Because of technological limits, there is a certain amount of food that we can produce per acre. If we were to have intensive greenhouse agriculture, we could have much higher production.

We see an entire planet which has many limitations.

We are looking at a future where to a first approximation everyone is wealthy.

If you think the technology is infeasible, you don't worry about what it might do and what its potential is.

Machines built by human beings they will function correctly if we provide them with a very specific environment. But if that environment is changed they won't function at all.

One of the things that we can say with confidence is that we will have much lighter, much stronger materials, and this will reduce the cost of air flight, and it will reduce the cost of rockets.

Because of technological limits, there is a certain amount of food that we can produce per acre. If we were to have intensive greenhouse agriculture, we could have much higher production.