  A figure of 5% a year for \(\mu\) implies a capital-output ratio \((1/\mu)\) of 20 years, which is far higher than the estimates of capital-output ratios from inter-industry studies that economists in various parts of the world have arrived at (Behrman, 2001); a representative figure for 1/\(\mu\) in that literature is 3 years. But their estimates have been based on a definition of “capital” that is confined to “produced” capital, such as factories, roads, ports, and buildings. Human capital (education, health, knowledge) is missing from them, as is natural capital (ecosystems, sub-soil resources). Ramsey’s model, as encapsulated in equation (11a), embraces all forms of capital goods. No doubt his formulation requires a heroic (read, impossible!) feat of aggregation, but when all capital goods that enter production are taken into account, we should expect an aggregate capital-output ratio (which we should call the (inclusive) wealth-output ratio), to be a lot higher than 3 years; perhaps even higher than 20 years (Arrow et al., 2012, 2013). Large categories of capital goods are absent from the national economic accounts that inform we economists’ understanding of production and consumption possibilities (Dasgupta, 2019). It would thus seem there is still a long way to go before we can reach a good approximation of what we should bequeath to our descendants.