argument has been the subject of papers by Robert J. Gordon. It has also been written about by Owen. C. Paepke and Tyler Cowen. Secular stagnation has also been linked to the rise of the digital economy. Carl Benedikt Frey, for example, has suggested that digital technologies are much less capital-absorbing, creating only little new investment demand relative to other revolutionary technologies. Another is that the damage done by the Great Recession was so long-lasting and permanent, so many workers will never get jobs again, that we really can't recover. A third is that there is a "persistent and disturbing reluctance of businesses to invest and consumers to spend", perhaps in part because so much of the recent gains have gone to the people at the top, and they tend to save more of their money than people—ordinary working people who can't afford to do that. A fourth is that advanced economies are just simply paying the price for years of inadequate investment in infrastructure and education, the basic ingredients of growth. A fifth is related to decreased mortality and increased longevity, thus changes in the demographic structure in advanced economies, affecting both demand, through increased savings, and supply, through reduced innovation activities. And a sixth is that economic growth is largely related to the concept of energy returned on energy invested (EROEI), or energy surplus, which with the discovery of fossil fuels shot up to very high and historically unprecedented levels. This allowed, and in effect fueled, dramatic increases in human consumption since the Industrial Revolution and many related technological advances. Under this argument, diminishing and increasingly difficult to access fossil fuel reserves directly lead to significantly reduced EROEI, and therefore put a brake on, and potentially reverse, long-term economic growth, leading to secular stagnation. Linked to the EROEI argument are those stemming from the Limits to Growth school of thinking, whereby environmental and resource constraints in general are likely to impose an eventual limit on the continued expansion of human consumption and incomes. While 'limits to growth' thinking went out of fashion in the decades following the initial publication in 1972, a recent study shows human development continues to align well with the 'overshoot and collapse' projection outlined in the standard run of the original analysis, and this is before factoring in the potential effects of climate change. A 2018 CUSP working paper by Tim Jackson, The Post-Growth