In this paper, we transform the age-old wisdom that societies change through generational replacement into a formalized model that allows for quantitative forecasts of such societal changes for decades into the future. Using the term “Demographic Metabolism” which was introduced by Norman Ryder 50 years ago, we show how the blend of this concept with the methods of multi-dimensional population dynamics results in a sophisticated model with strong predictive power, particularly for such characteristics that once established tend to be sticky along cohort lines. We evaluate this model empirically and give a comprehensive summary of recent applications to the reconstruction and projection of educational attainment distributions by age and sex for all countries of the world that already resulted in major new assessments of the societal level returns to education. We revisit the past application of the model for forecasting the future spread of the prevalence of European identity in the EU and show that despite of the recent European crisis, the Demographic Metabolism continued to work as projected. Finally, we apply the model to the changing attitudes towards homosexuality in Japan, Spain and the USA and produce projections of the average tolerance levels in those countries up to 2040
