If you look at the percent of time people in society were involved in various activities and broken into agriculture versus everything else, in ancient Egypt it looked like this.

如果你留意一下,人们从事各种社会活动的时间比例,被分为农业生产和其他活动两类,在古埃及,时间分配是这样的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

There are more people who can work to increase the production, but beyond that point there are more people to feed than the production can produce, and that leads to a desire for expansion of the land available for cultivation.

越来越多的人从事工作,生产力得以提高,但是一旦突破临界值,花费就要超过所得了,它导致了对土地扩张的需求

耶鲁公开课 - 古希腊历史简介课程节选