Re: Current US (and World) Economy (Hot!)
To answer the question ... A big part of it is what is coming in vs. going out of the economic ecosystem, and how fast that money is moving WITHIN that ecosystem.
To illustrate the first, imagine you have an insulated community with 10 people. You start paying your 5 employees 50% more. They now have more money to spend on things like better food, chairs, cars and so on (so they do). That gives more money to the farmers and chair makers, who then have more money to spend on whatever you're selling. The downside is that it creates inflation. While the chair maker can hire more people to keep up with demand, the farmer only has enough acres and cows to grow 9 steaks a month (from the steak tree, you know). So the 10 citizens who want steak are caught in a bidding war, which drives up price, which means that if you're the 1 guy who couldn't afford steaks before, even doubling your salary, you probably still can't afford steaks.
I don't know the details on how increasing the money flow filters into increased wealth vs. increased inflation. A big part of it is capped by production and consumption. If everyone already has 20 chairs, paying everyone more won't help them buy more chairs. Similarly, if you're capped at 9 steaks, paying everyone more won't help the poor get more steak. However, at least according to Keynes, in situations like the Great Depression, this sort of thing does ultimately kick start a strong cycle of work, puts trust back in the system, and gets that spending going.
The second party is the money going in and out of the ecosystem. Imagine our little community likes Japanese stuff, so everyone has a Japanese car, television, chair, rice cooker and so on. If I increase the pay to my employees, they don't spend their money on local chairs and steaks, they send it to Japan to buy THEIR chairs and steaks. And if my community isn't competitive, for instance it costs us $20 to make a chair and it costs $10 to make one in Japan, no one is buying our chairs so no money is coming in. Money drains out of the community and eventually everyone is poor.
That's the big problem with the US. You can't hire manufacturing jobs here - people who work at plants still want a 40 hour work week, health care, a house, a car, a television and steak once every two weeks. That's expensive. A worker in China wants not to be beaten. If our workers are not willing to reduce their salaries to be competitive with the Chinese, all else being equal, our cars will not sell outside of the US, they won't be able to make any profit, and ultimately can't stay in business.
That's also the problem with government programs to make jobs. Sure, you can pay someone $20 to dig a hole, but it's not bringing any money into the community. Most of the solutions as of late have been focused on the first solution (make money move faster) and not on the second (make money move faster - into the US). To a degree this is justified - people don't spend because they're afraid, and so that's depressing the economy. But over the long haul, it's not the big issue.
So, in theory, industry is a business that produces a good or service with the purpose of making profit.
Government is an organization with the ability and responsibility of regulating the country, and usually makes money from taxing industry and individuals, and does not create a profit.
Industry grows based on a number of metrics, including profit, production and number of employees and assets.
Government grows based on its spending and number of employees and assets.
Investing means taking any resources (normally money) and making it unavailable for use, with the intention and hope that it will become available for use again, with a positive interest.