Most of them had brought their own lecterns, and there was a short silent scramble as they got them out and running. While they were at it Fort stood up and began walking in a circle behind their couches, making a revolution every few sentences. Difficult! Art wrote. Continued?

“We now use about eighty percent of the net primary product of land-based photosynthesis,” he said. “One hundred percent is probably impossible to reach, and our long-range carrying capacity has been estimated to be thirty percent, so we are massively overshot, as they say. We have been liquidating our natural capital as if it were disposable income, and are nearing depletion of certain capital stocks, like oil, wood, soil, metals, fresh water, fish, and animals. This makes continued economic expansion difficult.”

“We have to continue,” Fort said, with a piercing glance at Art, who unobtrusively sheltered his lectern with his arm. “Continuous expansion is a fundamental tenet of economics. Therefore one of the fundamentals of the universe itself. Because everything is economics. Physics is cosmic economics, biology is cellular economics, the humanities are social economics, psychology is mental economics, and so on.”

His listeners nodded unhappily.

“So everything is expanding. But it can’t happen in contradiction to the law of conservation of matter-energy. No matter how efficient your throughput is, you can’t get an output larger than the input.”

Art wrote on his note page, Output larger than input— everything economics— natural capital— Massively Overshot.

“In response to this situation, a group here in Praxis has been working on what we call full-world economics.”

“Shouldn’t that be overfull-world?” Art asked.

Fort didn’t appear to hear him. “Now as Daly said, man-made capital and natural capital are not substitutable. This is obvious, but since most economists still say they are substitutable, it has to be insisted on. Put simply, you can’t substitute more sawmills for fewer forests. If you’re building a house you can juggle the number of power saws and carpenters, which means they’re substitutable, but you can’t build it with half the amount of lumber, no matter how many saws or carpenters you have. Try it and you have a house of air. And that’s where we live now.”

Art shook his head and looked down at his lectern page, which he had filled again. Resources and capital nonsubstitutable— power saws/carpenters— house of air.

“Excuse me?” Sam said. “Did you say natural capital?”

Fort jerked, turned around to look at Sam. “Yes?”

“I thought capital was by definition man-made. The produced means of production, we were taught to define it.”

“Yes. But in a capitalist world, the word capital has taken on more and more uses. People talk about human capital, for instance, which is what labor accumulates through education and work experience. Human capital differs from the classic kind in that you can’t inherit it, and it can only be rented, not bought or sold.”