i9o6.] LOGICAL AND BIOLOGICAL. 73 



nine cows and five apples, wonders whether the result is horses or 

 cows or apples. If he were to attribute the virtue of his arithmetic 

 to a substance of numeration and to wonder whether it resides in * 

 cows or apples, he would be still more like those who speculate about 

 the location of the substance of inheritance, and think they have put 

 their finger on it when they have called it idioplasm. 



If you choose to declare that my contention, that inheritance is 

 not a fact, is a metaphysical subtilty, I cannot help it. Call me a 

 metaphysician if you will. But may it not be the speculative biol- 

 ogist who hunts in germ cells and in their chromatin for the physical 

 basis of the crudity of his ideas who is the true metaphysician, and 

 not I, who plead for nothing but the correction of our scientific con- 

 cepts and their reduction to exactness by comparison with nature ? 



Science is making marvellous revelations of the order that per- 

 vades the apparent disorder of nature, showing us, by the method of 

 analysis and comprehension, the most wonderful and admirable evi- 

 dence of regularity in the course of events that had seemed to be 

 chaotic, but this statistical method deals with averages while the 

 natural world is concrete. No living being is a statistical average, 

 and it is the peculiar task of biological science to recall our attention 

 to the diversity of the statistical data, thus making equally marvel- 

 lous and equally instructive revelations of the inexhaustible variety 

 and boundless wealth of nature, for science deals with progress and 

 discovery, not with finality, and the test of truth is nature and not 

 logic. 



Statistical science shows that there is, on the average, about one 

 chance in some thousands that the average human being will com- 

 mit murder or suicide within the year, but my friend is not a two 

 hundred thousandth of a murderer, and I prize him because there is 

 no one like him. 



The biometricia.n tells us of a standard or norm, from which 

 living beings recede by variation, and to which they approximate 

 by heredity, but the normal or average living being does not exist 

 in nature. The student of statistical science talks glibly of the 

 normal man as if he were a public character, the familiar acquaint- 

 ance of men of intellect, and a well known face to even the com- 

 mon herd. The biologist declares that he knows no such person ; 



