There is no doubt that as an economy grows in a great way like India has, that you have to step back and change your tax systems, because you start to get more disparities of wealth.

The world is very disparate, in terms of the US using the most energy per person, and then the other rich countries - Europe, Japan, New Zealand - using about half of what we do, and then the world average being about a fifth of what we use, with China just now surpassing the world average.

Imagine the disincentive to software development if after months of work another company could come along and copy your work and market it under its own name...without legal restraints to such copying, companies like Apple could not afford to advance the state of the art.

As for drugs - well, Gates was certainly not unusual there. Marijuana was the pharmaceutical of choice.

Nobody has a guaranteed position in computer technologies business. We've done some good work, but all of these products become obsolete so fast and the structure of the business as it broadens out is going to be so different.

Hopefully, whether it's energy or child vaccines, the case of the many benefits helping countries so that they are stable, so these refugee problems that have been troubling for Europe - a little less so for the U.S. but, even so, a lot of controversy there - these things are why the future's going to be better than the past. People really do look to the United States, so we'll be there making the case.

Other paths would include making nuclear fission cheap enough and safe enough that people broadly embrace it, so that could be scaled up.