Tom Murphy's website occasionally comes up in futurist circles. His general point that unbounded exponential growth is impossible is obviously correct, but I find his condescending attitude tiresome and he often exaggerates the apparent validity of his pessimism through questionable arguments.

For example, he first insists that the conversation about energy consumption be confined to Earth and ignore space exploration, which is reasonably sensible because of the large energy cost of space travel. He moves from there to a thermodynamic bound on energy dissipation from Earth into space via black-body radiation. This argument is self-contradictory: if we were producing so much energy that it were able to heat the atmosphere (>1000x today), we would certainly have enough energy to fly into space. (The linked article "Why not space?" contains no math and few real arguments: https://dothemath.ucsd.edu/2011/10/why-not-space/ )

Also, this paragraph is relatively good evidence he didn't talk to a real economist:

>But if energy became arbitrarily cheap, someone could buy all of it, and suddenly the activities that comprise the economy would grind to a halt. Food would stop arriving at the plate without energy for purchase, so people would pay attention to this. Someone would be willing to pay more for it. Everyone would. There will be a floor to how low energy prices can go as a fraction of GDP.

None of this hemming and hawing about infinity answers the real question: is it possible for the global economy to grow until nobody has to live in mud-huts without air conditioning? The answer is almost certainly yes.