The classic 1965 article by the Canadian-American demographer Norman Burston Ryder on the cohort concept has inspired generations of social scientists to examine the nature and extent of social change in a wide range of contexts. However, while there have been numerous attempts to develop new methods for analyzing temporally structured data, there have been strikingly few attempts to elaborate on Ryder’s core theoretical insights. Drawing on his 1965 article as well as a collection of unpublished documents, this article fills this gap by developing a new, general Ryderian theory of social change. I first discuss the main features of the overall theoretical framework, focusing on the sociocultural system, the cohort concept, and the problem of persistence. Next, I outline a “processual” account of social change, introducing the key distinction between structure, process, and transformation as well as revealing how a Ryderian approach, using insights from demography, can be generalized to encompass a diverse array of structural changes. I conclude with a discussion on promising directions for additional research based on Ryder’s ideas.

加拿大裔美国人口统计学家 Norman Burston Ryder 在 1965 年发表的关于群体概念的经典文章激励了几代社会科学家在广泛的背景下研究社会变革的性质和程度。然而，尽管人们多次尝试开发分析时间结构化数据的新方法，但详细阐述莱德核心理论见解的尝试却少之又少。本文借鉴他 1965 年的文章以及一系列未发表的文件，通过发展一种新的、通用的赖德式社会变革理论来填补这一空白。我首先讨论整体理论框架的主要特征，重点讨论社会文化系统、群体概念和持久性问题。接下来，我概述了社会变革的“过程”说明，介绍结构、过程和转型之间的关键区别，并揭示如何利用人口统计学的见解将赖德方法推广到涵盖各种结构变化。最后，我讨论了基于莱德的想法的进一步研究的有希望的方向。