endeavor to be rational, to forego at least some of our 
     emotional social needs, to look after ourselves, and to 
     accept responsibilities. We must, I believe, bear this strain 
     as the price to be paid for every increase in knowledge, in 
     reasonableness, in co-operation and in mutual help, and 
     consequently in our chances of survival, and in the size of 
     the population. It is the price we have to pay for being 
     human.

          The strain is most closely related to the problem of 
     the tension between the classes which is raised for the 
     first time by the breakdown of the closed society. The 
     closed society itself does not know this problem. At least 
     to its ruling members, slavery, caste, and class rule are 
     ‘natural’ in the sense of being unquestionable. But with 
     the breakdown of the closed society, this certainty