"I have a strong suspicion that the Keynesian miracle is simply an unimaginably huge bubble founded -- like many financial bubbles -- on a novel "creative" acco

"I have a strong suspicion that the Keynesian miracle is simply an unimaginably huge bubble founded -- like many financial bubbles -- on a novel "creative" accounting technique that temporarily hides underlying physical realities." It's possible. It's also possible that Keynesianism makes a substantial bet on the possibilities of human technological progress which can be stated as the following: If our economy moves forward at a quick enough pace we can engineer our way out of the most serious problems that arise along the way (due to physical constraints such as resource limitations, environmental degradation, etc). Whether or not this is true remains to be seen. An example of this might be your example of carbon emissions. The economy might solve it thusly: As soon as clean energy sources such as solar and wind reach such a price that it does not make fiscal sense not to have them, they will proliferate as fast as we can build them. Worldwide carbon emissions will take a nose dive and the problem of global warming may reverse or at the very least stall. We might get ourselves to this price point faster by employing Keynesian policies of government spending as China has - i.e., providing government funded subsidies to push the price artificially down. If this happens, then we will have bought ourselves time to deal with the next set of potentially lethal problems that arise due to our economic growth. (Your links touch on this but I do not agree that our economy will keep going full steam ahead until collapsing due to insufficient energy supplies. That would meant that our economy has no reflexivity and no built-in foresight, which it does.)