40 MAN THE ANIMAL 



individual human beings. It is one of the most obvious truisms 

 of biology that no two living individuals are exactly alike in 

 any respect, whether of form, or function, or chemical constitu- 

 tion. We know a great deal about these differences between 

 individual men. An enormous amount of effort in the aggregate 

 has gone into the measuring of them. The whole science of 

 physical anthropology is made up of such efforts and their 

 results. A great part of present-day psychology is turned in the 

 same direction. What broad generalizations have resulted from 

 these efforts? 



There are three such generalizations that it seems important to 

 discuss. The first is that many more men differ from each other 

 by small amounts in respect of any characteristic whatsoever 

 than differ by large amounts. This is a universal law of variation 

 in the organic world and an expression of its inherent stability. 

 The distribution of individual differences tends to cluster about 

 a center of variation, which is regarded as the typical condition 

 or norm for that character. Average, run-of-mine individuals 

 are much more frequent than outsize freaks in whatever respect 

 they may be observed. This first generalization about individual 

 variation is really no more than a simple description of how 

 the world of living things is organized. It has inherently no 

 occult meaning, and in fact baffles any inquiry as to why it 

 happens to be so, quite as completely as does the fact that bodies 

 attract each other in proportion to their respective masses. It 

 also illustrates the fact that such concepts about natural phe- 

 nomena as "normal," "typical" or "truth" itself are merely the 

 expressions of majority opinions so widely concurrent and 

 congruous as to be practically universal. To illustrate: in a 

 world so organized that the differences between men in stature 

 were so distributed as to yield a U-shaped curve instead of in 

 a cocked-hat curve, as they are in fact, "norrnal" or "typical" 

 men would be either very short men or very tall men. In such 

 a world the freak would be the man of average height. The only 

 reason why in our world men of about average height are "typi- 

 cal" and "normal" is that there are so many more of them that 



