Art and Science 



Those who accept evolution insist on un- 

 broken physical continuity between the earliest 

 known life and ourselves, so that we both are 

 and are not personally identical with the uni- 

 cellular organism from which we have de- 

 scended in the course of many millions of 

 years, exactly in the same way as an octogen- 

 arian both is and is not personally identical 

 with the microscopic impregnate ovum from 

 which he grew up. Everything both is and 

 is not. There is no such thing as strict 

 identity between any two things in any two 

 consecutive seconds. In strictness they are 

 identical and yet not identical, so that in 

 strictness they violate a fundamental rule of 

 strictness namely, that a thing shall never 

 be itself and not itself at one and the same 

 time ; we must choose between logic and 

 dealing in a practical spirit with time and 

 space ; it is not surprising, therefore, that 

 logic, in spite of the show of respect outwardly 

 paid to her, is told to stand aside when people 

 come to practice. In practice identity is 

 generally held to exist where continuity is 



only broken slowly and piecemeal, neverthe- 



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