要約問題/1983年

次の文章を読み、その要旨を８０字から１００字の日本文で書け。ただし、句読点も字数に数える。

　It is a matter of argument whether we should wonder at the speed with which human kind has mastered a hostile environment, and so created the industrialized world we now inhabit, or, alternatively, despair at the almost agonizing slowness with which primitive man raised himself from such a low position to one of comparative plenty. The "take-off" to self-sustaining industrial growth was achieved towards the end of the eighteenth century. Yet the initial take-off to settled societies, when man (homo sapiens) first began to exploit his biological resources as a rational creature, took place as long ago as the New Stone Age. It was then that the key discoveries were made, or rather came into widespread use: how to grow crops; how to herd, breed and exploit animals; how to use tools; how to pass from mere defence against nature to attack; and in particular how to organize the collective power of the group. These gigantic intellectual leaps, which involved the concept of planning and the development of a sense of time, were more difficult than anything we have performed since. Hence our wonder. But we are also bound to ask why it was that Stone-Age man, having broken through the prison of his environment at a number of related points, took such a long time to make full use of his victories. Should not the process of the ever-increasing speed of development have begun thousands of years ago, instead of a mere hundred?