Chap. V. RACE DIFFERENCES
Ginsberg1 has defined a race as “ a group of people who, within given limits of variation, possess in common a combina tion of hereditary traits sufficient to mark them off from other groups.’5 The criteria for race, according to this definition, and indeed according to most definitions, are therefore physical (whereas the criteria for distinguishing between nations are largely psychological). But difficulties in classification at once arise in determining what “ limits o f variation” we shall allow ourselves. Whether or not a particular group of people may be referred to as belonging to a particular race will largely turn on the degree of variation of these hereditary traits which we allow ourselves to employ.