 current scientific phraseology, in discovering the 

 laws which govern that phenomenon. If it be the 

 case that the discovery of these laws is the goal of 



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