The purest case of an intelligence explosion would be an Artificial Intelligence rewriting its own source code. The key idea is that if you can improve intelligence even a little, the process accelerates. It's a tipping point. Like trying to balance a pen on one end - as soon as it tilts even a little, it quickly falls the rest of the way.

By far, the greatest danger of Artificial Intelligence is that people conclude too early that they understand it.

Anything that could give rise to smarter-than-human intelligence - in the form of Artificial Intelligence, brain-computer interfaces, or neuroscience-based human intelligence enhancement - wins hands down beyond contest as doing the most to change the world. Nothing else is even in the same league.

There's a popular concept of 'intelligence' as book smarts, like calculus or chess, as opposed to, say, social skills. So people say that 'it takes more than intelligence to succeed in human society.' But social skills reside in the brain, not the kidneys.

Right now, oil is being isolated around the globe, and there is a major effort in shipping, trucking and otherwise transporting that oil around to a very finite number of refineries. Biology allows us to make these same fuels in a much more distributed fashion.

Biology is a software process. Our bodies are made up of trillions of cells, each governed by this process. You and I are walking around with outdated software running in our bodies, which evolved in a very different era.

Moonshots live in that place between audacious projects and pure science fiction.

I did the first proofreading of 'A Brief History of Time,' and when it came to writing my memoir, I consulted many scientific friends so that, contrary to what many critics supposed and were churlish enough to voice, I did actually write the scientific sections myself.