小时候听父亲讲故事，讲到古代曾经有法律，人到60岁就要处死。后来因为一些事情，人们认识到老人有其作用，这项法律才被废除。前几天看《Purity and Danger》，其中有一段：

‘The natural religion of the Creeks, Cherokees, Chickasaws and all other Indians, is to torture all their prisoners from morning to night, till
at length they roast them to death. . . . Yea, it is a common thing among them for the son, if he thinks his father lives too long, to knock out his
brains.’
看来在人类社会的早期，可能真有弑父这种传统。

关于《Purity and Danger》这本书的介绍，可参考维基百科：https://en.wikipedia.org/wiki/Purity_and_Danger

在爱问共享资料中可以下载： http://ishare.iask.sina.com.cn/f/36607800.html