'I don't know' has become 'I don't know yet'.

The genius of capitalism lies in its ability to make self-interest serve the wider interest. The potential of a big financial return for innovation unleashes a broad set of talented people in pursuit of many different discoveries. This system, driven by self-interest, is responsible for the incredible innovations that have improved so many lives.

Even in some of our vaccine areas, like an AIDS vaccine, things have taken longer than we expected, but we have the pipeline of tools. The biological information that we have that gives us insights is fantastic.

Even for the diseases we don't focus on, cancer, heart disease, you're going to be way better off being sick 10 years from now than any time in the past.

But the improvements will happen faster and last longer if we can channel market forces, including innovation that's tailored to the needs of the poorest, to complement what governments and nonprofits do. We need a system that draws in innovators and businesses in a far better way than we do today.

People in business understand paying money to be more efficient. You can bootstrap markets where the devices are too expensive at first because these are so valuable to some people.

The part of uranium that's fissile - when you hit it with a neutron, it splits in two - is about 0.7%. The reactors we have today are burning that 0.7%.