No. 2, we believe that young people have to be a key part of building that ethos One of the reasons for that is purely demographic.

其次，我们认为青年人,必须成为建立该社会风气的主力,其中的一个原因,纯粹是从人口统计学来考虑的。

普林斯顿公开课 - 人性课程节选

Most censuses were taken, by the way, as a way of counting heads, the number of people who had to be fed at the time of a siege.

顺便提一下,大多数人口普查,都采用数人头的方法,即在围城期间统计需要给养多少人口

耶鲁公开课 - 欧洲文明课程节选