The concept of productivity in America is income divided by labor. So if you're Goldman Sachs and you pay yourself $20 million a year in salary and bonuses, you're considered to have added $20 million to GDP, and that's enormously productive. So we're talking in a tautology. We're talking with circular reasoning here.

The other dynamic keeping the stock market up - both for technology stocks and others - is that companies are using a lot of their income for stock buybacks and to pay out higher dividends, not make new investment,. So to the extent that companies use financial engineering rather than industrial engineering to increase the price of their stock you're going to have a bubble. But it's not considered a bubble, because the government is behind it, and it hasn't burst yet.

Mr. Trump wants to turn the U.S. economy into the kind of real estate development that has made him so rich in New York. It will make his fellow developers rich, and it will make the banks that finance this infrastructure rich, but the people are going to have to pay for it in a much higher cost for transportation, much higher cost for all the infrastructure that he’s proposing. You could call Trump's plan "public investment to create private profit". That's really his plan in a summary.

As you have to pay more interest and amortization on what you owe, you're left with less and less money to buy goods and services - unless you borrow even more and go further into debt.

I don't think that governments should permit speculation in raw materials, because they're what the economy basically needs.

High prices can be the result of speculation, and maybe plunging prices can be attributed to the end of speculation, but low prices over time aren't caused by speculation. That's oversupply, mainly by Saudi Arabia flooding the market with low-priced oil to discourage rival oil producers, whether it's Russian oil or American fracking.

People think that this concept of GDP is scientific economics, partly because it has a precise number and can be quantified. But the underlying concept of "the market" makes it appear as if today's poverty is natural. It makes it appear that Goldman Sachs and Donald Trump are job creators instead of job destroyers. That is illogical, when you think about it.